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Chris King
Jan 8, 2012, 6:24:35 PM1/8/12
to
Just started to get back into model railroading and OO gauge.
As a newbie, needed to run a few simple questions past other model
railway users.
Running Hornby DCC select as my first step into DCC - plan to upgrade
to a better DCC later finances allowing).
Sorry if I listed the issues like bullet points, but felt it would make
each issue easy to reply to.
a) My track layout is now built and using a dual circuit, I have all
the points electro connected for DCC.
Should I supply DCC connection to both tracks using a link wire, even
though the points and track are all live?
b) Running two locomotives (but with two others not selected) in
sidings, runs fine on the DCC controller, but every so often, the
engines both stop and the controller reboots (then both engines resume
running). There are no shorts I can see, and at first I thought it was
points related with the electro connected, but have elimated that. The
power supply is 1amp as its the basic power unit that came with the
Hornby Select. Do I need the larger 4amp supply? or is the 1amp
sufficient? (Also thought a loco was shorting it at one point, but
eliminated that as a cause as well).
Finally:
c) I have the point motors, enough for each point on my track (6 in
total) and two point controllers each allowing 4 points/accessories.
However wherever I put the DCC point controllers, I am going to be
lucky if the wires from the point motors reached the controller for all
6, dont really want to buy a seperate DCC point controller for each, so
I suppose I need to extend the wires from the points. Is there no quick
easy way to do this without soldering or extending the wires? seems
silly that the wires are so short!
Thanks all!
Also posted in rec.models.railroad
--
Chris King
(remove nospam to email direct)
As a newbie, needed to run a few simple questions past other model
railway users.
Running Hornby DCC select as my first step into DCC - plan to upgrade
to a better DCC later finances allowing).
Sorry if I listed the issues like bullet points, but felt it would make
each issue easy to reply to.
a) My track layout is now built and using a dual circuit, I have all
the points electro connected for DCC.
Should I supply DCC connection to both tracks using a link wire, even
though the points and track are all live?
b) Running two locomotives (but with two others not selected) in
sidings, runs fine on the DCC controller, but every so often, the
engines both stop and the controller reboots (then both engines resume
running). There are no shorts I can see, and at first I thought it was
points related with the electro connected, but have elimated that. The
power supply is 1amp as its the basic power unit that came with the
Hornby Select. Do I need the larger 4amp supply? or is the 1amp
sufficient? (Also thought a loco was shorting it at one point, but
eliminated that as a cause as well).
Finally:
c) I have the point motors, enough for each point on my track (6 in
total) and two point controllers each allowing 4 points/accessories.
However wherever I put the DCC point controllers, I am going to be
lucky if the wires from the point motors reached the controller for all
6, dont really want to buy a seperate DCC point controller for each, so
I suppose I need to extend the wires from the points. Is there no quick
easy way to do this without soldering or extending the wires? seems
silly that the wires are so short!
Thanks all!
Also posted in rec.models.railroad
--
Chris King
(remove nospam to email direct)
Bill Campbell
Jan 9, 2012, 3:55:18 AM1/9/12
to
Hi Chris
It is generally accepted that the DCC power bus should be connected to
every part of the running rails.
It looks as though you are trying to draw more power than the 1 amp
supply - you need to allow about half an amp per loco when moving plus a
small amount for those sitting stationary plus the load from accessories
such as point motors. You need a heavier power supply.
Hornby do not appear to list extension leads for their point controllers
- they don't even have the accessory controller on their own website!
You can easily extend the leads using similar wire by using screw
connector blocks to join the wire.
Regards.
In message <201201082324359803-chris@nospamckingfreeonlinecouk>, Chris
King <ch...@nospam.cking.free-online.co.uk> writes
Bill Campbell
It is generally accepted that the DCC power bus should be connected to
every part of the running rails.
It looks as though you are trying to draw more power than the 1 amp
supply - you need to allow about half an amp per loco when moving plus a
small amount for those sitting stationary plus the load from accessories
such as point motors. You need a heavier power supply.
Hornby do not appear to list extension leads for their point controllers
- they don't even have the accessory controller on their own website!
You can easily extend the leads using similar wire by using screw
connector blocks to join the wire.
Regards.
In message <201201082324359803-chris@nospamckingfreeonlinecouk>, Chris
King <ch...@nospam.cking.free-online.co.uk> writes
>
>a) My track layout is now built and using a dual circuit, I have all
>the points electro connected for DCC.
>Should I supply DCC connection to both tracks using a link wire, even
>though the points and track are all live?
>b) Running two locomotives (but with two others not selected) in
>sidings, runs fine on the DCC controller, but every so often, the
>engines both stop and the controller reboots (then both engines resume
>running). There are no shorts I can see, and at first I thought it was
>points related with the electro connected, but have elimated that. The
>power supply is 1amp as its the basic power unit that came with the
>Hornby Select. Do I need the larger 4amp supply? or is the 1amp
>sufficient? (Also thought a loco was shorting it at one point, but
>eliminated that as a cause as well).
>Finally:
>c) I have the point motors, enough for each point on my track (6 in
>total) and two point controllers each allowing 4 points/accessories.
>However wherever I put the DCC point controllers, I am going to be
>lucky if the wires from the point motors reached the controller for all
>6, dont really want to buy a seperate DCC point controller for each, so
>I suppose I need to extend the wires from the points. Is there no quick
>easy way to do this without soldering or extending the wires? seems
>silly that the wires are so short!
--
>a) My track layout is now built and using a dual circuit, I have all
>the points electro connected for DCC.
>Should I supply DCC connection to both tracks using a link wire, even
>though the points and track are all live?
>b) Running two locomotives (but with two others not selected) in
>sidings, runs fine on the DCC controller, but every so often, the
>engines both stop and the controller reboots (then both engines resume
>running). There are no shorts I can see, and at first I thought it was
>points related with the electro connected, but have elimated that. The
>power supply is 1amp as its the basic power unit that came with the
>Hornby Select. Do I need the larger 4amp supply? or is the 1amp
>sufficient? (Also thought a loco was shorting it at one point, but
>eliminated that as a cause as well).
>Finally:
>c) I have the point motors, enough for each point on my track (6 in
>total) and two point controllers each allowing 4 points/accessories.
>However wherever I put the DCC point controllers, I am going to be
>lucky if the wires from the point motors reached the controller for all
>6, dont really want to buy a seperate DCC point controller for each, so
>I suppose I need to extend the wires from the points. Is there no quick
>easy way to do this without soldering or extending the wires? seems
>silly that the wires are so short!
Bill Campbell
manat...@hotmail.com
Jan 9, 2012, 9:32:38 AM1/9/12
to
On Jan 8, 11:24 pm, Chris King <ch...@nospam.cking.free-online.co.uk>
wrote:
> a) My track layout is now built and using a dual circuit, I have all
> the points electro connected for DCC.
Depends what you mean by "electro connected". That's not a recognised
term. See http://www.wiringfordcc.com/ for more than you ever wante to
know. I would also join MRF http://www.modelrailforum.com/forums/index.php?
which has a much more active DCC forum than the traffic here.
> Should I supply DCC connection to both tracks using a link wire, even
> though the points and track are all live?
You should run the two wires from the controll as a "bus" aroound the
layout and connect the the track at regular interval (known as
"dropper wires"), preferably every piece of track, to avoid relying on
electrical continuity of rail joiners (aka fishplates). Whan you move
up to a bigger system you caould have 5 or even 10 amps flowing ina
short circuit and it's important that all wiring is low impedance. It
should also be mitigated by using "power districts" but that's a
subject fro another post.
> b) Running two locomotives (but with two others not selected) in
> sidings, runs fine on the DCC controller, but every so often, the
Assuming OO or smaller, and modern locos, then 1 Amp is more than
adequate for this.
> engines both stop and the controller reboots (then both engines resume
> running). There are no shorts I can see, and at first I thought it was
If the engines resume as they were then I would question the use of
"reboot". If it has "rebooted" then I would expect everything to be in
a quescent state. otherwise locos couls start running every time you
turn the thing on.
> points related with the electro connected, but have elimated that. The
> power supply is 1amp as its the basic power unit that came with the
> Hornby Select. Do I need the larger 4amp supply? or is the 1amp
> sufficient? (Also thought a loco was shorting it at one point, but
> eliminated that as a cause as well).
It sounds like a momentary short. Again, review the wiring for DCC
site and ensure you are not getting shorts on your points.
> Finally:
> c) I have the point motors, enough for each point on my track (6 in
> total) and two point controllers each allowing 4 points/accessories.
> However wherever I put the DCC point controllers, I am going to be
> lucky if the wires from the point motors reached the controller for all
> 6, dont really want to buy a seperate DCC point controller for each, so
> I suppose I need to extend the wires from the points. Is there no quick
> easy way to do this without soldering or extending the wires? seems
> silly that the wires are so short!
Twin-coil solenoid point motors? These take a very large current. The
wiring needs to be as thick and short as possible for best results. Do
the Hornby accessory decoders have a built in CDU? If not, I would not
power them from the track bus.
MBQ
wrote:
> Just started to get back into model railroading and OO gauge.
> As a newbie, needed to run a few simple questions past other model
> railway users.
> Running Hornby DCC select as my first step into DCC - plan to upgrade
> to a better DCC later finances allowing).
A good policy!
> As a newbie, needed to run a few simple questions past other model
> railway users.
> Running Hornby DCC select as my first step into DCC - plan to upgrade
> to a better DCC later finances allowing).
> a) My track layout is now built and using a dual circuit, I have all
> the points electro connected for DCC.
term. See http://www.wiringfordcc.com/ for more than you ever wante to
know. I would also join MRF http://www.modelrailforum.com/forums/index.php?
which has a much more active DCC forum than the traffic here.
> Should I supply DCC connection to both tracks using a link wire, even
> though the points and track are all live?
layout and connect the the track at regular interval (known as
"dropper wires"), preferably every piece of track, to avoid relying on
electrical continuity of rail joiners (aka fishplates). Whan you move
up to a bigger system you caould have 5 or even 10 amps flowing ina
short circuit and it's important that all wiring is low impedance. It
should also be mitigated by using "power districts" but that's a
subject fro another post.
> b) Running two locomotives (but with two others not selected) in
> sidings, runs fine on the DCC controller, but every so often, the
adequate for this.
> engines both stop and the controller reboots (then both engines resume
> running). There are no shorts I can see, and at first I thought it was
"reboot". If it has "rebooted" then I would expect everything to be in
a quescent state. otherwise locos couls start running every time you
turn the thing on.
> points related with the electro connected, but have elimated that. The
> power supply is 1amp as its the basic power unit that came with the
> Hornby Select. Do I need the larger 4amp supply? or is the 1amp
> sufficient? (Also thought a loco was shorting it at one point, but
> eliminated that as a cause as well).
site and ensure you are not getting shorts on your points.
> Finally:
> c) I have the point motors, enough for each point on my track (6 in
> total) and two point controllers each allowing 4 points/accessories.
> However wherever I put the DCC point controllers, I am going to be
> lucky if the wires from the point motors reached the controller for all
> 6, dont really want to buy a seperate DCC point controller for each, so
> I suppose I need to extend the wires from the points. Is there no quick
> easy way to do this without soldering or extending the wires? seems
> silly that the wires are so short!
wiring needs to be as thick and short as possible for best results. Do
the Hornby accessory decoders have a built in CDU? If not, I would not
power them from the track bus.
MBQ
Chris King
Jan 9, 2012, 2:25:30 PM1/9/12
to
Hi Bill
Think after consulation with a model railway shop and an assistant who
has his own DCC layout, I have not used insulating fish plates on the
inner rail. These are now on order and en-route.
Think after consulation with a model railway shop and an assistant who
has his own DCC layout, I have not used insulating fish plates on the
inner rail. These are now on order and en-route.
Chris King
Jan 9, 2012, 2:37:19 PM1/9/12
to
On 2012-01-09 14:32:38 +0000, manat...@hotmail.com said:
> On Jan 8, 11:24 pm, Chris King <ch...@nospam.cking.free-online.co.uk>
> wrote:
>>
>> Running Hornby DCC select as my first step into DCC - plan to upgrade
>> to a better DCC later finances allowing).
>
> A good policy!
>
>> a) My track layout is now built and using a dual circuit, I have all
>> the points electro connected for DCC.
>
> Depends what you mean by "electro connected". That's not a recognised
> term. See http://www.wiringfordcc.com/ for more than you ever wante to
> know. I would also join MRF http://www.modelrailforum.com/forums/index.php?
> which has a much more active DCC forum than the traffic here.
point clips. what I omitted was the insulating plates on the inner
rails on each point. This is being rectified.
>
>> Should I supply DCC connection to both tracks using a link wire, even
>> though the points and track are all live?
>
> You should run the two wires from the controll as a "bus" aroound the
> layout and connect the the track at regular interval (known as
> "dropper wires"), preferably every piece of track, to avoid relying on
> electrical continuity of rail joiners (aka fishplates). Whan you move
> up to a bigger system you caould have 5 or even 10 amps flowing ina
> short circuit and it's important that all wiring is low impedance. It
> should also be mitigated by using "power districts" but that's a
> subject fro another post.
inner track too, small house and no plans to move!
>
>> b) Running two locomotives (but with two others not selected) in
>> sidings, runs fine on the DCC controller, but every so often, the
>
> Assuming OO or smaller, and modern locos, then 1 Amp is more than
> adequate for this.
inner rail on points.
