Re-winding solenoids.

[Jeffrey Angus]

Just a few abstract thoughts here. It makes sense to me,
but then I've been known to over look the obvious on
occasion. ;-)

I have a solenoid coil that actuates a large 3-pole
contactor. A short pulse to pull up on a lever that
will toggle it from on position to another, and back.

Making measurements of the solenoid coil, although
potted in epoxy, yields a few measurements and a
couple of guesses.

<http://www.pronine.ca/multind.htm>

Coil form 1" diameter, 1-3/8" width and 1.5" depth.
Going backwards on a solenoid coil java script, yields
a matching 125 mH inductance (as measured) and 95 ohm
DCR (as measured) for 2500 turns of #30 AWG which will
fill the bobbin.

This a 480 VAC actuator.

Am I headed in the right direction if I assume the key
factor here is ampere turns?

Not allowing for the added inductance by a movable core,
this has an impedance of roughly 100 ohms. So that works
out to 4.8 amps or 12,000 ampere turns.

Substituting 2000 turns of #28 AWG yields 80 mH, and 42
Ohms. And subsequently roughly 12,000 ampere turns at
240 VAC.

Putting 240 VAC across the 480 VAC coil yields only 6,000
ampere turns and obviously is NOT enough to actuate the
contactor transfer mechanism.

The reason I'm curious is that ASCO seems to think that
the replacement coil for this is worth $585, although
they will sell it as the "sale price" of only $421.80.

Jeff-1.0
The other other one

--
"Everything from Crackers to Coffins"

[Jamie]

Beware that some coils are dual coils with diodes potted in them.

WHen a diode fails in one of these, they tend to generate some noise
when energized. This is because one coil is pushing both directions
against the other that isn't.

Basically what this means is, the coil is designed to operate in a
DC state.

What we have done in the past if we suspected a shorted diode in one
of these types is to put a bridge rectifier in front of it.

But I can tell you this, if the construction of core around this coil
in the device that is using it has a laminated type layers, chances are,
you have a simple coil and there is some form of shading device near the
contact point where the accouter makes contact with it.

What is this thing? A ratcheting three position device? being ASCO, it
sounds like some kind of valve.

Jamie

[Jeff Liebermann]

On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>This a 480 VAC actuator.

Make, model, and photograph?

Is there a copper D-ring on the top end of the solenoid?

If the coil it dead, try disolving the epoxy.
<http://www.esslinger.com/attack.aspx>
It will also make a useful coil form.

If you know the core dimensions and the wire guage, you can estimate
the number of turns.

>The reason I'm curious is that ASCO seems to think that
>the replacement coil for this is worth $585, although
>they will sell it as the "sale price" of only $421.80.

Check eBay?


--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[Jeffrey Angus]

On 10/16/2011 4:33 PM, Jamie wrote:
> Beware that some coils are dual coils with diodes potted in them.
>
> WHen a diode fails in one of these, they tend to generate some noise
> when energized. This is because one coil is pushing both directions
> against the other that isn't.
>
> Basically what this means is, the coil is designed to operate in a
> DC state.
>
> What we have done in the past if we suspected a shorted diode in one
> of these types is to put a bridge rectifier in front of it.
>
> But I can tell you this, if the construction of core around this coil
> in the device that is using it has a laminated type layers, chances are,
> you have a simple coil and there is some form of shading device near the
> contact point where the accouter makes contact with it.
>
> What is this thing? A ratcheting three position device? being ASCO, it
> sounds like some kind of valve.

This is a simple multi-layer solenoid.
It is fed with 480 VAC via an external bridge rectifier.

It is a pull up actuated 100 amp 3-pole contactor.

It is physically identical to this one, with the excption of
being 3-poles rather than 2.

<http://www.ebay.com/itm/130520617745>

The solenoid is at the top left of the contactor with the bridge
rectifier on the side.

Jeff-1.0

[Jeffrey Angus]

On 10/16/2011 5:14 PM, Jeff Liebermann wrote:
> On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus<grend...@aim.com>
> wrote:
>
>> This a 480 VAC actuator.
>
> Make, model, and photograph?

