Slot Car Power Supply
Darren DeCoste
power supply. He wants to be able to run either 18vdc or 22vdc. Does
anyone recommend a power supply or have the plans to build a power supply
that would be stable enough for 4 cars on the track. I am guessing around a
5amp supply is needed. Any help in this area would be appreciated.
Thank you,
Darren DeCoste
ddec...@midsouth.rr.com
hman
Donæ„’ go with to much Volts. It kills your motors.
Use something between 12 and 15 Volts but go with more Amps.
I use 13,7 Volts and 30 Amps.
Workæ„€ great.
Hans
Andrew Jones
the top, and the motors aren't designed for it. However, with regard 30
Amps, there is really no point to getting a power supply which is capable of
supplying so much. Any load draws as much current as it needs (I=V/R).
Electric motors draw the most at zero rpm, at which point I'll be surprised
if you find a single slotcar pulling more than 2Amps. Times four cars is 8
Amps.
I think that if you tried to draw 30 Amps, your power supply cables
would overheat and your throttles would sizzle! Brillian'!
Andrew Jones
>Don´t go with to much Volts. It kills your motors.
>Use something between 12 and 15 Volts but go with more Amps.
>I use 13,7 Volts and 30 Amps.
>Work´s great.
>Hans
sms
factor should be you wallet.
I have a 42A supply which I got cheap at a surplus sale.
With this I would be able to weld 1mm steel plates;-)
But That I have this available does not mean I use it all the
time.
A quick comparison with a 1:1 motor.
low down torque is equal to the voltage available
top end horsepower is equal to the current available.
I have yet to see or hear anybody using all the horsepowers
available continously;-)
Too much lowend torque an you rip the bearings to kingdome.......
I have measured (all issues with measurements apply;-)
that a super 16D takes approx 5A peak
a G15 almost 10A - but this is the peak value running around
a Blue King!
More than carbattery voltage (14,5 Volt) is not advisable.
I know that some of the original supplies is rated at 16V or so,
but this is rather sloppy supplies - by all means they work.
A 2CV is a car, a Mustang is a car;-)
and Carerra seems to be engineered to run at (good) 18V
Put all you money in current;-)
Morten
Raiders of the lost electron flow
My Slot Cars
Cheap and loads of power
Ernie
sms <sost...@online.nospam.no> wrote in message
news:RRZP4.2867$kF4....@news1.online.no...
Peter Zivanovic
<and...@icon.co.za> writes
> I agree with Hans, anything over, say, 16V is just getting a bit over
>the top, and the motors aren't designed for it. However, with regard 30
>Amps, there is really no point to getting a power supply which is capable of
>supplying so much. Any load draws as much current as it needs (I=V/R).
>Electric motors draw the most at zero rpm, at which point I'll be surprised
>if you find a single slotcar pulling more than 2Amps. Times four cars is 8
>Amps.
>
> I think that if you tried to draw 30 Amps, your power supply cables
>would overheat and your throttles would sizzle! Brillian'!
- so little chance of a fry-up. I agree, 30A seems a lot but I /think/
the reasons people like supplies with such excess capacity is so that
the odd spikes and surges inflicted on one car when another de-slots (or
whatever) are minimised.
Peter.
--
Peter Zivanovic
hman
> the reasons people like supplies with such excess capacity is so that
> the odd spikes and surges inflicted on one car when another de-slots (or
> whatever) are minimised.
>
> Peter.
>
> --
> Peter Zivanovic
Hans
Andrew Jones
electric theory which says that it will. Anyone?
Surely a well placed capacitor will be more usefull in controlling that
annoying effect.
On a side, I hope that all you good people, especially those with these
whopping 30 Amp plus supplies have a fuse close to the supply. An
accidental short could be quite unpleasant with so much current available.
Andrew Jones
>As you said, the likelihood of drawing much more than a few amps is low
>- so little chance of a fry-up. I agree, 30A seems a lot but I /think/
Andrew Jones
I'm sorry, what do you mean by 1:1 motor?