>
>> engines both stop and the controller reboots (then both engines resume
>> running). There are no shorts I can see, and at first I thought it was
>
> If the engines resume as they were then I would question the use of
> "reboot". If it has "rebooted" then I would expect everything to be in
> a quescent state. otherwise locos couls start running every time you
> turn the thing on.
watch the display, but again, seems I missed the insulating plates!.
>
>> points related with the electro connected, but have elimated that. The
>> power supply is 1amp as its the basic power unit that came with the
>> Hornby Select. Do I need the larger 4amp supply? or is the 1amp
>> sufficient? (Also thought a loco was shorting it at one point, but
>> eliminated that as a cause as well).
>
> It sounds like a momentary short. Again, review the wiring for DCC
> site and ensure you are not getting shorts on your points.
>
>> Finally:
>> c) I have the point motors, enough for each point on my track (6 in
>> total) and two point controllers each allowing 4 points/accessories.
>> However wherever I put the DCC point controllers, I am going to be
>> lucky if the wires from the point motors reached the controller for all
>> 6, dont really want to buy a seperate DCC point controller for each, so
>> I suppose I need to extend the wires from the points. Is there no quick
>> easy way to do this without soldering or extending the wires? seems
>> silly that the wires are so short!
>
> Twin-coil solenoid point motors? These take a very large current. The
> wiring needs to be as thick and short as possible for best results. Do
> the Hornby accessory decoders have a built in CDU? If not, I would not
> power them from the track bus.
driving 4 points from each one, I can power them from the track bus, my
moan was the wires supplied on each point motor is pitiful, so need to
extend them :( Why cant they supply them each with say 1-2 metres wire.
I suppose its cost!
Jerry
Jan 9, 2012, 3:54:41 PM1/9/12
to
<manat...@hotmail.com> wrote in message
news:a3e8ebcc-5e95-4e56...@t30g2000vbx.googlegroups.com...
<snipped for brevity>
: Twin-coil solenoid point motors? These take a very
: large current. The wiring needs to be as thick and
: short as possible for best results.
You really don't understand the relation between voltage drop,
: short as possible for best results.
distance and conductor size do you MBQ?! What you wrote above
makes no sense what so ever, are you /really/ saying that you
would use say 4.0mm wire if the distance between the power source
and load was 300mm apart, because that is what you have implied.
OTOH you may well need to use a 10烯m solid busbar if your load
is 1000+ ft away!... :~)
: Do the Hornby accessory decoders have a built in CDU?
For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
Not sure if a CDU would actually make any difference, just alter
when any problem might exist, whilst a CDU no doubt allows less
power to be drawn /during/ the solenoid operation the same -if
not greater- power is still consumed due to the CDU needing to
recharge *after operation/discharge*.
--
Regards, Jerry.
simon
Jan 9, 2012, 4:32:46 PM1/9/12
to
"Jerry" <mapson...@btinternet.INVALID> wrote in message
news:jefkvd$ibr$1...@dont-email.me...
If you still have the Select then its useful to use it solely for the
points - avoids any power drain on main controller whilst points recharging.
Have you decided if you want computer control, Hornby Trackmaster looks
rather good, but only works for the Elite.
Length of wire - well thats typical of most devices nowadays, probably
manufacturers say most people happy with that length and would be a waste to
supply more - wouldnt comment on if they are correct cos dont know.
Cheers,
Simon
manat...@hotmail.com
Jan 9, 2012, 4:50:24 PM1/9/12
to
On Jan 9, 9:32 pm, "simon" <nos...@nospam.com> wrote:
> "Jerry" <mapson.sca...@btinternet.INVALID> wrote in message
>
> news:jefkvd$ibr$1...@dont-email.me...
>
>
>
>
>
>
>
>
>
> > <manatba...@hotmail.com> wrote in message
shuts down after a short due to running against the points.
> Have you decided if you want computer control, Hornby Trackmaster looks
> rather good, but only works for the Elite.
If running trains into the buffers in lieu of proper control of
stopping is good... At least that's what I heard about the early
versions. If you want to pay for software then go for RR&Co, otherwise
look at JMRI or Rocrail.
MBQ
> "Jerry" <mapson.sca...@btinternet.INVALID> wrote in message
>
> news:jefkvd$ibr$1...@dont-email.me...
>
>
>
>
>
>
>
>
>
> > <manatba...@hotmail.com> wrote in message
> >news:a3e8ebcc-5e95-4e56...@t30g2000vbx.googlegroups.com...
>
> > <snipped for brevity>
> > : Twin-coil solenoid point motors? These take a very
> > : large current. The wiring needs to be as thick and
> > : short as possible for best results.
>
> > You really don't understand the relation between voltage drop,
> > distance and conductor size do you MBQ?! What you wrote above
> > makes no sense what so ever, are you /really/ saying that you
> > would use say 4.0mm wire if the distance between the power source
> > and load was 300mm apart, because that is what you have implied.
> > OTOH you may well need to use a 10 mm solid busbar if your load
>
> > <snipped for brevity>
> > : Twin-coil solenoid point motors? These take a very
> > : large current. The wiring needs to be as thick and
> > : short as possible for best results.
>
> > You really don't understand the relation between voltage drop,
> > distance and conductor size do you MBQ?! What you wrote above
> > makes no sense what so ever, are you /really/ saying that you
> > would use say 4.0mm wire if the distance between the power source
> > and load was 300mm apart, because that is what you have implied.
> > is 1000+ ft away!... :~)
>
> > : Do the Hornby accessory decoders have a built in CDU?
>
> > For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>
> > Not sure if a CDU would actually make any difference, just alter
> > when any problem might exist, whilst a CDU no doubt allows less
> > power to be drawn /during/ the solenoid operation the same -if
> > not greater- power is still consumed due to the CDU needing to
> > recharge *after operation/discharge*.
> > --
> > Regards, Jerry.
>
> Yep, point controllers do have inbuilt CDU.
> If you still have the Select then its useful to use it solely for the
> points - avoids any power drain on main controller whilst points recharging.
Good point. Also means points can still be operated if the main system
>
> > : Do the Hornby accessory decoders have a built in CDU?
>
> > For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>
> > Not sure if a CDU would actually make any difference, just alter
> > when any problem might exist, whilst a CDU no doubt allows less
> > power to be drawn /during/ the solenoid operation the same -if
> > not greater- power is still consumed due to the CDU needing to
> > recharge *after operation/discharge*.
> > --
> > Regards, Jerry.
>
> Yep, point controllers do have inbuilt CDU.
> If you still have the Select then its useful to use it solely for the
> points - avoids any power drain on main controller whilst points recharging.
shuts down after a short due to running against the points.
> Have you decided if you want computer control, Hornby Trackmaster looks
> rather good, but only works for the Elite.
stopping is good... At least that's what I heard about the early
versions. If you want to pay for software then go for RR&Co, otherwise
look at JMRI or Rocrail.
MBQ
manat...@hotmail.com
Jan 9, 2012, 4:47:07 PM1/9/12
to
On Jan 9, 8:54 pm, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
> What you wrote above
> makes no sense what so ever, are you /really/ saying that you
> would use say 4.0mm wire if the distance between the power source
> and load was 300mm apart, because that is what you have implied.
> OTOH you may well need to use a 10 mm solid busbar if your load
solenoid point motor can take quite a few amps. Some people claim to
get away with using cat5 wiring to connect them. I would use something
rather thicker.
In simple terms, thicker is better than thinner, shorter is better
than longer.
If the OP doesn't understand my point then hopefully he will come back
for clarification.
>
> : Do the Hornby accessory decoders have a built in CDU?
>
> For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>
> Not sure if a CDU would actually make any difference, just alter
> when any problem might exist, whilst a CDU no doubt allows less
> power to be drawn /during/ the solenoid operation the same -if
> not greater- power is still consumed due to the CDU needing to
> recharge *after operation/discharge*.
You need to understand the difference between power and energy. A CDU
can deliver the neccessary high current pulse, over a short period of
time, to fire a solenoid motor. It delivers a certain amount of energy
into the load.
A CDU is generally designed to recharge over a much longer period,
drawing a much lower current. The energy is the same (plus any losses
in the circuit). The much lower recharge current means that said CDU
*might* be suitable to be powered from the DCC track bus without
upsetting the system too much. With a 1 Amp power supply in the OPs I
would say it's still marginal.
A further possibilty with a CDU is to build a voltage doubler into the
recharge circuit. The energy stored in a capacitor, and available to
deliver to the solenoid, is proportional to the voltage. Personally, I
would look at increasing the capacitance first since energy stored is
proportional to the square of the capacitance.
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:a3e8ebcc-5e95-4e56...@t30g2000vbx.googlegroups.com...
>
> <snipped for brevity>
> : Twin-coil solenoid point motors? These take a very
> : large current. The wiring needs to be as thick and
> : short as possible for best results.
>
> You really don't understand the relation between voltage drop,
> distance and conductor size do you MBQ?!
Yes I do, thank you, nice of you to ask.
> news:a3e8ebcc-5e95-4e56...@t30g2000vbx.googlegroups.com...
>
> <snipped for brevity>
> : Twin-coil solenoid point motors? These take a very
> : large current. The wiring needs to be as thick and
> : short as possible for best results.
>
> You really don't understand the relation between voltage drop,
> distance and conductor size do you MBQ?!
> What you wrote above
> makes no sense what so ever, are you /really/ saying that you
> would use say 4.0mm wire if the distance between the power source
> and load was 300mm apart, because that is what you have implied.
> is 1000+ ft away!... :~)
I would use wire appropriate to the situation. The point is that a
solenoid point motor can take quite a few amps. Some people claim to
get away with using cat5 wiring to connect them. I would use something
rather thicker.
In simple terms, thicker is better than thinner, shorter is better
than longer.
If the OP doesn't understand my point then hopefully he will come back
for clarification.
>
> : Do the Hornby accessory decoders have a built in CDU?
>
> For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>
> Not sure if a CDU would actually make any difference, just alter
> when any problem might exist, whilst a CDU no doubt allows less
> power to be drawn /during/ the solenoid operation the same -if
> not greater- power is still consumed due to the CDU needing to
> recharge *after operation/discharge*.
can deliver the neccessary high current pulse, over a short period of
time, to fire a solenoid motor. It delivers a certain amount of energy
into the load.
A CDU is generally designed to recharge over a much longer period,
drawing a much lower current. The energy is the same (plus any losses
in the circuit). The much lower recharge current means that said CDU
*might* be suitable to be powered from the DCC track bus without
upsetting the system too much. With a 1 Amp power supply in the OPs I
would say it's still marginal.
A further possibilty with a CDU is to build a voltage doubler into the
recharge circuit. The energy stored in a capacitor, and available to
deliver to the solenoid, is proportional to the voltage. Personally, I
would look at increasing the capacitance first since energy stored is
proportional to the square of the capacitance.
MBQ
simon
Jan 9, 2012, 5:31:31 PM1/9/12
to
<manat...@hotmail.com> wrote in message
news:c06bb71d-648a-45d7...@cs7g2000vbb.googlegroups.com...
Don't need computer control to run train into buffers :-)
Will take with pinch of salt, am still amazed at what some people do. When
get own copy then can say what can happen - can even trace commands if
required.
Cheers,
Simon
Riddles
Jan 9, 2012, 6:24:46 PM1/9/12
to
"simon" <nos...@nospam.com> wrote in message
news:lMidncSqcuSfwJbS...@bt.com...
>
Snipped
> Have you decided if you want computer control, Hornby Trackmaster looks
> rather good, but only works for the Elite.
Both products exist but the latter is for layout design using Hornby
sectional track. The computer control system for use with the Elite, is
RAILmaster
Regards,
Riddles
Just zis Guy, you know?
Jan 9, 2012, 6:26:34 PM1/9/12
to
impedance and volt drop. On my old layout I used 4.0mm^2 for the power
bus, the new layout is much bigger but split with a power booster so
the furthest from the controller of any part of the track is about
20ft, this is OK in 2.5 but I run four radials, two in each direction,
and split off to 1.5 then 1.0 before soldering to drops which are 0.5
or less, soldered to the joiners, but kept very short.
I have no power drop issues anywhere, even when running the track
cleaner pushed by the deltic, which is one motor running flat out with
another on the same length of track right behind it.
I'm using a Lenz LZV100 and LV100 booster, four handsets, something
like 500ft of track and up to six engines moving concurrently. Points
are on a separate circuit though.
Guy
--
Guy Chapman, http://www.chapmancentral.co.uk
The usenet price promise: all opinions are guaranteed
to be worth at least what you paid for them.
simon
Jan 9, 2012, 6:50:46 PM1/9/12
to
"Riddles" <railhome...@privacy.net> wrote in message
news:jeft0f$a7i$1...@dont-email.me...
Cheers,
Simon
Jerry
Jan 9, 2012, 7:13:26 PM1/9/12
to
<manat...@hotmail.com> wrote in message
news:ccb55263-f0f6-496f...@a40g2000vbu.googlegroups.com...
<snipped>
: Some people claim to get away with using cat5 wiring
: to connect them. I would use something rather thicker.
:
: In simple terms, thicker is better than thinner, shorter
: is better than longer.
Indeed, in VERY simple terms, but as soon as one grasps relation
:
: In simple terms, thicker is better than thinner, shorter
: is better than longer.
between voltage (drop), current draw, distance and conductor size
plus -in the case of latching solenoids- switching time...
<snip>
: You need to understand the difference between power and energy.
I do thanks, unlike you, your description of a CDU,which is
laughable.