A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC.
<http://www.ebay.com/itm/130520617745>

This is the coil itself from ASCO.
<http://www.ascoparts.com/343500-063.html>

> Is there a copper D-ring on the top end of the solenoid?

Nope.

> If the coil it dead, try disolving the epoxy.
> <http://www.esslinger.com/attack.aspx>
> It will also make a useful coil form.

Coil works perfectly with 480 VAC applied to the bridge
recitfier. My task is to wind a new coil that will work
at 240 VAC.

> If you know the core dimensions and the wire gauge, you

> can estimate the number of turns.

I did that, see the initial posting. Using DC resistance,
physical size and measured inductance.

>> The reason I'm curious is that ASCO seems to think that
>> the replacement coil for this is worth $585, although
>> they will sell it as the "sale price" of only $421.80.
>
> Check eBay?

They have the contactors available from $750 and up, and
complete units for $1500 and up.

No solenoids only.

Jeff-1.0

[spamtrap1888]

do you see the part number on this list? Seems considerably cheaper:

http://www.valvestore.com/products.asp?dept=1448

[Jamie]

Why don't you use a simple step up transformer for the coil?
you won't need a large one.

JAmie

[Jamie]

To add to that, a 1:1 control transformer of a very small size can
be wired as a buck boost to operate that coil.

Jamie

[Michael A. Terrell]

Tell him something he DOESN'T already know.


--
You can't have a sense of humor, if you have no sense.

[Jeffrey Angus]

On 10/16/2011 8:05 PM, Jamie wrote:
> Why don't you use a simple step up transformer for the coil?
> you won't need a large one.

Um, however briefly, the transformer needs to supply
5.2 amps at 480 volts to successfully energize the coil.

That's 2500 VA Even a 500 VA control transformer that I have
sags too much to properly actuate the transfer switch.

[Jeffrey Angus]

On 10/16/2011 8:12 PM, Jamie wrote:
> To add to that, a 1:1 control transformer of a very small size
> can be wired as a buck boost to operate that coil.

As I mentioned previously, the solenoid requires a 5.2 amp pulse
to properly actuate the contactor mechanism.

With a 240/240 control transformer wired up in boost mode that
would need at 1000 VA transformer as a bare minimum.

[Jamie]

Jeffrey Angus wrote:

> On 10/16/2011 8:05 PM, Jamie wrote:
>
>> Why don't you use a simple step up transformer for the coil?
>> you won't need a large one.
>
>
> Um, however briefly, the transformer needs to supply
> 5.2 amps at 480 volts to successfully energize the coil.
>
> That's 2500 VA Even a 500 VA control transformer that I have
> sags too much to properly actuate the transfer switch.
>
> Jeff-1.0
>

I find it hard to believe that coil is using that much? Are you
sure it's in proper working order? We have 500 amp contactors with
120V coils that only require about 2 amps to pull in. Something just
does not sound right, but what ever.



Jamie

[Jeffrey Angus]

On 10/16/2011 8:01 PM, Michael A. Terrell wrote:
> Tell him something he DOESN'T already know.

Heh, thanks Michael. What I don't know and would like to
know is if my thinking with regards to ampere turns is
correct. Because I CAN wind a new solenoid coil with a
1/2 pound spool of wire for about $20.

[Jamie]

Then it must be pushing a large load a long distance.

at that current, you looks like you have ~ 100 ohm coil.

which means the wire in the coil is rather a large gauge since
this is DC going to it.

I would start around 20awg and see what the DCR 1M is on the
chart. Then see if that will physically fit on the form.


Jamie.

[Jeffrey Angus]

On 10/16/2011 8:34 PM, Jamie wrote:
> I find it hard to believe that coil is using that much? Are
> you sure it's in proper working order? We have 500 amp
> contactors with 120V coils that only require about 2 amps
> to pull in. Something just does not sound right, but what
> ever.

Yes I am sure. And yes I know what some contactors take to
actuate the coils in a steady state holding condition.

To repeat. This is a pulsed operation. The auxiliary contacts
on the transfer switch contactor interrupt the source from the
solenoid as it actuates.