>low down torque is equal to the voltage available
Isn't it Voltage squared? (May be wrong on this).
>top end horsepower is equal to the current available.
I must disagree with this. Whether a 1 Amp motor is being powered by a car
battery, or a 1 Amp power supply with the same voltage, the top (and
bottom) end power is the same. The motor will draw the same current at the
same rpm.
Andrew Jones
KIM KLOSTER
Do you use the charger while running ?
Reg.
Kim Kloster
My Slot Cars skrev i meldingen <8epqr7$1mr$1...@starburst.uk.insnet.net>...
Peter Zivanovic
<and...@icon.co.za> writes
> Good point. But does it actually help that? I don't see anything in
>electric theory which says that it will. Anyone?
around limitations and impedances in the circuit which means transient
events affect the whole system.
> Surely a well placed capacitor will be more usefull in controlling that
>annoying effect.
Ah, but, a well placed capacitor will increase the voltage by 30%! I
suppose a very small one might be OK.
> On a side, I hope that all you good people, especially those with these
>whopping 30 Amp plus supplies have a fuse close to the supply. An
>accidental short could be quite unpleasant with so much current available.
Not half! I once put a meter lead on a small lead-acid battery. When I
had finished, I put the lead down - inadvertently shorting the battery.
It took about 2 seconds before I noticed the smell!
Peter.
--
Peter Zivanovic
pmartin
Even a bad battery and charger will do it.
"My Slot Cars" <myslo...@geocities.com> wrote in message
news:8epqr7$1mr$1...@starburst.uk.insnet.net...
> We use a 12v car battery and a charger,
>
> Cheap and loads of power
>
> Ernie
>
> www.geocities.com/myslotcars
>
>
> sms <sost...@online.nospam.no> wrote in message
> news:RRZP4.2867$kF4....@news1.online.no...
> > You cannot have a too powerful powersupply, the only limiting
> > factor should be you wallet.
> >
> > I have a 42A supply which I got cheap at a surplus sale.
> > With this I would be able to weld 1mm steel plates;-)
> > But That I have this available does not mean I use it all the
> > time.
> > A quick comparison with a 1:1 motor.
> > low down torque is equal to the voltage available
> > top end horsepower is equal to the current available.
Gregory Braun -- Software Design
A 5-10 ampere power supply should be sufficient for a four lane circuit. A
nice 0-30 VDC power supply is available on the Radio Shack web site. The
unit is not available in their stores though, so you'll need to order it
online.
I've used this unit and found it quite nice, an added bonus is that when
small children or our girlfriends and wives want to race I can reduce the
voltage to say 9-12 VDC which prevents the cars from flying off the track
and hitting the floor or a nearby wall.
A slot car motor will only draw the current it needs, so having a large
high-output power supply is never a problem. Do however install fuses in
each of the driver's stations to prevent burning up controllers that may be
attached incorrectly.
A DC motor by it's very nature has infinite resistance at stall. But once
the armature is turning it will draw very little current. Most better DC
power supplies include voltage and amperage metering so you can see for
yourself just how little a slot car motor really needs. Unless you're
running some pretty hairy armatures a 5 or 10 ampere supply will provide
plenty of power with a nice reserve.
As for battery power vs. a solid state power supply I prefer the power
supply method. Batteries are heavy and normally only produce 12-13.6 VDC, so
getting a working voltage of 18-22 VDC is troublesome. You can either strap
three 6 volt units together to make 18 volts, or use two 12 volt units to
create a 24 volt supply.
You'll also need a good charger and some way of venting the room that you
charge them in. The charging process produces Hydrogen gas as a byproduct
which is very dangerous in an enclosed area. Under the hood of a car is not
normally a problem because the engine bay is vented naturally as the car
moves down the road, but to charge a wet cell in an enclosed room is never a
good idea. One spark from a slot cat motor or a cigarette is all it takes!
If you do opt to go the wet cell/charger route never run your slot car
motors with the charger attached to the battery. The DC motors used in slot
cars will be damaged by the AC ripple found in most chargers. AC ripple will
not damage a battery but it's very hard on DC slot car motors.