<garbage snipped>
: A further possibilty with a CDU is to build a voltage doubler
: into the recharge circuit. The energy stored in a capacitor,
: and available to deliver to the solenoid, is proportional to
: the voltage
Next you'll be suggesting perpetual motion...
: and available to deliver to the solenoid, is proportional to
: the voltage
--
Regards, Jerry.
David Littlewood
Jan 9, 2012, 10:18:10 PM1/9/12
to
In article
<ccb55263-f0f6-496f...@a40g2000vbu.googlegroups.com>,
"manat...@hotmail.com" <manat...@hotmail.com> writes
only proportional to C.
David
--
David Littlewood
<ccb55263-f0f6-496f...@a40g2000vbu.googlegroups.com>,
"manat...@hotmail.com" <manat...@hotmail.com> writes
>
>A further possibilty with a CDU is to build a voltage doubler into the
>recharge circuit. The energy stored in a capacitor, and available to
>deliver to the solenoid, is proportional to the voltage. Personally, I
>would look at increasing the capacitance first since energy stored is
>proportional to the square of the capacitance.
>
No it isn't; E = 0.5CV^2. That is, proportional to voltage squared but
>A further possibilty with a CDU is to build a voltage doubler into the
>recharge circuit. The energy stored in a capacitor, and available to
>deliver to the solenoid, is proportional to the voltage. Personally, I
>would look at increasing the capacitance first since energy stored is
>proportional to the square of the capacitance.
>
only proportional to C.
David
--
David Littlewood
manat...@hotmail.com
Jan 10, 2012, 3:24:00 AM1/10/12
to
On Jan 10, 12:13 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
Here's a good walk-through http://home.cogeco.ca/~rpaisley4/CDPSU.html
where you will see that any sensible CDU design includes the current
limit on the recharge side. This limits the *power* but allows the
capacitor to charge to almost the full voltage (hence the same
*energy* stored).
> <garbage snipped>
> : A further possibilty with a CDU is to build a voltage doubler
> : into the recharge circuit. The energy stored in a capacitor,
> : and available to deliver to the solenoid, is proportional to
> : the voltage
>
> Next you'll be suggesting perpetual motion...
Why would I need to do that?
Let me know which bit you are struggling with and I'll explain it in
simple terms.
There are plenty of resources on the 'net that will explain the
formula for energy stored in a capacitor.
If you know someone who is a member of MERG then get them to show you
the schematic for the CAN_ACC4, a voltage doubling CDU.
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:ccb55263-f0f6-496f...@a40g2000vbu.googlegroups.com...
>
> <snipped>
> : Some people claim to get away with using cat5 wiring
> : to connect them. I would use something rather thicker.
> :
> : In simple terms, thicker is better than thinner, shorter
> : is better than longer.
>
> Indeed, in VERY simple terms, but as soon as one grasps relation
> between voltage (drop), current draw, distance and conductor size
> plus -in the case of latching solenoids- switching time...
>
> <snip>
> : You need to understand the difference between power and energy.
>
> I do thanks, unlike you, your description of a CDU,which is
> laughable.
Lets hear yours, if you think you can do better.
> news:ccb55263-f0f6-496f...@a40g2000vbu.googlegroups.com...
>
> <snipped>
> : Some people claim to get away with using cat5 wiring
> : to connect them. I would use something rather thicker.
> :
> : In simple terms, thicker is better than thinner, shorter
> : is better than longer.
>
> Indeed, in VERY simple terms, but as soon as one grasps relation
> between voltage (drop), current draw, distance and conductor size
> plus -in the case of latching solenoids- switching time...
>
> <snip>
> : You need to understand the difference between power and energy.
>
> I do thanks, unlike you, your description of a CDU,which is
> laughable.
Here's a good walk-through http://home.cogeco.ca/~rpaisley4/CDPSU.html
where you will see that any sensible CDU design includes the current
limit on the recharge side. This limits the *power* but allows the
capacitor to charge to almost the full voltage (hence the same
*energy* stored).
> <garbage snipped>
> : A further possibilty with a CDU is to build a voltage doubler
> : into the recharge circuit. The energy stored in a capacitor,
> : and available to deliver to the solenoid, is proportional to
> : the voltage
>
> Next you'll be suggesting perpetual motion...
Let me know which bit you are struggling with and I'll explain it in
simple terms.
There are plenty of resources on the 'net that will explain the
formula for energy stored in a capacitor.
If you know someone who is a member of MERG then get them to show you
the schematic for the CAN_ACC4, a voltage doubling CDU.
MBQ
manat...@hotmail.com
Jan 10, 2012, 3:28:54 AM1/10/12
to
On Jan 10, 3:18 am, David Littlewood <da...@nospam.demon.co.uk> wrote:
> In article
> <ccb55263-f0f6-496f-9831-11b5246ce...@a40g2000vbu.googlegroups.com>,
> "manatba...@hotmail.com" <manatba...@hotmail.com> writes
nearly 30 years since I had to derive formulae like these.
Thank you for the correction, unlike a certain other poster who
described my description as "laughable" but didn't seem able to
correct the mistake.
MBQ
> In article
> <ccb55263-f0f6-496f-9831-11b5246ce...@a40g2000vbu.googlegroups.com>,
> "manatba...@hotmail.com" <manatba...@hotmail.com> writes
>
> >A further possibilty with a CDU is to build a voltage doubler into the
> >recharge circuit. The energy stored in a capacitor, and available to
> >deliver to the solenoid, is proportional to the voltage. Personally, I
> >would look at increasing the capacitance first since energy stored is
> >proportional to the square of the capacitance.
>
> No it isn't; E = 0.5CV^2. That is, proportional to voltage squared but
> only proportional to C.
Ooops! Trouble is everything is done in a spreadsheet these days. It's
> >A further possibilty with a CDU is to build a voltage doubler into the
> >recharge circuit. The energy stored in a capacitor, and available to
> >deliver to the solenoid, is proportional to the voltage. Personally, I
> >would look at increasing the capacitance first since energy stored is
> >proportional to the square of the capacitance.
>
> No it isn't; E = 0.5CV^2. That is, proportional to voltage squared but
> only proportional to C.
nearly 30 years since I had to derive formulae like these.
Thank you for the correction, unlike a certain other poster who
described my description as "laughable" but didn't seem able to
correct the mistake.
MBQ
Jeff
Jan 10, 2012, 4:50:05 AM1/10/12
to
>
> For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>
> Not sure if a CDU would actually make any difference, just alter
> when any problem might exist, whilst a CDU no doubt allows less
> power to be drawn /during/ the solenoid operation the same -if
> not greater- power is still consumed due to the CDU needing to
> recharge *after operation/discharge*.
that the peak current at any time can be low (depending on how quickly
you wish to re-activate the point motor).
Jeff
Jerry
Jan 10, 2012, 5:38:05 AM1/10/12
to
<manat...@hotmail.com> wrote in message
news:65114820-9f91-4dcb...@y2g2000yqk.googlegroups.com...
On Jan 10, 12:13 am, "Jerry" <mapson.sca...@btinternet.INVALID>
wrote:
> <manatba...@hotmail.com> wrote in message
>
<snip>
wrote:
> <manatba...@hotmail.com> wrote in message
>
: > I do thanks, unlike you, your description of a CDU,
: > which is laughable.
:
: Lets hear yours, if you think you can do better.
:
: Here's a good walk-through
http://home.cogeco.ca/~rpaisley4/CDPSU.html
: where you will see that any sensible CDU design
: includes the current limit on the recharge side. This
Does it, looks to me that it limits current draw on the recharge
: Lets hear yours, if you think you can do better.
:
: Here's a good walk-through
http://home.cogeco.ca/~rpaisley4/CDPSU.html
: where you will see that any sensible CDU design
: includes the current limit on the recharge side. This
side *when the CDU is discharging*, thus protecting the
recharging side from possible overload.
: limits the *power* but allows the capacitor to charge
: to almost the full voltage (hence the same *energy*
: stored).
A CDU has to recharge in seconds, that is because the next
: stored).
operation could (and probably will) be in seconds, the larger the
CDU is (thus the more work it can do, either bigger or a greater
number of solenoids) the MORE current it will draw during this
recharging phase -from the power bus in this case- and as the
OP's problem appears to be a lack of available amps...
All a CDU is designed to do, to use a figure of speech, is to
give a "good kick up the arse" to the solenoid - it is not
designed to limit power draw during recharging because that is
not the point of the unit, or shouldn't be...
<snip>
: > Next you'll be suggesting perpetual motion...
:
: Why would I need to do that?
Because that is what you are suggesting, clue there is no such
: Why would I need to do that?
thing as a free lunch, if you double the voltage, you need to
double the current as there is little point in having mega volts
but no amps [1], think about it... One of the reasons why the
national grid distributes at a HIGH volts/watts and then converts
down to *lower* volts/watts (ultimately to 240v, typically, for
UK domestic use), have it your way -with your magical "voltage
doubler"- and the national grid would distribute the street level
supply @ ~ 110v and then up-convert to 240v at the intake of the
end user.
It could be done but it would actually be more dangerous, one of
the reasons why the USA use duel phases @ 110v (with a centre tap
return) to allow the provision of a SP 220v high power supply for
cookers. water heaters etc.
[1] clue, it's the amps that do the work, not the volts...
<snip>
: If you know someone who is a member of MERG then get
: them to show you the schematic for the CAN_ACC4, a
: voltage doubling CDU.
You're missing the point MBQ, but no surprise there, yes these
: voltage doubling CDU.
units exist but they actually draw more current *for the same
work*, OR, draw the same current but do less work.
Anyway, I've never liked CDU's, better to simply use a high
current (amps) common power supply and suitable switching, either
directly or -better still- via relays [2] with smaller low
current control switches on the control board
[2] that then also allows interlocking to be deployed if one
wishes).
--
Regards, Jerry.
Jeff
Jan 10, 2012, 6:18:32 AM1/10/12
to
> <snip>
> :> I do thanks, unlike you, your description of a CDU,
> :> which is laughable.
> :
> : Lets hear yours, if you think you can do better.
> :
> : Here's a good walk-through
> http://home.cogeco.ca/~rpaisley4/CDPSU.html
> : where you will see that any sensible CDU design
> : includes the current limit on the recharge side. This
>
> Does it, looks to me that it limits current draw on the recharge
> side *when the CDU is discharging*, thus protecting the
> recharging side from possible overload.
This type of CDU is only of any use at all if there is significant
voltage drop in the wiring to the point motor when it operates, or the
power supply is not up to supplying the full current required by the
motor. Otherwise after initial switch on the capacitor does nothing useful.
> : limits the *power* but allows the capacitor to charge
> : to almost the full voltage (hence the same *energy*
> : stored).
>
> A CDU has to recharge in seconds, that is because the next
> operation could (and probably will) be in seconds, the larger the
> CDU is (thus the more work it can do, either bigger or a greater
> number of solenoids) the MORE current it will draw during this
> recharging phase -from the power bus in this case- and as the
> OP's problem appears to be a lack of available amps...
resistance of the motor. As long as there is sufficient energy in the
capacitor to throw the point a larger capacitor will be no better, other
than being able to throw another motor without re-charging.
>
> All a CDU is designed to do, to use a figure of speech, is to
> give a "good kick up the arse" to the solenoid - it is not
> designed to limit power draw during recharging because that is
> not the point of the unit, or shouldn't be...
> <snip>
> :> Next you'll be suggesting perpetual motion...
> :
> : Why would I need to do that?
>
> Because that is what you are suggesting, clue there is no such
> thing as a free lunch, if you double the voltage, you need to
> double the current as there is little point in having mega volts
> but no amps [1], think about it... One of the reasons why the
> national grid distributes at a HIGH volts/watts and then converts
> down to *lower* volts/watts (ultimately to 240v, typically, for
> UK domestic use), have it your way -with your magical "voltage
> doubler"- and the national grid would distribute the street level
> supply @ ~ 110v and then up-convert to 240v at the intake of the
> end user.
the motor (Ohm's Law), that will kick it harder. Because of the short
pulse the motor is not overheated by the higher voltage.
Regards
Jeff
Jerry
Jan 10, 2012, 7:14:35 AM1/10/12
to
"Jeff" <je...@jsystems.com> wrote in message
news:jeh6qc$5r1$1...@speranza.aioe.org...
:
: > <snip>
: > :> I do thanks, unlike you, your description of a CDU,
: > :> which is laughable.
: > :
: > : Lets hear yours, if you think you can do better.
: > :
: > : Here's a good walk-through
: > http://home.cogeco.ca/~rpaisley4/CDPSU.html
: > : where you will see that any sensible CDU design
: > : includes the current limit on the recharge side. This
: >
: > Does it, looks to me that it limits current draw on the
recharge
: > side *when the CDU is discharging*, thus protecting the
: > recharging side from possible overload.
:
: Doesn't that amount to the same thing!!!!!!
No, and you seem to have a sticky key on your keyboard.
: > :> which is laughable.
: > :
: > : Lets hear yours, if you think you can do better.
: > :
: > : Here's a good walk-through
: > http://home.cogeco.ca/~rpaisley4/CDPSU.html
: > : where you will see that any sensible CDU design
: > : includes the current limit on the recharge side. This
: >
: > Does it, looks to me that it limits current draw on the
recharge
: > side *when the CDU is discharging*, thus protecting the
: > recharging side from possible overload.
:
: Doesn't that amount to the same thing!!!!!!