The solenoid core pulls up on a link that rotates the armature
of the contactor assembly from normal to emergency position.
Each time it is pulsed, it rotates it one way, then the other
way.

The actual amount of time (I haven't measured it) this takes
is under a second roughly.

[William Sommerwerck]

>> Tell him something he DOESN'T already know.

> Heh, thanks Michael. What I don't know and would like
> to know is if my thinking with regards to ampere turns is
> correct. Because I CAN wind a new solenoid coil with
> a 1/2 pound spool of wire for about $20.

Do you have good reason to believe that AWG 30 is the proper gauge, and that
your calculations are correct? If so, then buy the wire and do it. If it
doesn't work, you're out only $20 and the time it took to wind the coil.

I don't know enough about solenoids to properly judge your calculations. But
I don't see anything obviously wrong.

[Jeffrey Angus]

On 10/16/2011 8:44 PM, Jamie wrote:
> Then it must be pushing a large load a long distance.
>
> at that current, you looks like you have ~ 100 ohm coil

Did you read the details from my original posting? (Se below)

> which means the wire in the coil is rather a large gauge since
> this is DC going to it.
>
> I would start around 20awg and see what the DCR 1M is on the
> chart. Then see if that will physically fit on the form.

I originally wrote:
> Coil form 1" diameter, 1-3/8" width and 1.5" depth.
> Going backwards on a solenoid coil java script, yields
> a matching 125 mH inductance (as measured) and 95 ohm
> DCR (as measured) for 2500 turns of #30 AWG which will
> fill the bobbin.
>

> This a 480 VAC actuator.

roughly 100 ohms, yes.

This is NOT a constant pull and hold solenoid. This is a
pulsed operation.

> So that works out to 4.8 amps or 12,000 ampere turns.
>
> Substituting 2000 turns of #28 AWG yields 80 mH, and 42
> Ohms. And subsequently roughly 12,000 ampere turns at
> 240 VAC.

Based on: Ampere turns =
(Applied voltage * number of turns)/(coil resistance)

Both estimations of the needed number of turns and wire size
seem correct.

> Putting 240 VAC across the 480 VAC coil yields only 6,000
> ampere turns and obviously is NOT enough to actuate the
> contactor transfer mechanism.

This tends to indicate that ampere turns is indeed the magic
number as 6000 is not enough to actuate a mechanism that
appears to require 12,000.

[Jeffrey Angus]

On 10/16/2011 8:42 PM, William Sommerwerck wrote:
> Do you have good reason to believe that AWG 30 is the proper
> gauge, and that your calculations are correct?

<http://www.pronine.ca/multind.htm>

Yields both the correct inductance and DC resistance with #30
AWG for the assumptions I've made for the physical size of the
coil bobbin.

> If so, then buy the wire and do it. If it doesn't work, you're
> out only $20 and the time it took to wind the coil.
>
> I don't know enough about solenoids to properly judge your
> calculations. But I don't see anything obviously wrong.

And that's why I thought I'd ask here. I was hoping to find
someone that _is_ familiar enough to at least tell me, "Yeah,
you seem to be heading in the right direction."

[spamtrap1888]

You didn't say this solenoid was part of a transfer switch. This
raises the stakes substantially. Transfer switches are used to switch
the mains supply to a generator when mains power is interrupted. They
serve two main purposes: to keep critical equipment functioning when
mains power is interrupted, and to deenergize the power line so that
workers can assume it is deenergized when they work on it.

Now, the transfer switch was tested to meet specifications with the
designed solenoid installed. Knowing nothing of the design or
construction of the component, you propose to roll your own and stick
it in.

Which would be fine, if no one's life depended on its working. And if
the vendor would stand behind your handicraft.

I don't think Asco could reasonably foresee that someone would use a
program that gives the number of turns for an air-core inductor to
design a part for a life-safety application.

[Jeff Liebermann]

On Sun, 16 Oct 2011 17:30:05 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>Coil works perfectly with 480 VAC applied to the bridge
>recitfier. My task is to wind a new coil that will work
>at 240 VAC.