Serious racers will often employ individual power supplies for each lane.
This will prevent power surges to adjacent lanes when another racer deslots.
I use this method on one of my larger layouts and find it works quite well.
If you decide to build a power supply you might consider designing a
multiple lane unit.
Radio Shack sells an 18 VAC transformer rated at 3 amperes for $9.95. You
could purchase four of them and the associated diode bridges and filtering
caps all for under $60.00 dollars.
An 18 VAC transformer will produce approximately 25 VDC with a full wave
diode bridge. You could get fancy and add four solid state voltage
regulators and still keep your costs below $75.00.
This would be the ideal solution, individually regulated supplies for each
lane with a power rating of 3 amperes for each car. No messy batteries and
chargers to worry about either. You'll pay at least $75.00 for wet cell
batteries and a good charger anyway.
Visit my web site at:
http://www.gregorybraun.com/slotcars
for more power supply information.
Best regards from Milwaukee, WI U.S.A.
Gregory Braun
E-Mail: Gregor...@CompuServe.com
Web Site: http://www.gregorybraun.com
Slot Cars: http://www.gregorybraun.com/slotcars
Telephone: 1.414.444.8497
-------------------------------------------------------
Ancient of days! august Athena! where,
Where are thy men of might? thy grand in soul?
Gone--glimmering through the dream of things that were.
--Byron
Jeff Vincent
<Gregor...@CompuServe.com> wrote:
<good stuff on wet-cell batteries and chargers clipped>
What would you think of a small gel-cell for a 1/32 track (two lane
Ninco)? The battery in question is 12 volts, 4.5 amp hours. It
should have sufficient power, and you don't have the charging dangers
of a wet-cell (and its nicely portable, as a bonus). My model rocket
club has one for launching models and I've considered getting one for
the track. The source was Doug Pratt at Pratt Rocketry, about $15-20
w/charger.
Jeff (the Ninco Newbie) Vincent
My Slot Cars
Use the charger while running keeps the battery topped up all the time,
We run high power 30.000 engined cars
and have no probs.
Ernie
pmartin <pma...@adelphia.net> wrote in message
news:HtrQ4.78$Xk5....@news2.news.adelphia.net...
std::cout
Software Design" <Gregor...@CompuServe.com> wrote:
>Darren,
>
>If you do opt to go the wet cell/charger route never run your
slot car
>motors with the charger attached to the battery. The DC motors
used in slot
>cars will be damaged by the AC ripple found in most chargers.
AC ripple will
>not damage a battery but it's very hard on DC slot car motors.
Mostly good information, but I believe the above quote is
incorrect. I asked on the sl...@topica.com list this question
of two Electrical Engineers, who happen to be avid slot car
racing fans. Their response was that running most homeset cars
*directly* on a decent quality manual charger was perfectly ok,
and that none of them in many years of racing homeset cars has
ever burned out a motor. They added that if I was afraid of
burning out my motors that I should wire a 12 volt
car/motorcycle battery in parallel - that it smooths out *all*
AC ripple. In fact, on the sci.electronics newsgroups I asked
the same question and got a response that a battery is one of
the most perfect capacitors available - more perfect for
generating a linear power supply curve than some of the best
linear power supplies.
Take it for what it is worth, but the basic idea that I got is
that people are *way* too concerned with Linear power supplies -
and that unless you are running really hot, custom wound motors,
that nothing detrimental will happen from using switching power
supplies, linear power supplies or a $50 Exide Battery charger
from K-Mart.
YMMV, but someone once said to me that this is not rocket
science, and that they were surprised that *anyone* ever got
started racing slot cars with all the mis-information and urban
legends passed around. :-)
p.s. Have you ever measured the ripple from a wall-wart? They
are not exactly the most linear supplies either, yet not too
many people have a problem running some pretty nice 1/32 and HO
cars on them.
* Sent from RemarQ http://www.remarq.com The Internet's Discussion Network *
The fastest and easiest way to search and participate in Usenet - Free!