:
: This type of CDU is only of any use at all if there is
significant
: voltage drop in the wiring to the point motor when it operates,
or the
: power supply is not up to supplying the full current required
by the
: motor. Otherwise after initial switch on the capacitor does
nothing useful.
:
Thus it would be bloody useless on a layout were one might be
: voltage drop in the wiring to the point motor when it operates,
or the
: power supply is not up to supplying the full current required
by the
: motor. Otherwise after initial switch on the capacitor does
nothing useful.
:
operating multiple numbers of solenoids, sometimes simultaneously
(via a route setting matrix for example) and at other times
sequentially - the latter being the more usual.
:
:
: > : limits the *power* but allows the capacitor to charge
: > : to almost the full voltage (hence the same *energy*
: > : stored).
: >
: > A CDU has to recharge in seconds, that is because the next
: > operation could (and probably will) be in seconds, the larger
the
: > CDU is (thus the more work it can do, either bigger or a
greater
: > number of solenoids) the MORE current it will draw during
this
: > recharging phase -from the power bus in this case- and as the
: > OP's problem appears to be a lack of available amps...
:
: No, the amount of current drawn will be dependant entirely on
the series
: resistance of the motor. As long as there is sufficient energy
in the
: capacitor to throw the point a larger capacitor will be no
better, other
: than being able to throw another motor without re-charging.
Exactly, so unless the capasitor is overly large the unit must
: > : stored).
: >
: > A CDU has to recharge in seconds, that is because the next
: > operation could (and probably will) be in seconds, the larger
the
: > CDU is (thus the more work it can do, either bigger or a
greater
: > number of solenoids) the MORE current it will draw during
this
: > recharging phase -from the power bus in this case- and as the
: > OP's problem appears to be a lack of available amps...
:
: No, the amount of current drawn will be dependant entirely on
the series
: resistance of the motor. As long as there is sufficient energy
in the
: capacitor to throw the point a larger capacitor will be no
better, other
: than being able to throw another motor without re-charging.
charge quickly, or the next operation might not happen, these
units are not about limitting current draw during charging but
current avalible during discharge.
:
: >
: > All a CDU is designed to do, to use a figure of speech, is to
: > give a "good kick up the arse" to the solenoid - it is not
: > designed to limit power draw during recharging because that
is
: > not the point of the unit, or shouldn't be...
:
: Yes, it must otherwise you will overload the psu.
Which, unless one designs the unit not to (as mentioned below, in
: > designed to limit power draw during recharging because that
is
: > not the point of the unit, or shouldn't be...
:
: Yes, it must otherwise you will overload the psu.
which case the solenoid will fail to operate and the unit will be
prevented from recharging) that is exactly what will happen if
the power supply or the unit is not of sufficient capacity, A CDU
is no substitute for an inadequate PSU!
:
:
: > <snip>
: > :> Next you'll be suggesting perpetual motion...
: > :
: > : Why would I need to do that?
: >
: > Because that is what you are suggesting, clue there is no
such
: > thing as a free lunch, if you double the voltage, you need to
: > double the current as there is little point in having mega
volts
: > but no amps [1], think about it... One of the reasons why the
: > national grid distributes at a HIGH volts/watts and then
converts
: > down to *lower* volts/watts (ultimately to 240v, typically,
for
: > UK domestic use), have it your way -with your magical
"voltage
: > doubler"- and the national grid would distribute the street
level
: > supply @ ~ 110v and then up-convert to 240v at the intake of
the
: > end user.
:
: You miss the point doubling the voltage will double the current
through
: the motor (Ohm's Law), that will kick it harder. Because of the
short
: pulse the motor is not overheated by the higher voltage.
:
: > :
: > : Why would I need to do that?
: >
: > Because that is what you are suggesting, clue there is no
such
: > thing as a free lunch, if you double the voltage, you need to
: > double the current as there is little point in having mega
volts
: > but no amps [1], think about it... One of the reasons why the
: > national grid distributes at a HIGH volts/watts and then
converts
: > down to *lower* volts/watts (ultimately to 240v, typically,
for
: > UK domestic use), have it your way -with your magical
"voltage
: > doubler"- and the national grid would distribute the street
level
: > supply @ ~ 110v and then up-convert to 240v at the intake of
the
: > end user.
:
: You miss the point doubling the voltage will double the current
through
: the motor (Ohm's Law), that will kick it harder. Because of the
short
: pulse the motor is not overheated by the higher voltage.
No, I get the whys and wherefores thanks, what I'm saying is that
in doing so (stepping-up) you need to increase the input current
used, always far more efficient (power use wise) to step-down.
It would actually make more sense for these point solenoids to be
made to work at a (continuous rating) of ~ 6 to 8 volts and then
power them for short periods at 12 to 16 volts, without any need
for a CDU.
manat...@hotmail.com
Jan 10, 2012, 7:45:53 AM1/10/12
to
On Jan 10, 10:38 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> : Here's a good walk-throughhttp://home.cogeco.ca/~rpaisley4/CDPSU.html
charging current to a reasonable level".
A better example would be http://www.merg.org.uk/merg_resources/dcc/download/acc2bsch.pdf
where you can see the classic two transistor current limit circuit.
> : limits the *power* but allows the capacitor to charge
> : to almost the full voltage (hence the same *energy*
> : stored).
>
> A CDU has to recharge in seconds, that is because the next
> operation could (and probably will) be in seconds,
Stating the obvious.
> the larger the
> CDU is (thus the more work it can do, either bigger or a greater
> number of solenoids) the MORE current it will draw during this
> recharging phase -from the power bus in this case- and as the
> OP's problem appears to be a lack of available amps...
The amount of current it draws during the recharge phase is under
control of the CDU designer. It's total charge that matters, which is
proprtional to both current and time.
> All a CDU is designed to do, to use a figure of speech, is to
> give a "good kick up the arse" to the solenoid - it is not
Yes, it is designed to discharge very quickly into a low impedance
load such as a solenoid point motor. That discharge takes of the order
of milliseconds.
> designed to limit power draw during recharging because that is
> not the point of the unit, or shouldn't be...
The whole point of a CDU is to buffer the main supply from these very
large, but brief current pulses. To give a "discharge" that could not
be supplied by the main supply. A *well designed one* does that by
recharging more slowly.
As an example A few amps for a few milliseconds into the solenoid can
be replaced by recharging in a few tens of milliseconds (10x the time)
at a few hundred milliamps (1/10 current).
> <snip>
> : > Next you'll be suggesting perpetual motion...
> :
> : Why would I need to do that?
>
> Because that is what you are suggesting,
No it iosn't. You really do need to go back to basic theory.
> clue there is no such
> thing as a free lunch, if you double the voltage, you need to
> double the current as there is little point in having mega volts
> but no amps [1], think about it... One of the reasons why the
Doubling the voltage in the charging circuit quadruples the energy
stored in the capacitor so you can give an even bigger kick to the
solenoid. The discharge current will initially be double due to simple
application of ohms law. The charging current and charging time are,
again, under control of the designer.
> national grid distributes at a HIGH volts/watts and then converts
> down to *lower* volts/watts (ultimately to 240v, typically, for
> UK domestic use), have it your way -with your magical "voltage
> doubler"- and the national grid would distribute the street level
> supply @ ~ 110v and then up-convert to 240v at the intake of the
> end user.
Completely different, and irrelevant to this discussion, scenario.
High voltage is used in the grid to reduce resistive losses.
> It could be done but it would actually be more dangerous, one of
> the reasons why the USA use duel phases @ 110v (with a centre tap
> return) to allow the provision of a SP 220v high power supply for
> cookers. water heaters etc.
WTF has this got to do with CDUs and point motors?
>
> [1] clue, it's the amps that do the work, not the volts...
>
> <snip>
> : If you know someone who is a member of MERG then get
> : them to show you the schematic for the CAN_ACC4, a
> : voltage doubling CDU.
>
> You're missing the point MBQ, but no surprise there, yes these
> units exist but they actually draw more current *for the same
> work*, OR, draw the same current but do less work.
Or vary the recharge time.
MBQ
> : Here's a good walk-throughhttp://home.cogeco.ca/~rpaisley4/CDPSU.html
> : where you will see that any sensible CDU design
> : includes the current limit on the recharge side. This
>
> Does it, looks to me that it limits current draw on the recharge
> side *when the CDU is discharging*, thus protecting the
> recharging side from possible overload.
Look at the "current blocking" design "A resistor to limit the maximum
> : includes the current limit on the recharge side. This
>
> Does it, looks to me that it limits current draw on the recharge
> side *when the CDU is discharging*, thus protecting the
> recharging side from possible overload.
charging current to a reasonable level".
A better example would be http://www.merg.org.uk/merg_resources/dcc/download/acc2bsch.pdf
where you can see the classic two transistor current limit circuit.
> : limits the *power* but allows the capacitor to charge
> : to almost the full voltage (hence the same *energy*
> : stored).
>
> A CDU has to recharge in seconds, that is because the next
> operation could (and probably will) be in seconds,
> the larger the
> CDU is (thus the more work it can do, either bigger or a greater
> number of solenoids) the MORE current it will draw during this
> recharging phase -from the power bus in this case- and as the
> OP's problem appears to be a lack of available amps...
control of the CDU designer. It's total charge that matters, which is
proprtional to both current and time.
> All a CDU is designed to do, to use a figure of speech, is to
> give a "good kick up the arse" to the solenoid - it is not
load such as a solenoid point motor. That discharge takes of the order
of milliseconds.
> designed to limit power draw during recharging because that is
> not the point of the unit, or shouldn't be...
large, but brief current pulses. To give a "discharge" that could not
be supplied by the main supply. A *well designed one* does that by
recharging more slowly.
As an example A few amps for a few milliseconds into the solenoid can
be replaced by recharging in a few tens of milliseconds (10x the time)
at a few hundred milliamps (1/10 current).
> <snip>
> : > Next you'll be suggesting perpetual motion...
> :
> : Why would I need to do that?
>
> Because that is what you are suggesting,
> clue there is no such
> thing as a free lunch, if you double the voltage, you need to
> double the current as there is little point in having mega volts
> but no amps [1], think about it... One of the reasons why the
stored in the capacitor so you can give an even bigger kick to the
solenoid. The discharge current will initially be double due to simple
application of ohms law. The charging current and charging time are,
again, under control of the designer.
> national grid distributes at a HIGH volts/watts and then converts
> down to *lower* volts/watts (ultimately to 240v, typically, for
> UK domestic use), have it your way -with your magical "voltage
> doubler"- and the national grid would distribute the street level
> supply @ ~ 110v and then up-convert to 240v at the intake of the
> end user.
High voltage is used in the grid to reduce resistive losses.
> It could be done but it would actually be more dangerous, one of
> the reasons why the USA use duel phases @ 110v (with a centre tap
> return) to allow the provision of a SP 220v high power supply for
> cookers. water heaters etc.
>
> [1] clue, it's the amps that do the work, not the volts...
>
> <snip>
> : If you know someone who is a member of MERG then get
> : them to show you the schematic for the CAN_ACC4, a
> : voltage doubling CDU.
>
> You're missing the point MBQ, but no surprise there, yes these
> units exist but they actually draw more current *for the same
> work*, OR, draw the same current but do less work.
MBQ
manat...@hotmail.com
Jan 10, 2012, 7:53:41 AM1/10/12
to
On Jan 10, 11:18 am, Jeff <j...@jsystems.com> wrote:
> > <snip>
> > :> I do thanks, unlike you, your description of a CDU,
> > :> which is laughable.
> > :
> > : Lets hear yours, if you think you can do better.
> > :
> > : Here's a good walk-through
> >http://home.cogeco.ca/~rpaisley4/CDPSU.html
> > : where you will see that any sensible CDU design
> > : includes the current limit on the recharge side. This
>
> > Does it, looks to me that it limits current draw on the recharge
> > side *when the CDU is discharging*, thus protecting the
> > recharging side from possible overload.
>
> Doesn't that amount to the same thing!!!!!!
Not quite, it also limits the recharge current.
> > <snip>
> > :> I do thanks, unlike you, your description of a CDU,
> > :> which is laughable.
> > :
> > : Lets hear yours, if you think you can do better.
> > :
> > : Here's a good walk-through
> >http://home.cogeco.ca/~rpaisley4/CDPSU.html
> > : where you will see that any sensible CDU design
> > : includes the current limit on the recharge side. This
>
> > Does it, looks to me that it limits current draw on the recharge
> > side *when the CDU is discharging*, thus protecting the
> > recharging side from possible overload.
>
> Doesn't that amount to the same thing!!!!!!
> This type of CDU is only of any use at all if there is significant
> voltage drop in the wiring to the point motor when it operates, or the
> power supply is not up to supplying the full current required by the
> motor.
> Otherwise after initial switch on the capacitor does nothing useful.
limited so it is less likely you will burn out a point motor; Once
discharged the current flowing is limited and you will minimise damage
to the switch contact when breaking the current flow [1].
MBQ
[1] Connecting a solenoid to a power supply through a switch means
that the full current determined by the solenoid coil resistance all
the while the swutch remains closed. This is a DC current. Breaking
the current by opening the switch leads to arcing between the swicth
contacts which damages the contacts. Given the cheapskate nature of a
lot of modellers I can guarantee many people are using switches that
are not really up to the job.
manat...@hotmail.com
Jan 10, 2012, 8:18:05 AM1/10/12
to
On Jan 10, 12:14 pm, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
>
> Exactly, so unless the capasitor is overly large the unit must
> charge quickly, or the next operation might not happen, these
The capacitor is discharged through the solenoid, *very* quickly,
>
> Exactly, so unless the capasitor is overly large the unit must
> charge quickly, or the next operation might not happen, these
regardless of its size. The recharge will still be quick, even if it
is an order of magnitude or more slower than the discharge time.