You left that out of your initial rant. First sentence should be what
the [deleted expletive] you're trying to accomplish.

>I did that, see the initial posting. Using DC resistance,
>physical size and measured inductance.

What you want is an equal amount of magnetic force (i.e. gilberts) or
ampere-turns for both the 480VAC and 240VAC coils.

480VAC coil = 125mH and 95 ohms
XL = 2*Pi*60*125*10^-3 = 47 ohm
Total impedance is the vector sum of 95 ohms and 47 ohms =
Z = sqrt(95^2 + 47^2) = 105 ohms
Current is:
I = 480VAC / 105 ohms = 4.5A
2500 turns * 4.5A = 11,250 AT
Ok, you got that part correct.

Trying a different gauge for 240VAC. The hard part will be keeping
the max diameter to under 1.5" OD.

<http://www.pronine.ca/multind.htm>
For #29awg, 75mH, 1990 turns, 51 ohms resistance.
XL = 2*Pi*60*75*10^-3 = 28 ohm
Z = sqrt(51^2 + 28^2) = 63 ohms
I = 240VAC / 63 ohms = 3.8A
1990 turns * 3.8A = 7580 AT

For #28awg, 60mH, 1759 turns, 37 ohms resistance.
XL = 2*Pi*60*60*10^-3 = 22.5 ohm
Z = sqrt(51^2 + 37^2) = 63 ohms
I = 240VAC / 63 ohms = 3.8A
1759 turns * 3.8A = 6700 AT

Ok, that's not going to work. Most of the impedance is coming from
the DC resistance of the wire. Decreasing the gauge decreases this
resistance, but also decreases the number of turns that will fit on a
the spool to a maximum OD of 1.5". This isn't working. I give up for
tonite.

[Jeffrey Angus]

On 10/16/2011 11:08 PM, spamtrap1888 wrote:
> You didn't say this solenoid was part of a transfer switch. This
> raises the stakes substantially. Transfer switches are used to switch
> the mains supply to a generator when mains power is interrupted. They
> serve two main purposes: to keep critical equipment functioning when
> mains power is interrupted, and to deenergize the power line so that
> workers can assume it is deenergized when they work on it.
>
> Now, the transfer switch was tested to meet specifications with the
> designed solenoid installed. Knowing nothing of the design or
> construction of the component, you propose to roll your own and stick
> it in.
>
> Which would be fine, if no one's life depended on its working. And if
> the vendor would stand behind your handicraft.
>
> I don't think Asco could reasonably foresee that someone would use a
> program that gives the number of turns for an air-core inductor to
> design a part for a life-safety application.

Thank you for your information.

It changes nothing. The original solenoid develops about 12,000
ampere turns at 480 Volts. The replacement needs to develop 12,000
ampere turns at 240 volts.

If this were a customer, such as a extended care center where I
originally bought the used generator from and replaced their
original automatic transfer switch with a new compatible one I
would have (and did) take proper steps to insure everything worked
within the confines of a life-safety application.

This is a manual transfer switch with some control logic to determine
if all the power is present prior to switching. What in essence it
does is not allowing you to switch to a non-existent source.

I asked for an opinion that ampere turns was the right direction I
was headed in to change an operating solenoid from 480 to 240 volts.

I did not ask form someone such as yourself to presume that I totally
lack the ethics to endanger life with a crap modification.

Ya know, the way this transfer switch operates, I can just as easily
add the optional "manual handle" on the side of the box to switch from
normal to emergency power and throw away all the complicated stuff
inside.

As far as life safety is concerned, this is to handle a loss of power
at the shop I operate. Simple. "The power failed." Go outside, start
the generator and once it's running go back and flip the transfer
switch. When the utility power returns and stays on, flip the siwtch
aback and then go outside and turn the generator off.

This really isn't rocket science.

[Jeffrey Angus]

On 10/16/2011 11:11 PM, Jeff Liebermann wrote:
> Ok, that's not going to work. Most of the impedance is coming from
> the DC resistance of the wire. Decreasing the gauge decreases this
> resistance, but also decreases the number of turns that will fit on a
> the spool to a maximum OD of 1.5". This isn't working. I give up for
> tonite.