Peter Zivanovic
>If you do opt to go the wet cell/charger route never run your slot car
>motors with the charger attached to the battery.
This may be good advice.
>The DC motors used in slot
>cars will be damaged by the AC ripple found in most chargers. AC ripple will
>not damage a battery but it's very hard on DC slot car motors.
I don't think this is right.
1) Most toy PSU's supply unsmoothed, rectified AC - in other words, the
waveform looks like a series of adjacent humps.
2) Some slot cars are designed to run on ac supplied to the rails but
with single diodes in line with the motor - the waveform looks like the
above but with each alternate "hump" removed.
3) Some Power supplies to RC car motors (I think) supply a square wave
with the maximum voltage being applied in very short bursts of shorter
or longer duration depending on the power you want to deliver.
Point 3 may be rubbish but I know 1 & 2 are correct and the motors run
fine in these circumstances.
Peter.
--
Peter Zivanovic
Brett C. Cammack
wrote:
> What would you think of a small gel-cell for a 1/32 track (two lane
>Ninco)? The battery in question is 12 volts, 4.5 amp hours. It
>should have sufficient power, and you don't have the charging dangers
>of a wet-cell (and its nicely portable, as a bonus). My model rocket
>club has one for launching models and I've considered getting one for
>the track. The source was Doug Pratt at Pratt Rocketry, about $15-20
>w/charger.
Check out www.bgmicro.com first. They've always got gel cells for
good prices. There's one similar to what you describe on their "Let's
Make a Deal" page.
Regards,
Brett C. Cammack
That's Racing! Motorsports
Pompano Beach, FL
Gregory Braun -- Software Design
A 4.5 Amp/Hour wet cell may be a bit small depending upon your intended
usage.
A 4.5 A/H cell would produce 4-1/2 ampere for one hour of racing, or 1
ampere for 4-1/2 hours etc.
You might find that the battery's power is depleted faster than the charger
can rejuvenate it. Why not look for something more in the 10-15 amp/hour
range. Or use a separate battery for each lane.
Another good source of batteries that will work are the type used in alarm
systems. These are often used as a backup system if the AC fails. Alarm
systems often have a battery charger permanently connected to trickle charge
the battery while not in use.
I use this same type of battery to power an infrared transmitter mounted on
a tripod next to a kart track. The transmitter is detected by receivers on
each racing kart when they pass the start/finish line to count laps and
record lap times.
This is a sealed lead/acid cell I think, but can be charged indoors without
the danger normally associated with regular wet cells.
E. Harris
in speed within a half an hour of beginning your races... You need a lot
more amp hours. Gobs. Like a car battery, but email me if you want to try
this as there are safety concerns you need to recognize.
Earl
retrotech50
Jeff Vincent wrote:
> On Fri, 5 May 2000 08:48:46 -0500, "Gregory Braun -- Software Design"
> <Gregor...@CompuServe.com> wrote:
>
> <good stuff on wet-cell batteries and chargers clipped>
>
> What would you think of a small gel-cell for a 1/32 track (two lane
> Ninco)? The battery in question is 12 volts, 4.5 amp hours. It
> should have sufficient power, and you don't have the charging dangers
> of a wet-cell (and its nicely portable, as a bonus). My model rocket
> club has one for launching models and I've considered getting one for
> the track. The source was Doug Pratt at Pratt Rocketry, about $15-20
> w/charger.
>
George Warner
<stuart.ha...@quinnipiac.edu.invalid> wrote:
> In article <3912d141$0$73...@news.execpc.com>, "Gregory Braun --
> Software Design" <Gregor...@CompuServe.com> wrote:
> >Darren,
> >
> > If you do opt to go the wet cell/charger route never run your
> > slot car motors with the charger attached to the battery. The
> > DC motors used in slot cars will be damaged by the AC ripple
> > found in most chargers. AC ripple will not damage a battery but
> > it's very hard on DC slot car motors.
>
I'm an electrical engineer and we drove this discussion into the
ground on a slot car BBS about a year ago. Here's a summary of
what we concluded.