> units are not about limitting current draw during charging but
> current avalible during discharge.
supply connected to a capacitor connected through a switch to a
solenoid. What do you think happens when you close the switch?
>
> :
> : >
> : > All a CDU is designed to do, to use a figure of speech, is to
> : > give a "good kick up the arse" to the solenoid - it is not
> : > designed to limit power draw during recharging because that
> is
> : > not the point of the unit, or shouldn't be...
> :
> : Yes, it must otherwise you will overload the psu.
>
> Which, unless one designs the unit not to (as mentioned below, in
> which case the solenoid will fail to operate and the unit will be
> prevented from recharging) that is exactly what will happen if
> the power supply or the unit is not of sufficient capacity, A CDU
> is no substitute for an inadequate PSU!
Think of a how a toilet flush works. The cistern fills relatively
slowly. Flush, and it empties very quickly to wash the turds away.
Wait for it to refill, repeat...
The flush lever is the point operating switch. The cistern is the
capacitor. The turds are the point blades. The sudden deluge of water
is the current pulse through the solenoid. The inlet is your
"inadequate" PSU. Oh, hang on, so long as you don't need a s**t more
often than the cistern can fill then it's perfectly adequate.
MBQ
Jerry
Jan 10, 2012, 9:11:44 AM1/10/12
to
<manat...@hotmail.com> wrote in message
news:b28cb4f3-f13b-4713...@q17g2000yqh.googlegroups.com...
On Jan 10, 10:38 am, "Jerry" <mapson.sca...@btinternet.INVALID>
wrote:
<snip>
wrote:
: > Does it, looks to me that it limits current draw on
: > the recharge side *when the CDU is discharging*,
: > thus protecting the recharging side from possible
: > overload.
:
: Look at the "current blocking" design "A resistor to
: limit the maximum charging current to a reasonable
: level".
:
: A better example would be
http://www.merg.org.uk/merg_resources/dcc/download/acc2bsch.pdf
: where you can see the classic two transistor current limit
circuit.
So there is an alternate power path to by-pass the CDU should the
: > thus protecting the recharging side from possible
: > overload.
:
: Look at the "current blocking" design "A resistor to
: limit the maximum charging current to a reasonable
: level".
:
: A better example would be
http://www.merg.org.uk/merg_resources/dcc/download/acc2bsch.pdf
: where you can see the classic two transistor current limit
circuit.
capacitor(s) be discharged? By limiting the charging current one
also limits the total current draw through the unit at all times
and thus acts as overload protection. A CDU doesn't need a
'trickle' charge, it needs to recharge as quickly as possible,
ready for the next operation (or should do if of decent design).
<snip>
: > A CDU has to recharge in seconds, that is because
: > the next operation could (and probably will) be in
: > seconds,
:
: Stating the obvious.
So why do you claim otherwise, with your 'trickle charge' effect!
: > seconds,
:
: Stating the obvious.
<snip>
: The amount of current it draws during the recharge
: phase is under control of the CDU designer. It's total
: charge that matters, which is proprtional to both
: current and time.
No, only time is in the hands of the designer, current is a fixed
: charge that matters, which is proprtional to both
: current and time.
known, and unless you are prepared to allow the unit to fail
completely due to no fail back should the capacitor be discharged
even time isn't really in the designers hands ('time' is governed
by the track plan and or control panel design).
<snip most of MBQs ignorance>
: The whole point of a CDU is to buffer the main supply
: from these very large, but brief current pulses.
Utter claptrap. A CDU is not like a cars ignition system, it's
more like the cetral locking system, think about it....
> <snip>
: You really do need to go back to basic theory.
Stop talking about yourself MBQ, you do not have a clue as to how
and why a CDU is used/works.
: Doubling the voltage in the charging circuit quadruples the
: energy stored in the capacitor so you can give an even
: biggerkick to the solenoid.
Yes, but you don't get that effect for free, which is the point,
the OP doesn't have the spare amps to use in that way.
: The discharge current will initially be double due to
: simple application of ohms law.
No one is disagreeing about the discharge or current provided.
: The charging current and charging time are, again,
: under control of the designer.
Again, only time is, assuming s/he is willing to trade
reliability and/or usability.
: > national grid distributes at a HIGH volts/watts and
: > then converts down to *lower* volts/watts (ultimately
: > to 240v, typically, for
:
: > to 240v, typically, for
: Completely different, and irrelevant to this discussion,
: scenario. High voltage is used in the grid to reduce
: resistive losses.
Not at all irrelevant, to your claims that one can step-up
: resistive losses.
voltage/current without penalty.
: > It could be done but it would actually be more dangerous,
: > one of the reasons why the USA use duel phases @ 110v
: > (with a centre tap return) to allow the provision of a SP
: > 220v high power supply for cookers. water heaters etc.
:
: WTF has this got to do with CDUs and point motors?
It doesn't, directly, it was in reply to your claim that one can
: > (with a centre tap return) to allow the provision of a SP
: > 220v high power supply for cookers. water heaters etc.
:
: WTF has this got to do with CDUs and point motors?
magically get more current from using less, if that was possible
don't you think that every electricity utility company in the
world would be doing so! Lets use another example, most older CRT
TVs and computer monitors have very high power consumption
figures, not because the electronics on the PCB need such a
supply but because the CRT needs a high voltage/current supply
that is produced by stepping-up the input 240v supply, you seem
to be claiming that one could design a CRT PSU that provides the
same constant high current output power supply but which draws a
very much lower current on the intake side - no doubt you have
also been out to another one of your free lunchs today...
<snip>
: > You're missing the point MBQ, but no surprise there,
: > yes these units exist but they actually draw more
: > current *for the same work*, OR, draw the same
: > current but do less work.
:
: Or vary the recharge time.
Only if you trade reliability/usability, I want to be able to
: > current *for the same work*, OR, draw the same
: > current but do less work.
:
: Or vary the recharge time.
switch more than a couple of points sequentially at a time, as do
most I suspect! Yes your suggestion might work in a route setting
matrix, given a suitably large CDU but even then one would have
to wait before switching the next route!...
--
Regards, Jerry.
Jerry
Jan 10, 2012, 10:11:43 AM1/10/12
to
<manat...@hotmail.com> wrote in message
news:c5541653-6b54-401f...@o9g2000yqa.googlegroups.com...
On Jan 10, 12:14 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
wrote:
<snip>
wrote:
: > [Exactly, so unless the capasitor is overly large
: > the unit must charge quickly, or the next
: > operation might not happen, these]
: > units are not about limitting current draw during
: > charging but current avalible during discharge.
:
: If you have no current limit circuitry then all you have
: is a power supply connected to a capacitor connected
: through a switch to a solenoid. What do you think
: happens when you close the switch?
If you had a PSU of sufficient power you wouldn't need to have a
:
: If you have no current limit circuitry then all you have
: is a power supply connected to a capacitor connected
: through a switch to a solenoid. What do you think
: happens when you close the switch?
capacitor in the circuit, well not connected as in a CDU, so your
point (pun not intended) is what, exactly.
: > A CDU is no substitute for an inadequate PSU!
:
: Bingo! That's *exactly* what a CDU is for.
Oh right, so you are now claiming a solenoid can't work without a
: Bingo! That's *exactly* what a CDU is for.
CDU?! Duh, you really are a dimshit MBQ, perhaps if you took your
nose away from Google and actually did some modelling for a
change...
I have been at this game for the last 40+ odd years kiddo, never
have I used a CDU when powering such solenoids, although I have
also never used the same PSU as the traction current is obtained
from, especially the sort of model railway PSU common way back
when CDUs started to be used...
--
Regards, Jerry.
manat...@hotmail.com
Jan 10, 2012, 11:20:13 AM1/10/12
to
On Jan 10, 3:11 pm, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
were so over specced (compared to what could be used with a CDU) to
the extent that it could power a solenoid once a second, say.
> : > A CDU is no substitute for an inadequate PSU!
> :
> : Bingo! That's *exactly* what a CDU is for.
>
> Oh right, so you are now claiming a solenoid can't work without a
> CDU?! Duh, you really are a dimshit MBQ,
Don't try putting words in my mouth. I'm claiming that a CDU allows
the use of a power supply that would otherwise be inadequate to switch
a solenoid motor. It's quite a simple concept
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:c5541653-6b54-401f...@o9g2000yqa.googlegroups.com...
> On Jan 10, 12:14 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > [Exactly, so unless the capasitor is overly large
> : > the unit must charge quickly, or the next
> : > operation might not happen, these]
> : > units are not about limitting current draw during
> : > charging but current avalible during discharge.
> :
> : If you have no current limit circuitry then all you have
> : is a power supply connected to a capacitor connected
> : through a switch to a solenoid. What do you think
> : happens when you close the switch?
>
> If you had a PSU of sufficient power you wouldn't need to have a
> capacitor in the circuit, well not connected as in a CDU, so your
> point (pun not intended) is what, exactly.
The point is that we would not be discussing CDUs if the power supply
> news:c5541653-6b54-401f...@o9g2000yqa.googlegroups.com...
> On Jan 10, 12:14 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > [Exactly, so unless the capasitor is overly large
> : > the unit must charge quickly, or the next
> : > operation might not happen, these]
> : > units are not about limitting current draw during
> : > charging but current avalible during discharge.
> :
> : If you have no current limit circuitry then all you have
> : is a power supply connected to a capacitor connected
> : through a switch to a solenoid. What do you think
> : happens when you close the switch?
>
> If you had a PSU of sufficient power you wouldn't need to have a
> capacitor in the circuit, well not connected as in a CDU, so your
> point (pun not intended) is what, exactly.
were so over specced (compared to what could be used with a CDU) to
the extent that it could power a solenoid once a second, say.
> : > A CDU is no substitute for an inadequate PSU!
> :
> : Bingo! That's *exactly* what a CDU is for.
>
> Oh right, so you are now claiming a solenoid can't work without a
> CDU?! Duh, you really are a dimshit MBQ,
the use of a power supply that would otherwise be inadequate to switch
a solenoid motor. It's quite a simple concept
MBQ
Jeff
Jan 10, 2012, 11:34:07 AM1/10/12
to
On 10/01/2012 12:14, Jerry wrote:
> "Jeff"<je...@jsystems.com> wrote in message
> news:jeh6qc$5r1$1...@speranza.aioe.org...
> :
> :> <snip>
> :> :> I do thanks, unlike you, your description of a CDU,
> :> :> which is laughable.
> :> :
> :> : Lets hear yours, if you think you can do better.
> :> :
> :> : Here's a good walk-through
> :> http://home.cogeco.ca/~rpaisley4/CDPSU.html
> :> : where you will see that any sensible CDU design
> :> : includes the current limit on the recharge side. This
> :>
> :> Does it, looks to me that it limits current draw on the
> recharge
> :> side *when the CDU is discharging*, thus protecting the
> :> recharging side from possible overload.
> :
> : Doesn't that amount to the same thing!!!!!!
>
> No, and you seem to have a sticky key on your keyboard.
My keyboard is working pewrfectly !!!!!!!!!!!!!
> "Jeff"<je...@jsystems.com> wrote in message
> news:jeh6qc$5r1$1...@speranza.aioe.org...
> :
> :> <snip>
> :> :> I do thanks, unlike you, your description of a CDU,
> :> :> which is laughable.
> :> :
> :> : Lets hear yours, if you think you can do better.
> :> :
> :> : Here's a good walk-through
> :> http://home.cogeco.ca/~rpaisley4/CDPSU.html
> :> : where you will see that any sensible CDU design
> :> : includes the current limit on the recharge side. This
> :>
> :> Does it, looks to me that it limits current draw on the
> recharge
> :> side *when the CDU is discharging*, thus protecting the
> :> recharging side from possible overload.
> :
> : Doesn't that amount to the same thing!!!!!!
>
> No, and you seem to have a sticky key on your keyboard.
snip>
> Exactly, so unless the capasitor is overly large the unit must
> charge quickly, or the next operation might not happen, these
> units are not about limitting current draw during charging but
> current avalible during discharge.
>
>
No, you are missing the point, if there is little resistance in the wire
> charge quickly, or the next operation might not happen, these
> units are not about limitting current draw during charging but
> current avalible during discharge.
>
>
and the psu is capable of supplying the peak current required then a CDU
will not improve things.
If that is not the case and, for example there is significant wiring
resistance, then you could just add the capacitor without the series
resistor. As long as the wiring between the resistor and the motor is
*short & low resistance* you will see the same effect as having the
resistor there *except that there will be a large inrush current to
re-charge the capacitor, which will be limited only by the wiring
resistance and the psu o/p capability.
You example of throwing multiple points from one of this type of CDU is
a red herring since for one CDU to operate many points the wiring from
the CDU to the points *must* be low resistance and because of multiple
points it cannot be close to all of them. So you might as well throw
away the CDU and just make sure that you have low resistance and a psu
that can provide the peak current.
Of course the above does not apply if the CDU runs a higher voltage that
the normal rating of the motor, and provides a short pulse at a higher
voltage. In that case more series resistance can be tolerated.
:
> :>
> :> All a CDU is designed to do, to use a figure of speech, is to
> :> give a "good kick up the arse" to the solenoid - it is not
> :> designed to limit power draw during recharging because that
> is
> :> not the point of the unit, or shouldn't be...