Well as long as your bitching at me for leaving something out....

The original coil is being fed through a bridge rectifier (mentioned
elsewhere in the thread). So the AC impedance is less of an issue.

Using the proline scripting, I came up with 80 mH using #28 AWG wire,
1988 turns and 1.54" outside diameter with 42.63 ohms.

I come up with 11192 ampere turns. I've got some wiggle room to
increase the bobbin size a bit. So rest well good sir, we are at
a point that is "close enough" to wind up a prototype and see if
works properly.

If it does, then it gets potted in Epoxy to match the original
physical dimensions and we call it a success.

[Jeff Liebermann]

On Mon, 17 Oct 2011 02:51:21 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>On 10/16/2011 11:11 PM, Jeff Liebermann wrote:
>> Ok, that's not going to work. Most of the impedance is coming from
>> the DC resistance of the wire. Decreasing the gauge decreases this
>> resistance, but also decreases the number of turns that will fit on a
>> the spool to a maximum OD of 1.5". This isn't working. I give up for
>> tonite.
>
>Well as long as your bitching at me for leaving something out....

I always find something to complain about. It's part of my standard
usenet protocol. Nothing personal.

>The original coil is being fed through a bridge rectifier (mentioned
>elsewhere in the thread). So the AC impedance is less of an issue.

Bad news. 60Hz is still AC. The AC current, is determined by the AC
impedance also known as Z. Fortunately, most of it comes from the
resistance of the wires, making the coil specs easier to guess.

>Using the proline scripting, I came up with 80 mH using #28 AWG wire,
>1988 turns and 1.54" outside diameter with 42.63 ohms.

You cheated by going over the OD by 0.04". Assuming you can pack the
windings in as tight as the original, that shouldn't be a problem. I'm
not all that confident you can do it. Use a mandrel and a slow
turning lathe.

>I come up with 11192 ampere turns. I've got some wiggle room to
>increase the bobbin size a bit. So rest well good sir, we are at
>a point that is "close enough" to wind up a prototype and see if
>works properly.

It will probably work. I just hate to say that as I'm sure you'll
blame me when it explodes and sprays coil bobbin parts all over the
shop. It might help to immolate an old solenoid on the barbeque as a
burnt offering to the god of electric power for a favorable outcome.

>If it does, then it gets potted in Epoxy to match the original
>physical dimensions and we call it a success.

Right. Hide the evidence. Be sure to embalm the windings in yellow
Kapton (Polyimide) high temp tape before potting. I learned that the
hard way after trying to pot some radios. The epoxy shrinks as it
hardens, which likes to tear wires away from their attachment points.
The tape provides an easy air space for the epoxy to shrink.

[Jeffrey Angus]

On 10/17/2011 10:37 AM, Jeff Liebermann wrote:
> I always find something to complain about. It's part of my standard
> usenet protocol. Nothing personal.

Well of course, I've known you long enough now to fully understand
the protocol. ;-)

> You cheated by going over the OD by 0.04". Assuming you can pack the
> windings in as tight as the original, that shouldn't be a problem. I'm
> not all that confident you can do it. Use a mandrel and a slow
> turning lathe.

The physical demisions after the epoxy potting are 1.55, instead of
my guess of 1.375), and 1.66 rather than my also guess of of 1.50.

> It will probably work. I just hate to say that as I'm sure you'll
> blame me when it explodes and sprays coil bobbin parts all over the
> shop.

Isn't that also standard Usenet protocol?

> Right. Hide the evidence. Be sure to embalm the windings in yellow
> Kapton (Polyimide) high temp tape before potting.

I still have several rolls here at the shop from when I'd rewind
surplus wall warts for laughs.

Jeff-1.0
the other other one.

Having a vacuum pot and temperature chamber helps make stuff
"right" when you do it. I kind of prefer a polyurethane for
potting myself.

[Jeff Liebermann]

On Mon, 17 Oct 2011 11:02:42 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>Isn't that also standard Usenet protocol?

Yes. The first step to analyzing a failure is to blame someone.