AC ripple can be very hard on DC slot car motors. It can create
a great deal of excessive heating. It requires certain specific
real world conditions to occur so it can be deceiving but it is
real and a definite threat to motors.
Under the right conditions (which I will explain shortly) the
problem occurs when current flows in both directions in the motor.
The reverse current not only decelerates and heats the motor, it
causes the driver to compensate with more forward current to
maintain the desired speed which (in addition to creating more
heat), in turn, creates more reverse current, decelerating and
heat.
A DC motor performs as both a motor and a DC generator. As the
motor speeds up, the generator effect creates a reverse EMF (voltage)
which opposes the applied voltage. This is the voltage that limits
the top speed of the motor. If the applied voltage is reduced (even
for an instant as found in ripple), the generated voltage exceeds the
applied voltage and current flows in the reverse direction (under the
right conditions).
Here's the deceiving part. Cheap power supplies (such as a battery
charger) generally only rectify (using diodes) the output voltage.
They provide no filtering (capacitors) or regulation (electronic
devices). With a single slot car, these diodes actually prevent
this reverse current which causes the undue motor heating.
However, when you put a second (or more) cars on the track, the
scenario changes. The additional car(s) actually create a load
which allows current to now flow backward through motors during
the low points of the power supply voltage. Now, you get the
excessive heating. The motor that was cool as a cucumber in warm-up
is now on the verge of frying during a race.
The ripple issue is no urban legend. It is very real and can
be easily demonstrated. A battery charger is probably about the
worse supply you can use with a slot car. Wall-warts are not
very far behind. Batteries provide a smooth output but may not
provide the voltage you truly want and may be a little hazardous
in the home. Don't discount the value of a nice, regulated
power supply. One good one will last a lifetime.
Peter Zivanovic
<warn...@ptd.net> writes
An interesting and thought provoking post.
>I'm an electrical engineer
I'm not so please treat what I say more as enquiry than fact.
>and we drove this discussion into the
>ground on a slot car BBS about a year ago.
I can imagine!
>Here's a summary of
>what we concluded.
>AC ripple can be very hard on DC slot car motors. It can create
>a great deal of excessive heating. It requires certain specific
>real world conditions to occur so it can be deceiving but it is
>real and a definite threat to motors.
>Under the right conditions (which I will explain shortly) the
>problem occurs when current flows in both directions in the motor.
>The reverse current not only decelerates and heats the motor, it
>causes the driver to compensate with more forward current to
>maintain the desired speed which (in addition to creating more
>heat), in turn, creates more reverse current, decelerating and
>heat.
>A DC motor performs as both a motor and a DC generator. As the
>motor speeds up, the generator effect creates a reverse EMF (voltage)
>which opposes the applied voltage. This is the voltage that limits
>the top speed of the motor. If the applied voltage is reduced (even
>for an instant as found in ripple), the generated voltage exceeds the
>applied voltage and current flows in the reverse direction (under the
>right conditions).
OK.
>Here's the deceiving part. Cheap power supplies (such as a battery
>charger) generally only rectify (using diodes) the output voltage.
>They provide no filtering (capacitors) or regulation (electronic
>devices). With a single slot car, these diodes actually prevent
>this reverse current which causes the undue motor heating.
Right, with you so far. Just to clarify, the diodes prevent the reverse
current flowing - so there is no undue motor heating.
It's worth pointing out that were a supply to be smoothed with
capacitors, the voltage output by the supply will be boosted (I think by
a factor of up to 1.4). I think Ninco use this effect in their 10304
Power Booster.
>However, when you put a second (or more) cars on the track,
Just to clarify, do you mean when you are driving two or more cars from
one DC-output?
>the
>scenario changes. The additional car(s) actually create a load
>which allows current to now flow backward through motors during
>the low points of the power supply voltage. Now, you get the
>excessive heating. The motor that was cool as a cucumber in warm-up
>is now on the verge of frying during a race.