> :
> : Yes, it must otherwise you will overload the psu.
>
> Which, unless one designs the unit not to (as mentioned below, in
> which case the solenoid will fail to operate and the unit will be
> prevented from recharging) that is exactly what will happen if
> the power supply or the unit is not of sufficient capacity, A CDU
> is no substitute for an inadequate PSU!
>
> :
> :
> :> <snip>
> :
> :> designed to limit power draw during recharging because that
> is
> :> not the point of the unit, or shouldn't be...
> :
> : Yes, it must otherwise you will overload the psu.
>
> Which, unless one designs the unit not to (as mentioned below, in
> which case the solenoid will fail to operate and the unit will be
> prevented from recharging) that is exactly what will happen if
> the power supply or the unit is not of sufficient capacity, A CDU
> is no substitute for an inadequate PSU!
>
> :
> :
> :> <snip>
> :
> : You miss the point doubling the voltage will double the current
> through
> : the motor (Ohm's Law), that will kick it harder. Because of the
> short
> : pulse the motor is not overheated by the higher voltage.
> :
>
> No, I get the whys and wherefores thanks, what I'm saying is that
> in doing so (stepping-up) you need to increase the input current
> used, always far more efficient (power use wise) to step-down.
No exactly the opposite if you are talking about DC, stepping down
> through
> : the motor (Ohm's Law), that will kick it harder. Because of the
> short
> : pulse the motor is not overheated by the higher voltage.
> :
>
> No, I get the whys and wherefores thanks, what I'm saying is that
> in doing so (stepping-up) you need to increase the input current
> used, always far more efficient (power use wise) to step-down.
normally wastes the excess voltage as heat, very inefficient, unless you
use some form of switching regulator. If you are talking about AC & a
transformer, or voltage doubler, there is no significant penalty as
conservation of energy applies, less any small transformer loss, whether
you are stepping up or stepping down.
>
> It would actually make more sense for these point solenoids to be
> made to work at a (continuous rating) of ~ 6 to 8 volts and then
> power them for short periods at 12 to 16 volts, without any need
> for a CDU.
pulse!!!!!!
Regards
Jeff
Jeff
Jan 10, 2012, 11:36:06 AM1/10/12
to
Jeff
manat...@hotmail.com
Jan 10, 2012, 11:42:00 AM1/10/12
to
On Jan 10, 2:11 pm, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
> By limiting the charging current one
> also limits the total current draw through the unit at all times
> and thus acts as overload protection. A CDU doesn't need a
> 'trickle' charge, it needs to recharge as quickly as possible,
> ready for the next operation (or should do if of decent design).
I wouldn't call it a trickle charge. The circuit is designed so that
the current is sufficient to recharge the capacitor in time for the
next operation. That minimum re-use time will be a design parameter.
> <snip>
> : > A CDU has to recharge in seconds, that is because
> : > the next operation could (and probably will) be in
> : > seconds,
> :
> : Stating the obvious.
>
> So why do you claim otherwise, with your 'trickle charge' effect!
I don't. All I have claimed is that the recharge time can be longer
than the discharge time. It will still "recharge in seconds".
Use of "trickle charge" is *your* terminolgy. It suggests too low a
recharge current, to me, so I don't use that term.
> <snip>
> : The amount of current it draws during the recharge
> : phase is under control of the CDU designer. It's total
> : charge that matters, which is proprtional to both
> : current and time.
>
> No, only time is in the hands of the designer, current is a fixed
> known, and unless you are prepared to allow the unit to fail
Charge or discharge current? Fixed by whom?
> completely due to no fail back should the capacitor be discharged
> even time isn't really in the designers hands ('time' is governed
> by the track plan and or control panel design).
The time before the CDU can be used again is a design parameter, and
needs to be less than the time between operator interaction with the
control panel. Once that is determined you can calculate the maximum
charge current required in order to ensure the CDU is recharged
sufficiently quickly.
> <snip most of MBQs ignorance>
> : The whole point of a CDU is to buffer the main supply
> : from these very large, but brief current pulses.
>
> Utter claptrap. A CDU is not like a cars ignition system,
So why bring it up?
> it's
> more like the cetral locking system, think about it....
That's claptrap.
> > <snip>
>
> : You really do need to go back to basic theory.
>
> Stop talking about yourself MBQ, you do not have a clue as to how
> and why a CDU is used/works.
LOL!
> : Doubling the voltage in the charging circuit quadruples the
> : energy stored in the capacitor so you can give an even
> : biggerkick to the solenoid.
>
> Yes, but you don't get that effect for free, which is the point,
> the OP doesn't have the spare amps to use in that way.
By this point the discussion had moved on to a general discussion of
CDU operation. The OPs situation is not relevant to that discussion.
It's called thread drift.
> : The discharge current will initially be double due to
> : simple application of ohms law.
>
> No one is disagreeing about the discharge or current provided.
>
> : The charging current and charging time are, again,
> : under control of the designer.
>
> Again, only time is, assuming s/he is willing to trade
> reliability and/or usability.
>
> : > national grid distributes at a HIGH volts/watts and
> : > then converts down to *lower* volts/watts (ultimately
> : > to 240v, typically, for
> :
> : Completely different, and irrelevant to this discussion,
> : scenario. High voltage is used in the grid to reduce
> : resistive losses.
>
> Not at all irrelevant, to your claims that one can step-up
> voltage/current without penalty.
I made no such claim. [see below]
> : > It could be done but it would actually be more dangerous,
> : > one of the reasons why the USA use duel phases @ 110v
> : > (with a centre tap return) to allow the provision of a SP
> : > 220v high power supply for cookers. water heaters etc.
> :
> : WTF has this got to do with CDUs and point motors?
>
> It doesn't, directly, it was in reply to your claim that one can
> magically get more current from using less, if that was possible
Again, I made no such claim. I claimed you can get more *energy* in
the discharge pulse by charging the capacitor to a higher voltage. The
higher voltage will result in a higher discharge current (simple ohms
law). There will be penalties in the form of changes to the required
current and/or charge time.
If you are so clever, do a SPICE simulation of a voltage doubling CDU
and see how it works.
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:b28cb4f3-f13b-4713...@q17g2000yqh.googlegroups.com...
> On Jan 10, 10:38 am, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > Does it, looks to me that it limits current draw on
> : > the recharge side *when the CDU is discharging*,
> : > thus protecting the recharging side from possible
> : > overload.
> :
> : Look at the "current blocking" design "A resistor to
> : limit the maximum charging current to a reasonable
> : level".
> :
> : A better example would behttp://www.merg.org.uk/merg_resources/dcc/download/acc2bsch.pdf
> news:b28cb4f3-f13b-4713...@q17g2000yqh.googlegroups.com...
> On Jan 10, 10:38 am, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > Does it, looks to me that it limits current draw on
> : > the recharge side *when the CDU is discharging*,
> : > thus protecting the recharging side from possible
> : > overload.
> :
> : Look at the "current blocking" design "A resistor to
> : limit the maximum charging current to a reasonable
> : level".
> :
> : where you can see the classic two transistor current limit
> circuit.
>
> So there is an alternate power path to by-pass the CDU should the
> capacitor(s) be discharged?
Correct, nor does there need to be.
> circuit.
>
> So there is an alternate power path to by-pass the CDU should the
> capacitor(s) be discharged?
> By limiting the charging current one
> also limits the total current draw through the unit at all times
> and thus acts as overload protection. A CDU doesn't need a
> 'trickle' charge, it needs to recharge as quickly as possible,
> ready for the next operation (or should do if of decent design).
the current is sufficient to recharge the capacitor in time for the
next operation. That minimum re-use time will be a design parameter.
> <snip>
> : > A CDU has to recharge in seconds, that is because
> : > the next operation could (and probably will) be in
> : > seconds,
> :
> : Stating the obvious.
>
> So why do you claim otherwise, with your 'trickle charge' effect!
than the discharge time. It will still "recharge in seconds".
Use of "trickle charge" is *your* terminolgy. It suggests too low a
recharge current, to me, so I don't use that term.
> <snip>
> : The amount of current it draws during the recharge
> : phase is under control of the CDU designer. It's total
> : charge that matters, which is proprtional to both
> : current and time.
>
> No, only time is in the hands of the designer, current is a fixed
> known, and unless you are prepared to allow the unit to fail
> completely due to no fail back should the capacitor be discharged
> even time isn't really in the designers hands ('time' is governed
> by the track plan and or control panel design).
needs to be less than the time between operator interaction with the
control panel. Once that is determined you can calculate the maximum
charge current required in order to ensure the CDU is recharged
sufficiently quickly.
> <snip most of MBQs ignorance>
> : The whole point of a CDU is to buffer the main supply
> : from these very large, but brief current pulses.
>
> Utter claptrap. A CDU is not like a cars ignition system,
> it's
> more like the cetral locking system, think about it....
> > <snip>
>
> : You really do need to go back to basic theory.
>
> Stop talking about yourself MBQ, you do not have a clue as to how
> and why a CDU is used/works.
> : Doubling the voltage in the charging circuit quadruples the
> : energy stored in the capacitor so you can give an even
> : biggerkick to the solenoid.
>
> Yes, but you don't get that effect for free, which is the point,
> the OP doesn't have the spare amps to use in that way.
CDU operation. The OPs situation is not relevant to that discussion.
It's called thread drift.
> : The discharge current will initially be double due to
> : simple application of ohms law.
>
> No one is disagreeing about the discharge or current provided.
>
> : The charging current and charging time are, again,
> : under control of the designer.
>
> Again, only time is, assuming s/he is willing to trade
> reliability and/or usability.
>
> : > national grid distributes at a HIGH volts/watts and
> : > then converts down to *lower* volts/watts (ultimately
> : > to 240v, typically, for
> :
> : Completely different, and irrelevant to this discussion,
> : scenario. High voltage is used in the grid to reduce
> : resistive losses.
>
> Not at all irrelevant, to your claims that one can step-up
> voltage/current without penalty.
> : > It could be done but it would actually be more dangerous,
> : > one of the reasons why the USA use duel phases @ 110v
> : > (with a centre tap return) to allow the provision of a SP
> : > 220v high power supply for cookers. water heaters etc.
> :
> : WTF has this got to do with CDUs and point motors?
>
> It doesn't, directly, it was in reply to your claim that one can
> magically get more current from using less, if that was possible
the discharge pulse by charging the capacitor to a higher voltage. The
higher voltage will result in a higher discharge current (simple ohms
law). There will be penalties in the form of changes to the required
current and/or charge time.
If you are so clever, do a SPICE simulation of a voltage doubling CDU
and see how it works.
MBQ
Jeff
Jan 10, 2012, 11:51:30 AM1/10/12
to
>> If you had a PSU of sufficient power you wouldn't need to have a
>> capacitor in the circuit, well not connected as in a CDU, so your
>> point (pun not intended) is what, exactly.
>
> The point is that we would not be discussing CDUs if the power supply
> were so over specced (compared to what could be used with a CDU) to
> the extent that it could power a solenoid once a second, say.
it is the peak current capability that is the limiting factor; and how
much the voltage sags when you try to draw excess current. PSUs will
recover to their full o/p pretty much instantly once the load is removed.
>
>> :> A CDU is no substitute for an inadequate PSU!
>> :
>> : Bingo! That's *exactly* what a CDU is for.
>>
>> Oh right, so you are now claiming a solenoid can't work without a
>> CDU?! Duh, you really are a dimshit MBQ,
>
> Don't try putting words in my mouth. I'm claiming that a CDU allows
> the use of a power supply that would otherwise be inadequate to switch
> a solenoid motor. It's quite a simple concept
That is correct in as far as it goes, but a CDU will still fail if there
>> : Bingo! That's *exactly* what a CDU is for.
>>
>> Oh right, so you are now claiming a solenoid can't work without a
>> CDU?! Duh, you really are a dimshit MBQ,
>
> Don't try putting words in my mouth. I'm claiming that a CDU allows
> the use of a power supply that would otherwise be inadequate to switch
> a solenoid motor. It's quite a simple concept
is significant resistance between it and the motor. All a capacitor is
doing is effectively reducing the output impedance of the source, but
only for a very short period. Once discharged it will present a low
impedance to the psu, and without any current limiting will initially
look pretty much like a short circuit to the psu. Add to that the fact
that capacitors do not like large inrush currents; that is why you will
find ripple ratings on capacitors.
Jeff
Jeff
Jan 10, 2012, 11:55:05 AM1/10/12
to
>
>> By limiting the charging current one
>> also limits the total current draw through the unit at all times
>> and thus acts as overload protection. A CDU doesn't need a
>> 'trickle' charge, it needs to recharge as quickly as possible,
>> ready for the next operation (or should do if of decent design).
>
> I wouldn't call it a trickle charge. The circuit is designed so that
> the current is sufficient to recharge the capacitor in time for the
> next operation. That minimum re-use time will be a design parameter.
design parameter if you want the capacitor to last any length of time.
Jeff
manat...@hotmail.com
Jan 10, 2012, 11:58:58 AM1/10/12
to
MBQ
manat...@hotmail.com
Jan 10, 2012, 11:58:26 AM1/10/12
to
On Jan 10, 4:51 pm, Jeff <j...@jsystems.com> wrote:
> >> If you had a PSU of sufficient power you wouldn't need to have a
> >> capacitor in the circuit, well not connected as in a CDU, so your
> >> point (pun not intended) is what, exactly.