>Having a vacuum pot and temperature chamber helps make stuff
>"right" when you do it. I kind of prefer a polyurethane for
>potting myself.

I like to use Bondo, because it doesn't shrink.

Way back in the days when I still received a regular paycheck, the
company had a "modular products" division that sold data converters
into such non-critical applications like missiles and air traffic
control systems. Instead of just dumping the electronics into a
potting shell and filling it with epoxy, they would first fill it
almost to the pour hole with sand and then top it off with epoxy. The
thermal conductivity of epoxy is slightly better than lousy. The sand
gives an even temperature distribution, protects against mechanical
shock, and is cheaper than epoxy. It also makes post-potting repair
somewhat possible. Filling the bobbin with sand before potting isn't
going to do anything useful for your solenoid, but I thought I would
mention it for future applications.

[Dave M]

You said in an earlier post that the current in the coil needs to be around
5 amps, and you propose to use 28 AWG wire to wind it.
AWG 28 wire has a rated ampacity for chassis wiring (inside a bundle,
similar to your solenoid coil), is only 1.4 amps. I doubt that your coil
would last very long with that amount of current.
More investigation is necessary. Might be less painful to spring for the
proper solenoid from the manufacturer.
--
David
dgminala at mediacombb dot net

[Dave M]

OOps.. I got that wrong.. That figure was the capacity in free air... The
capacity of AWG28 wire in an enclosed space is 0.83 amps.

[Jeffrey Angus]

On 10/17/2011 2:21 PM, Dave M wrote:
> You said in an earlier post that the current in the coil needs to be
> around 5 amps, and you propose to use 28 AWG wire to wind it.
> AWG 28 wire has a rated ampacity for chassis wiring (inside a bundle,
> similar to your solenoid coil), is only 1.4 amps. I doubt that your
> coil would last very long with that amount of current.
> More investigation is necessary. Might be less painful to spring for
> the proper solenoid from the manufacturer.
>
> OOps.. I got that wrong.. That figure was the capacity in free air... The
> capacity of AWG28 wire in an enclosed space is 0.83 amps.

I'm sure that it is. The original coil at 480 volts draws 5.2 amps
and is wounnd with #30 AWG.

Guess I need to repeat this. It is PULSED not STEADY operation.

[Jamie]

You know, at this point, you pretty much don't care I would assume how
ever, have you thought about constructing a voltage double rectifier
instead of that bridge rectifier to drive that coil?





+-------+-------++
| | |
+ | |
D1 - | |
^ | |
| | +
C1 + + C|
240 AC in | --- C| 480 Solenoid
|| | ---C2 C|
+---+-||+------+ + |
|| + | +
| | |
- | |
D2 ^ | |
240 AC in + | |
| + |
+-------------+-------++-------+
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


I suppose if you had to motor caps around you could use those, the
large ones of course.

What ever.
Jamie

[Jeff Liebermann]

Good idea. The caps will need to be charged by the 240VAC line
voltage in a few cycles in order to get any kind of usable response
time for pulsed operation. That means the caps are going to be rather
big. A rough guess would be:

AC impedance of the coil is roughly:
480VAC / 5A = 96 ohms
To get C2 up to about 90% of full charge in 2 cycles, the capacitive
reactance of C1 would need to be about:
Xc = 96 * 0.1 = 9.6 ohms
At 60Hz, that's 276 uF. 330uf 600VDC caps should work. I'm not very
confident with my crude approximations. Therefore, I would feed the
model to LTSpice and see what it's really going to do.

[Jeffrey Angus]

On 10/18/2011 11:47 AM, Jeff Liebermann wrote:
> At 60Hz, that's 276 uF. 330uf 600VDC caps should work. I'm not very
> confident with my crude approximations. Therefore, I would feed the
> model to LTSpice and see what it's really going to do.

You're charging to the peak values, not RMS, so it's going to be 680
volts at a minimum, and probably more like 750 for some margin of
safety.

Caps of that size and rating will end up costing as much as the coil
itself.