Some slot car manufacturers offer electrical accessories that are
powered by the same power supply as the car(s). Presumably these have
the same effect as another car would?
The way to overcome this would be to fit a diode in series to each
controller and accessory would it not?
>The ripple issue is no urban legend. It is very real and can
>be easily demonstrated. A battery charger is probably about the
>worse supply you can use with a slot car.
Probably.
>Wall-warts are not
>very far behind.
I'm not familiar with this term, presumably you mean those huge, ugly
lumps of plastic which plug into mains sockets and deliver low voltage
(DC usually) output.
I would add, the older style free-standing power supplies that were
provided by the likes of Scalextric work in the same way too so are
probably just as susceptible to this problem.
>Batteries provide a smooth output but may not
>provide the voltage you truly want and may be a little hazardous
>in the home.
Quite, not to mention weighing a ton.
>Don't discount the value of a nice, regulated
>power supply. One good one will last a lifetime.
Alternatively, my power supply is effectively two. Each car gets its own
transformer, rectifier and output so there is nowhere for the reverse
current to flow. (So long as I don't put any accessories on it.)
Interesting ...
--
Peter Zivanovic
Paul
John Ford
NEVER USE A BATTERY CHARGER TO RUN YOUR SLOT CARS.
Sorry for yelling,
Nothing will get you in trouble quicker than talking to a slot racing
electrical engineer. ;-)
John Ford
floyd
Just to get my two-cents worth in, I would point out that a
Group 27 motor, pulling out of a heavily glued turn, can pull 8,
that's right, EIGHT amps. That's a single car. I know the load
is momentary, but your power supply won't care how long it
lasts. The math has been done before, buy a couple car
batteries. You'll get smooth, clean, 100% DC power, applied
evenly across the whole track, and it won't cost a mint either.
For safety's sake, don't charge during the race, and be aware of
the other safety considerations involved in using lead-acid
batteries (hydrogen, first and foremost).
Allright, maybe you won't be running Gp 27s, but even
cobalt 12s will give a power supply a mean workout. Go with the
batteries. You can get battery cases at a boat place, cheap, to
keep the wiring under cover, and maintenance-free batteries
produce virtually no gases when charging. Good luck with your
track!
J. J. Smith
mdseay1...@juno.com.invalid says...
I have looked at Radio Shack power supplies for my 3-lane track, and for
the life of me I do not know which one to get. Knowing squat about
electricity and being new to the hobby doesn't help much either.
I'm not worrried about cost. I just want to plug it in when I get it to
the track. If I need a seperate power supply for each lane then so be it.
I would rather have more power than not enough.
J. J. Smith
says...
> I have looked at Radio Shack power supplies for my 3-lane track, and for
> the life of me I do not know which one to get. Knowing squat about
> electricity and being new to the hobby doesn't help much either.
>
> I'm not worrried about cost. I just want to plug it in when I get it to
> the track. If I need a seperate power supply for each lane then so be it.
> I would rather have more power than not enough.
Perhaps if someone has a second they could help me out. I would go to the
guy I bought the track form but he says that a car battery is good
enough. I don't like that advice.
Anyways, there is a surplus store here in town that sells power supplies.
http://fcsurplus.lweb.net/electric/pwrsplpg.htm
I am not affiliated with them in any way, shape or form. But if someone
could check out the power supplies they have listed there and hopefully
tell me which one will work with my 3-lane track. We are starting out
with group 10 cars, and will be moving up from there, so I would like
something that will be good for us for a long, long time. Once again,
cost is no object. Even if I need 1 per lane is fine with me.
Gregory Braun -- Software Design
Radio Shack makes a nice 9-15 Volt Variable DC Power Supply producing 15
Amperes for $99.00. This unit has Voltage and Amperage meters on the front
panel. RS 910-4379. A variable power supply will allow you to reduce the
voltage when young children or novices race.
Radio shack also has their 0-30 Volt Variable DC Power Supply producing 7
Amperes on sale for $99.97. This unit also has Voltage and Amperage meters.