>
> > The point is that we would not be discussing CDUs if the power supply
> > were so over specced (compared to what could be used with a CDU) to
> > the extent that it could power a solenoid once a second, say.
>
> The rate at which you switch with just a psu is pretty much irrelevant,
> it is the peak current capability that is the limiting factor; and how
> much the voltage sags when you try to draw excess current. PSUs will
> recover to their full o/p pretty much instantly once the load is removed.
>
>
>
> >> :> A CDU is no substitute for an inadequate PSU!
> >> :
> >> : Bingo! That's *exactly* what a CDU is for.
>
> >> Oh right, so you are now claiming a solenoid can't work without a
> >> CDU?! Duh, you really are a dimshit MBQ,
>
> > Don't try putting words in my mouth. I'm claiming that a CDU allows
> > the use of a power supply that would otherwise be inadequate to switch
> > a solenoid motor. It's quite a simple concept
>
> That is correct in as far as it goes, but a CDU will still fail if there
> is significant resistance between it and the motor.
I think it was my comment about requiring the wiring to be "as thick
> >> If you had a PSU of sufficient power you wouldn't need to have a
> >> capacitor in the circuit, well not connected as in a CDU, so your
> >> point (pun not intended) is what, exactly.
>
> > The point is that we would not be discussing CDUs if the power supply
> > were so over specced (compared to what could be used with a CDU) to
> > the extent that it could power a solenoid once a second, say.
>
> The rate at which you switch with just a psu is pretty much irrelevant,
> it is the peak current capability that is the limiting factor; and how
> much the voltage sags when you try to draw excess current. PSUs will
> recover to their full o/p pretty much instantly once the load is removed.
>
>
>
> >> :> A CDU is no substitute for an inadequate PSU!
> >> :
> >> : Bingo! That's *exactly* what a CDU is for.
>
> >> Oh right, so you are now claiming a solenoid can't work without a
> >> CDU?! Duh, you really are a dimshit MBQ,
>
> > Don't try putting words in my mouth. I'm claiming that a CDU allows
> > the use of a power supply that would otherwise be inadequate to switch
> > a solenoid motor. It's quite a simple concept
>
> That is correct in as far as it goes, but a CDU will still fail if there
> is significant resistance between it and the motor.
and short as possible" that set Jerry off on one :-)
Before he starts again, it was a turn of phrase, there are obviously
pragmatic limits to "thick" and "short" for each individual
installation. To some extent two two can be traded off.
> All a capacitor is
> doing is effectively reducing the output impedance of the source, but
> only for a very short period. Once discharged it will present a low
> impedance to the psu, and without any current limiting will initially
> look pretty much like a short circuit to the psu. Add to that the fact
> that capacitors do not like large inrush currents; that is why you will
> find ripple ratings on capacitors.
MBQ
Jerry
Jan 10, 2012, 12:31:25 PM1/10/12
to
<manat...@hotmail.com> wrote in message
news:07bf5daa-235b-465f...@ck5g2000vbb.googlegroups.com...
<snip>
: The point is that we would not be discussing CDUs if
: the power supply were so over specced (compared to
: what could be used with a CDU) to the extent that it
: could power a solenoid once a second, say.
But most dedicated PSU's could, it is your design of CDU that
: what could be used with a CDU) to the extent that it
: could power a solenoid once a second, say.
can't do that, you just don't get do you, to much Googling and
not enough real world experience is your problem, not helped by
people who wish to play with electronics (as fun as that can be)
more than they actually want top play with model trains. The
problem the OP has is that his PSU can barely supply enough power
for the locos never mind anything else, your idea of a CDU would
actually make his problems worse because it would prolong the
periods of inadequate supply, unless you care to explain were all
this 'free energy' is coming from that you keep whitening on
about.
The OP would have been as well to have ordered a stand alone PSU
(and built a control panel) for his accessories as buy a
different DCC system, other than the fact that he is well advised
to move away from the basic (trainset) end of the DCC market.
<snip>
: Don't try putting words in my mouth. I'm claiming that
You don't seem to know what you are claiming, that's the problem!
: a CDU allows the use of a power supply that would
: otherwise be inadequate to switch a solenoid motor.
: It's quite a simple concept
Indeed it is, you need a PSU that is adequate to power the
: It's quite a simple concept
solenoid regardless of if a CDU is fitted, period.
--
Regards, Jerry.
Jane Sullivan
Jan 10, 2012, 12:45:24 PM1/10/12
to
On 10/01/2012 16:58, manat...@hotmail.com wrote:
> On Jan 10, 4:51 pm, Jeff<j...@jsystems.com> wrote:
> I think it was my comment about requiring the wiring to be "as thick
> and short as possible" that set Jerry off on one :-)
>
> Before he starts again, it was a turn of phrase, there are obviously
> pragmatic limits to "thick" and "short" for each individual
> installation. To some extent two two can be traded off.
I can think of a turn of phrase involving "thick" and "short" that
> On Jan 10, 4:51 pm, Jeff<j...@jsystems.com> wrote:
> I think it was my comment about requiring the wiring to be "as thick
> and short as possible" that set Jerry off on one :-)
>
> Before he starts again, it was a turn of phrase, there are obviously
> pragmatic limits to "thick" and "short" for each individual
> installation. To some extent two two can be traded off.
applies to some individuals.
--
Jane
manat...@hotmail.com
Jan 10, 2012, 1:10:21 PM1/10/12
to
On Jan 10, 5:31 pm, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
The point you are missing is that what is that "adequate" changes when
you use a CDU.
Assume 4 ohms for the solenoid coil resistance. Assume a PSU of 16V.
That requires a PSU rated at 4 Amps to drive the solenoid directly,
unless you deliberately overload the PSU each time you fire point
motor.
With a CDU you could easily limit the charge current to 2A and use a
lower rated PSU.
MBQ
> <manatba...@hotmail.com> wrote in message
you use a CDU.
Assume 4 ohms for the solenoid coil resistance. Assume a PSU of 16V.
That requires a PSU rated at 4 Amps to drive the solenoid directly,
unless you deliberately overload the PSU each time you fire point
motor.
With a CDU you could easily limit the charge current to 2A and use a
lower rated PSU.
MBQ
simon
Jan 10, 2012, 5:31:27 PM1/10/12
to
Perhaps of more interest to the OP, I have 2 peco point motors throwing 2
peco points from a single output of a hornby accessory controller connected
to a Select. No problem with points changing. Another point (yep), by
connecting points that are likely to be changed on a single route to
different accessory controllers there is less work for any single
controller.
Finally is a few seconds between point changes that important - lets face it
how long did it take a real signalman to set up a route ?
Cheers,
Simon
peco points from a single output of a hornby accessory controller connected
to a Select. No problem with points changing. Another point (yep), by
connecting points that are likely to be changed on a single route to
different accessory controllers there is less work for any single
controller.
Finally is a few seconds between point changes that important - lets face it
how long did it take a real signalman to set up a route ?
Cheers,
Simon
manat...@hotmail.com
Jan 11, 2012, 3:46:19 AM1/11/12
to
On Jan 10, 10:31 pm, "simon" <nos...@nospam.com> wrote:
> Perhaps of more interest to the OP, I have 2 peco point motors throwing 2
> peco points from a single output of a hornby accessory controller connected
> to a Select. No problem with points changing. Another point (yep), by
Sounds like the Hornby unit is well designed. Does it take power from
> Perhaps of more interest to the OP, I have 2 peco point motors throwing 2
> peco points from a single output of a hornby accessory controller connected
> to a Select. No problem with points changing. Another point (yep), by
the track or a separate input?
> connecting points that are likely to be changed on a single route to
> different accessory controllers there is less work for any single
> controller.
> Finally is a few seconds between point changes that important - lets face it
> how long did it take a real signalman to set up a route ?
spend more time modelling the real thing than playing with
electronics.
MBQ
Jerry
Jan 11, 2012, 5:09:09 AM1/11/12
to
<manat...@hotmail.com> wrote in message
news:7d90747b-32e4-4dca...@h13g2000vbn.googlegroups.com...
<snip>
: I think it was my comment about requiring the wiring to
: be "as thick and short as possible" that set Jerry off on
: one :-)
No, it's your utter ignorance which does that, and your continual
: one :-)
refusal to accept that you are wrong -hence why you chose to take
a cheap shot at me- rather than to address the points made by
Jeff.
Oh well, as they say, none so blind as those who chose not to
see...
--
Regards, Jerry.
Jerry
Jan 11, 2012, 5:23:49 AM1/11/12
to
<manat...@hotmail.com> wrote in message
news:4f84ed24-8d36-4302...@z19g2000vbe.googlegroups.com...
<snip>
: The point you are missing is that what is that "adequate"
: changes when you use a CDU.
Err, MBQ, you are missing is the *fact* that it does not, as even
Jeff has pointed out, and indeed a CDU can actually make problems
worse.
--
Regards, Jerry.
Jerry
Jan 11, 2012, 5:55:01 AM1/11/12
to
news:jehpa2$jrc$1...@speranza.aioe.org...
<snip>
: You example of throwing multiple points from one of this type
CDUs became popular in the 1960s, it had nothing what so ever to
do with wiring size as most people routinely used wire more than
adequate for the task, it was to (try to) prevent solenoid
burn-outs due to poorly laid and/or 'sticky' points -hence my
previous comment about giving the solenoid a "kick up the arse"-
and as you point out to add some protection to the coil windings
should the power continue to be feed to the coil due to the unit
not throwing over.
<snip>
:
: No exactly the opposite if you are talking about DC, stepping
they will love that revolutionary discovery! Free, or at least
paid for, lunches all round...
:
: >
: > It would actually make more sense for these point solenoids
Indeed, and no CDU in sight, except that most trainsets/layouts
do not have a 24v supply, hence the suggestion of 6 to 8V coils.
--
Regards, Jerry.
<snip>
: You example of throwing multiple points from one of this type
of CDU is
: a red herring since for one CDU to operate many points the
wiring from
: the CDU to the points *must* be low resistance and because of
multiple
: points it cannot be close to all of them. So you might as well
throw
: away the CDU and just make sure that you have low resistance
and a psu
: that can provide the peak current.
Err, I think that *was* my point! Lets get back the basics of why
: a red herring since for one CDU to operate many points the
wiring from
: the CDU to the points *must* be low resistance and because of
multiple
: points it cannot be close to all of them. So you might as well
throw
: away the CDU and just make sure that you have low resistance
and a psu
: that can provide the peak current.
CDUs became popular in the 1960s, it had nothing what so ever to
do with wiring size as most people routinely used wire more than
adequate for the task, it was to (try to) prevent solenoid
burn-outs due to poorly laid and/or 'sticky' points -hence my
previous comment about giving the solenoid a "kick up the arse"-
and as you point out to add some protection to the coil windings
should the power continue to be feed to the coil due to the unit
not throwing over.
<snip>
:
: No exactly the opposite if you are talking about DC, stepping
down
: normally wastes the excess voltage as heat, very inefficient,
unless you
: use some form of switching regulator. If you are talking about
AC & a
: transformer, or voltage doubler, there is no significant
penalty as
: conservation of energy applies, less any small transformer
loss, whether
: you are stepping up or stepping down.
Best you tell that to the electric utility companies then mate,
: normally wastes the excess voltage as heat, very inefficient,
unless you
: use some form of switching regulator. If you are talking about
AC & a
: transformer, or voltage doubler, there is no significant
penalty as
: conservation of energy applies, less any small transformer
loss, whether
: you are stepping up or stepping down.
they will love that revolutionary discovery! Free, or at least
paid for, lunches all round...
:
: >
: > It would actually make more sense for these point solenoids
to be
: > made to work at a (continuous rating) of ~ 6 to 8 volts and
then
: > power them for short periods at 12 to 16 volts, without any
need
: > for a CDU.
:
: That is no different to them operating at 12 or 18V and using
24V
: pulse!!!!!!
:
: > made to work at a (continuous rating) of ~ 6 to 8 volts and
then
: > power them for short periods at 12 to 16 volts, without any
need
: > for a CDU.
:
: That is no different to them operating at 12 or 18V and using
24V
: pulse!!!!!!
Indeed, and no CDU in sight, except that most trainsets/layouts
do not have a 24v supply, hence the suggestion of 6 to 8V coils.
--
Regards, Jerry.
Jerry
Jan 11, 2012, 6:12:49 AM1/11/12
to
<manat...@hotmail.com> wrote in message
news:425a5071-8fc7-4fda...@h12g2000yqg.googlegroups.com...
On Jan 10, 2:11 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
wrote:
<snip>
wrote:
: > So there is an alternate power path to by-pass the CDU
: > should the capacitor(s) be discharged?
:
: Correct, nor does there need to be.
If you accept the in-service failures!
:
: Correct, nor does there need to be.
As Jeff pointed out, a PSU will recover instantly...
manat...@hotmail.com
Jan 11, 2012, 6:58:07 AM1/11/12
to
On Jan 11, 11:12 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
about recharge times being fast enough.
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:425a5071-8fc7-4fda...@h12g2000yqg.googlegroups.com...
> On Jan 10, 2:11 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > So there is an alternate power path to by-pass the CDU
> : > should the capacitor(s) be discharged?
> :
> : Correct, nor does there need to be.
>
> If you accept the in-service failures!
Which in service failures are they? You are still missing the point
> news:425a5071-8fc7-4fda...@h12g2000yqg.googlegroups.com...