Jeff

[Jeffrey Angus]

On 10/17/2011 6:05 PM, Jamie wrote:
>>
> You know, at this point, you pretty much don't care

You're right. I don't. Because my original question was
in regards to ampere turns and rewinding a solenoid for
a different operating voltage.

Because so far, with one notable exception, everyone has
insisted on coming up with some Rube Goldberg solution or
accusing me of trying to murder widows and orphans.

[spamtrap1888]

On Oct 19, 5:09 am, Jeffrey Angus <grendel...@aim.com> wrote:
> On 10/17/2011 6:05 PM, Jamie wrote:
>
>
>
> > You know, at this point, you pretty much don't care
>
> You're right. I don't. Because my original question was
> in regards to ampere turns and rewinding a solenoid for
> a different operating voltage.

I wish that that had been your original question, which was a rambling
stream of consciousness. Your reference to a program for calculating
aircore inductors made me think you were using "solenoid" in the sense
of "helical coil."

>
> Because so far, with one notable exception, everyone has
> insisted on coming up with some Rube Goldberg solution or
> accusing me of trying to murder widows and orphans.
>

Your desire to save $380 in the belief that ASCO was screwing its
customers with jacked-up prices seemed a bit unreasonable, the more so
when you revealed the true application for the solenoid actuator.

But your juryrig would merely produce widows and orphans, not kill
them. Only the lineman trying to restore power would be killed if your
Rube Goldberg solution failed to work.

[Michael A. Terrell]

spamtrap1888 wrote:
>
> Your desire to save $380 in the belief that ASCO was screwing its
> customers with jacked-up prices seemed a bit unreasonable, the more so
> when you revealed the true application for the solenoid actuator.
>
> But your juryrig would merely produce widows and orphans, not kill
> them. Only the lineman trying to restore power would be killed if your
> Rube Goldberg solution failed to work.

Can't follow a thread, can you? It's for his workshop.

[Jeffrey Angus]

On 10/19/2011 10:52 AM, spamtrap1888 wrote:
> But your juryrig would merely produce widows and orphans, not kill
> them. Only the lineman trying to restore power would be killed if your
> Rube Goldberg solution failed to work.

Since you seem to be so good at divination....Pray tell me just
exactly how a three-pole double throw transfer switch can connect
the emergency power to the line rather than the load.

The ONLY thing this switch can do if the solenoid fails is to NOT
actuate the switch from one position the other.

But I'm sure you have a reasonable explanation on how that can
not be the case here.

[Jamie]

I must say, you are an idiot!

How is the device itself any less dangerous than using an alternate to
operate it?

Jamie

[spamtrap1888]

On Oct 19, 3:14 pm, Jamie

If the alternate does not operate sufficiently like the original.

If he could explain how the actuator works and what the important
parameters were, we could speculate as to all the possible failure
modes.

[spamtrap1888]

I see that only the ASCO 4000 and 7000 series are closed-transition
switches, i.e. break before make, not the Series 940 -- which I had to
look up from the replacement part number you gave.

My bad, I suppose.

[Jamie]

You can speculate all you want. You sound like an attorney looking for
work or closely related to one.

If you read the blog, you would see what he is using if for, and if
he really wants you to know, I am sure he'll refresh your memory.

Jamie

[Jeffrey Angus]

On 10/19/2011 8:39 PM, spamtrap1888 wrote:
> I see that only the ASCO 4000 and 7000 series are closed-transition
> switches, i.e. break before make, not the Series 940 -- which I had to
> look up from the replacement part number you gave.
>
> My bad, I suppose.

I suppose. The solenoid coil listed is for the series 940. It
is also used for several other series. Specifically, in my case,
the Series 386 manual transfer switch.

And in case you missed it earlier, here is the link for an eBay
auction showing picturs of the transfer switch contactor.

A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC.
<http://www.ebay.com/itm/130520617745>

And if you go to the partsasco.com website and look up the replacement
part numbers for the model 300 or 386, it directs you to the coil
marked as being for the series 940.

This is the coil itself from ASCO.
<http://www.ascoparts.com/343500-063.html>

But again, you're making all sorts of asumption looking to find
fault. You've done nothing what so ever to answer the question
on rewinding a solenoid to operate at 240 volts rather than 480.