This unit normally sells for $199.95 so the current sale price is a great
deal. RS 910-0454
You did not specify what scale you plan to use these with. 1:32 Scale cars
normally need 12-13.8 VDC making the RS 910-4379 ideal.
HO Scale cars require 18-22 VDC so the RS 910-0454 would work well here.
These power supplies can be ordered on-line at:
They're listed in the Catalog -> Test & Measurement -> Power Supplies
section.
You could purchase multiples of either Power Supply if you want to power
each lane individually.
See the [Power] section of my web site at:
http://www.gregorybraun.com/slotcars
for a review of the 0-30 VDC power supply (RS 910-0454)
Bak2Zero
CB/ham radio folks.
Shannon
George Warner
<z-c...@zzmail.demon.co.uk> wrote:
> In article <warnergt-C9BF93...@news.ptd.net>, George Warner
> <warn...@ptd.net> writes
>
> >Here's the deceiving part. Cheap power supplies (such as a battery
> >charger) generally only rectify (using diodes) the output voltage.
> >They provide no filtering (capacitors) or regulation (electronic
> >devices). With a single slot car, these diodes actually prevent
> >this reverse current which causes the undue motor heating.
> Right, with you so far. Just to clarify, the diodes prevent the reverse
> current flowing - so there is no undue motor heating.
Yes, I could have phrased it better. Reverse current causes
undue motor heating. The diodes prevent this.
> >However, when you put a second (or more) cars on the track,
> Just to clarify, do you mean when you are driving two or more cars from
> one DC-output?
Yes.
> >the
> >scenario changes. The additional car(s) actually create a load
> >which allows current to now flow backward through motors during
> >the low points of the power supply voltage. Now, you get the
> >excessive heating. The motor that was cool as a cucumber in warm-up
> >is now on the verge of frying during a race.
> Some slot car manufacturers offer electrical accessories that are
> powered by the same power supply as the car(s). Presumably these have
> the same effect as another car would?
Yes.
> The way to overcome this would be to fit a diode in series to each
> controller and accessory would it not?
That would work. Yes.
> >The ripple issue is no urban legend. It is very real and can
> >be easily demonstrated. A battery charger is probably about the
> >worse supply you can use with a slot car.
> Probably.
> >Wall-warts are not
> >very far behind.
> I'm not familiar with this term, presumably you mean those huge, ugly
> lumps of plastic which plug into mains sockets and deliver low voltage
> (DC usually) output.
Right again.
> I would add, the older style free-standing power supplies that were
> provided by the likes of Scalextric work in the same way too so are
> probably just as susceptible to this problem.
Yes.
> >Batteries provide a smooth output but may not
> >provide the voltage you truly want and may be a little hazardous
> >in the home.
> Quite, not to mention weighing a ton.
> >Don't discount the value of a nice, regulated
> >power supply. One good one will last a lifetime.
> Alternatively, my power supply is effectively two. Each car gets its own
> transformer, rectifier and output so there is nowhere for the reverse
> current to flow. (So long as I don't put any accessories on it.)
True but the shortcoming to this setup is that each car may not
bet getting the same voltage. A single supply ensures that
everyone gets the same voltage.
Peter Zivanovic
<warn...@ptd.net> writes
snip
>> >Don't discount the value of a nice, regulated
>> >power supply. One good one will last a lifetime.
>
>> Alternatively, my power supply is effectively two. Each car gets its own
>> transformer, rectifier and output so there is nowhere for the reverse
>> current to flow. (So long as I don't put any accessories on it.)
>
>True but the shortcoming to this setup is that each car may not
>bet getting the same voltage. A single supply ensures that
>everyone gets the same voltage.
Well, granted they may vary /slightly/ but if you use the same
components throughout (transformer, rectifier, safety cut-out - and
smoothing capacitor if used) this should be minimal. I would guess it
would be of less significance than variations in the controllers and
cars. Also, the power tends to be "fixed" to a lane and if you're
racing, you use each lane in turn so any slight differences should
affect everyone evenly over the session.
Nevertheless, thanks for the insight. It's been interesting.
--
Peter