> On Jan 10, 2:11 pm, "Jerry" <mapson.sca...@btinternet.INVALID>
> wrote:
>
> <snip>
> : > So there is an alternate power path to by-pass the CDU
> : > should the capacitor(s) be discharged?
> :
> : Correct, nor does there need to be.
>
> If you accept the in-service failures!
about recharge times being fast enough.
MBQ
manat...@hotmail.com
Jan 11, 2012, 7:01:15 AM1/11/12
to
On Jan 11, 10:23 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
I'll let others read the rest of that post, that you snipped, and come
to their own conclusions.
MBQ
> <manatba...@hotmail.com> wrote in message
to their own conclusions.
MBQ
manat...@hotmail.com
Jan 11, 2012, 7:00:03 AM1/11/12
to
On Jan 11, 10:55 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> "Jeff" <j...@jsystems.com> wrote in message
>
> news:jehpa2$jrc$1...@speranza.aioe.org...
> : No exactly the opposite if you are talking about DC, stepping
> down
> : normally wastes the excess voltage as heat, very inefficient,
> unless you
> : use some form of switching regulator. If you are talking about
> AC & a
> : transformer, or voltage doubler, there is no significant
> penalty as
> : conservation of energy applies, less any small transformer
> loss, whether
> : you are stepping up or stepping down.
>
> Best you tell that to the electric utility companies then mate,
Thay already understand the issues perfectly well.
> they will love that revolutionary discovery! Free, or at least
> paid for, lunches all round...
Nothing Jeff says violates any laws of physics.
Exactly which bit do you have a problem with?
Maybe we can help.
MBQ
> "Jeff" <j...@jsystems.com> wrote in message
>
> news:jehpa2$jrc$1...@speranza.aioe.org...
> : No exactly the opposite if you are talking about DC, stepping
> down
> : normally wastes the excess voltage as heat, very inefficient,
> unless you
> : use some form of switching regulator. If you are talking about
> AC & a
> : transformer, or voltage doubler, there is no significant
> penalty as
> : conservation of energy applies, less any small transformer
> loss, whether
> : you are stepping up or stepping down.
>
> Best you tell that to the electric utility companies then mate,
> they will love that revolutionary discovery! Free, or at least
> paid for, lunches all round...
Exactly which bit do you have a problem with?
Maybe we can help.
MBQ
manat...@hotmail.com
Jan 11, 2012, 7:05:53 AM1/11/12
to
On Jan 11, 10:09 am, "Jerry" <mapson.sca...@btinternet.INVALID> wrote:
> <manatba...@hotmail.com> wrote in message
with him.
> Oh well, as they say, none so blind as those who chose not to
> see...
Talking about yourself again, Jerry.
MBQ
> <manatba...@hotmail.com> wrote in message
>
> news:7d90747b-32e4-4dca...@h13g2000vbn.googlegroups.com...
>
> <snip>
> : I think it was my comment about requiring the wiring to
> : be "as thick and short as possible" that set Jerry off on
> : one :-)
>
> No, it's your utter ignorance which does that, and your continual
> refusal to accept that you are wrong -hence why you chose to take
> a cheap shot at me- rather than to address the points made by
> Jeff.
I don't need to address the points made by Jeff, as I am in agreement
> news:7d90747b-32e4-4dca...@h13g2000vbn.googlegroups.com...
>
> <snip>
> : I think it was my comment about requiring the wiring to
> : be "as thick and short as possible" that set Jerry off on
> : one :-)
>
> No, it's your utter ignorance which does that, and your continual
> refusal to accept that you are wrong -hence why you chose to take
> a cheap shot at me- rather than to address the points made by
> Jeff.
with him.
> Oh well, as they say, none so blind as those who chose not to
> see...
MBQ
Jeff
Jan 11, 2012, 8:21:05 AM1/11/12
to
> <snip>
> :
> : No exactly the opposite if you are talking about DC, stepping
> down
> : normally wastes the excess voltage as heat, very inefficient,
> unless you
> : use some form of switching regulator. If you are talking about
> : transformer, or voltage doubler, there is no significant
> penalty as
> : conservation of energy applies, less any small transformer
> loss, whether
> : you are stepping up or stepping down.
>
> Best you tell that to the electric utility companies then mate,
> they will love that revolutionary discovery! Free, or at least
> paid for, lunches all round...
The electricity companies use the principle all the time, if it were not
> penalty as
> : conservation of energy applies, less any small transformer
> loss, whether
> : you are stepping up or stepping down.
>
> Best you tell that to the electric utility companies then mate,
> they will love that revolutionary discovery! Free, or at least
> paid for, lunches all round...
the case then there would be horrendous losses in the supply system.
Stepping the voltage up and down with transformers is essentially a
lossless process, apart from the small losses in the actual transformer
core.
The National Grid is stepped up to EHT voltages, up to 400kV, because
the resistive losses in the lines will be lower for a given power
consumption. However, the *POWER* will remain the same, and when the
EHT is stepped down to lower voltages the current will go up, *but* the
power will still remain the same, (less any losses in the transformers).
This works for both stepping up and stepping down in voltage, the
current changes but the power must remain the same due to conservation
of energy.
DC is a different matter as you can't use transformers, so in order to
step DC *UP* you must convert it to AC (as in a switching
regulator/psu). To step it down you can dump the excess voltage, but it
has to go somewhere, and that is in heat, as in a simple linear
regulator, or even a series resistor; or you can again use a more
efficient switching regulator.
When you step up to a higher voltage in a CDU the step up is not
'inefficient' the additional current is needed because you are putting
more current through the coil (for a short period), which is you aim in
order to make the point move quickly. There is no, or at least, very
little penalty in the transformation process itself.
The situation when you charge a CDU capacitor is entirely dependant on
the charging circuit. If you have a 12V supply & capacitor voltage you
need some series element to protect the psu from seeing a low impedance
as the capacitor discharges, and also to keep any recharge current
within the capabilities of the psu, & to prevent high in-rush currents
into the Cap. & to prevent a high continuous current into the coil.
If you step up to a higher voltage you either need a a higher voltage dc
psu, or some means of transforming a lower voltage up. An AC psu and
transformer would be the easiest, but a voltage doubler circuit would
do, but are generally capable of lower current outputs (which would
slow the re-charge time) and are somewhat more inefficient. A switch
mode regulator would be efficient but is more complex.
Either way you still need current limiting for the reasons given above.
If you pulse the motor at a higher voltage the peak current will be
higher through the coil (the whole point of the exercise), so more
energy will be taken from the cap, so for a recharge will either take
longer for a fixed input power or more power and a higher current will
be required, however, the transformation to the higher voltage is not
'inefficient', the higher current is required merely because you are
putting more current through the coil.
Regards
Jeff
simon
Jan 11, 2012, 7:10:25 PM1/11/12
to
<manat...@hotmail.com> wrote in message
news:154d6cb8-88ec-48ae...@z12g2000yqm.googlegroups.com...
On Jan 10, 10:31 pm, "simon" <nos...@nospam.com> wrote:
> Perhaps of more interest to the OP, I have 2 peco point motors throwing 2
> peco points from a single output of a hornby accessory controller
> connected
> to a Select. No problem with points changing. Another point (yep), by
Sounds like the Hornby unit is well designed. Does it take power from
the track or a separate input?
Has a seperate DC output but only one DCC, so same connection as track.
> Perhaps of more interest to the OP, I have 2 peco point motors throwing 2
> peco points from a single output of a hornby accessory controller
> connected
> to a Select. No problem with points changing. Another point (yep), by
Sounds like the Hornby unit is well designed. Does it take power from
the track or a separate input?
Cheers,
Simon
Chris
Jan 12, 2012, 1:40:53 PM1/12/12
to
On 09/01/2012 21:47, manat...@hotmail.com wrote:
>>
>> <snipped for brevity>
>> : Twin-coil solenoid point motors? These take a very
>> : large current. The wiring needs to be as thick and
>> : short as possible for best results.
>>
>> You really don't understand the relation between voltage drop,
>> distance and conductor size do you MBQ?!
>
> Yes I do, thank you, nice of you to ask.
>
>> What you wrote above
>> makes no sense what so ever, are you /really/ saying that you
>> would use say 4.0mm wire if the distance between the power source
>> and load was 300mm apart, because that is what you have implied.
>> OTOH you may well need to use a 10 mm solid busbar if your load
>> is 1000+ ft away!... :~)
>
> I would use wire appropriate to the situation. The point is that a
> solenoid point motor can take quite a few amps. Some people claim to
> get away with using cat5 wiring to connect them. I would use something
> rather thicker.
>
> In simple terms, thicker is better than thinner, shorter is better
> than longer.
>
> If the OP doesn't understand my point then hopefully he will come back
> for clarification.
>
>>
>> : Do the Hornby accessory decoders have a built in CDU?
>>
>> For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>>
>> Not sure if a CDU would actually make any difference, just alter
>> when any problem might exist, whilst a CDU no doubt allows less
>> power to be drawn /during/ the solenoid operation the same -if
>> not greater- power is still consumed due to the CDU needing to
>> recharge *after operation/discharge*.
>
> You need to understand the difference between power and energy. A CDU
> can deliver the neccessary high current pulse, over a short period of
> time, to fire a solenoid motor. It delivers a certain amount of energy
> into the load.
>
> A CDU is generally designed to recharge over a much longer period,
> drawing a much lower current. The energy is the same (plus any losses
> in the circuit). The much lower recharge current means that said CDU
> *might* be suitable to be powered from the DCC track bus without
> upsetting the system too much. With a 1 Amp power supply in the OPs I
> would say it's still marginal.
>
> A further possibilty with a CDU is to build a voltage doubler into the
> recharge circuit. The energy stored in a capacitor, and available to
> deliver to the solenoid, is proportional to the voltage. Personally, I
> would look at increasing the capacitance first since energy stored is
> proportional to the square of the capacitance.
>
> MBQ
>
You made a mistake in responding to the obvious troll :(
--
Chris
> On Jan 9, 8:54 pm, "Jerry"<mapson.sca...@btinternet.INVALID> wrote:
>> <manatba...@hotmail.com> wrote in message
>>
>> news:a3e8ebcc-5e95-4e56...@t30g2000vbx.googlegroups.com...
>> <manatba...@hotmail.com> wrote in message
>>
>>
>> <snipped for brevity>
>> : Twin-coil solenoid point motors? These take a very
>> : large current. The wiring needs to be as thick and
>> : short as possible for best results.
>>
>> You really don't understand the relation between voltage drop,
>> distance and conductor size do you MBQ?!
>
> Yes I do, thank you, nice of you to ask.
>
>> What you wrote above
>> makes no sense what so ever, are you /really/ saying that you
>> would use say 4.0mm wire if the distance between the power source
>> and load was 300mm apart, because that is what you have implied.
>> OTOH you may well need to use a 10 mm solid busbar if your load
>> is 1000+ ft away!... :~)
>
> I would use wire appropriate to the situation. The point is that a
> solenoid point motor can take quite a few amps. Some people claim to
> get away with using cat5 wiring to connect them. I would use something
> rather thicker.
>
> In simple terms, thicker is better than thinner, shorter is better
> than longer.
>
> If the OP doesn't understand my point then hopefully he will come back
> for clarification.
>
>>
>> : Do the Hornby accessory decoders have a built in CDU?
>>
>> For the benefit of the 'newbies', CDU = Capacitor Discharge Unit.
>>
>> Not sure if a CDU would actually make any difference, just alter
>> when any problem might exist, whilst a CDU no doubt allows less
>> power to be drawn /during/ the solenoid operation the same -if
>> not greater- power is still consumed due to the CDU needing to
>> recharge *after operation/discharge*.
>
> You need to understand the difference between power and energy. A CDU
> can deliver the neccessary high current pulse, over a short period of
> time, to fire a solenoid motor. It delivers a certain amount of energy
> into the load.
>
> A CDU is generally designed to recharge over a much longer period,
> drawing a much lower current. The energy is the same (plus any losses
> in the circuit). The much lower recharge current means that said CDU
> *might* be suitable to be powered from the DCC track bus without
> upsetting the system too much. With a 1 Amp power supply in the OPs I
> would say it's still marginal.
>
> A further possibilty with a CDU is to build a voltage doubler into the
> recharge circuit. The energy stored in a capacitor, and available to
> deliver to the solenoid, is proportional to the voltage. Personally, I
> would look at increasing the capacitance first since energy stored is
> proportional to the square of the capacitance.
>
> MBQ
>
You made a mistake in responding to the obvious troll :(
--
Chris
Chris
Jan 12, 2012, 1:56:22 PM1/12/12
to
do a similar job as the CDU does for the modeller so that when a route
is set all the points can move at the same time, at least on Southern
where I worked on the S&T.
For my fiddle yard I use a CML DAC10 that allows me use inputs to set
routes and allows you to adjust CDU pulse time for each motor and
recharge time afterwards so when I set a route I see the points
switching one after the other. It has Loconet interface for feedback to
controllers or computers connected to the network if you need that.
--
Chris
manat...@hotmail.com
Jan 12, 2012, 3:25:03 PM1/12/12
to
On Jan 12, 6:40 pm, Chris <nos...@nospam.com> wrote:
I'm too willing to give him the benefit of the doubt, and a chance to
prove he can change. It seems I was wrong again.
MBQ
prove he can change. It seems I was wrong again.
MBQ
Chris
Jan 12, 2012, 4:37:55 PM1/12/12
to
similar results. There are unfortunately a few people around like him
and in the extreme can effectively close down newsgroups.
--
Chris
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