[spamtrap1888]

On Oct 19, 6:59 pm, Jamie

I used to break things for a living. Before that, I had to worry about
the adequacy of insulation. From his first post, the guy did not
appear to understand much of anything. I hoped he at least would not
kill anyone.

[Jeffrey Angus]

On 10/19/2011 9:38 PM, spamtrap1888 wrote:
> From his first post, the guy did not appear to understand
> much of anything. I hoped he at least would not kill anyone.

Really? Explain how you came to that conclusion.

I started with known measured numbers. Worked backwards with
a calculator to get the unknown. From there I went forward
towards what I thought was correct.

Then asked if what I was doing sounded right. I.e. basing the
requirements on ampere turns.

I even went so far as to include the calculator I used to
determine the number turns based on the physical size, DC
resistance and measured inductance.

So, and unfortunately VERY typical of Usenet, I've had to put
up with unfounded personal attacks and a whole plethora of
"How you should do anything except what you want to."

[George Herold]

On Oct 16, 4:48 pm, Jeffrey Angus <grendel...@aim.com> wrote:
> Just a few abstract thoughts here. It makes sense to me,
> but then I've been known to over look the obvious on
> occasion. ;-)
>
> I have a solenoid coil that actuates a large 3-pole
> contactor. A short pulse to pull up on a lever that
> will toggle it from on position to another, and back.
>
> Making measurements of the solenoid coil, although
> potted in epoxy, yields a few measurements and a
> couple of guesses.
>
> <http://www.pronine.ca/multind.htm>
>
> Coil form 1" diameter, 1-3/8" width and 1.5" depth.
> Going backwards on a solenoid coil java script, yields
> a matching 125 mH inductance (as measured) and 95 ohm
> DCR (as measured) for 2500 turns of #30 AWG which will
> fill the bobbin.
>
> This a 480 VAC actuator.
>
> Am I headed in the right direction if I assume the key
> factor here is ampere turns?
>
> Not allowing for the added inductance by a movable core,
> this has an impedance of roughly 100 ohms. So that works
> out to 4.8 amps or 12,000 ampere turns.
>
> Substituting 2000 turns of #28 AWG yields 80 mH, and 42
> Ohms. And subsequently roughly 12,000 ampere turns at
> 240 VAC.
>
> Putting 240 VAC across the 480 VAC coil yields only 6,000
> ampere turns and obviously is NOT enough to actuate the
> contactor transfer mechanism.
>
> The reason I'm curious is that ASCO seems to think that
> the replacement coil for this is worth $585, although
> they will sell it as the "sale price" of only $421.80.
>
> Jeff-1.0
> The other other one

>
> --
> "Everything from Crackers to Coffins"

Hi Jeff, I know nothing about power stuff or soleniod coils. I have
made a few open air magnetics. (Usually Helmholtz things) If the size
of both air coils is the same, then I believe your calculations are
correct. It's only the magnetic field strength that you need to match
and that's proportional to number of amp-turns. Wind away I say!

George H.

[George Herold]

Driving home, I was thinking that since you're doing a pulsed thing
you may care about the L/R time constant. (Is the pulse time much
longer than that?) Did 'your' program spit out inductance values
too? (Forgive me, I'm too lazy to look for them.) For 'thin' coils
you'd expect the inducatance (for the low voltage coil) to go down by
four and the resistance to go down by two, so a decrease of two in the
time constant... hardly seems like it would matter, unless somethng
else in the circuit is expectng it to take longer. For your fat coil
the change in time constant is likely even less.

George H.


>
> George H.- Hide quoted text -
>
> - Show quoted text -

Oh

[Jeffrey Angus]

On 10/20/2011 5:54 PM, George Herold wrote:
> Driving home, I was thinking that since you're doing a pulsed thing
> you may care about the L/R time constant. (Is the pulse time much
> longer than that?)

The pulse is mechanically derived.
The small control relay energizes the solenoid. When the solenoid
causes the transfer switch to actuate, the auxiliary contacts
open the solenoid connection.

Jeff-1.0

[josephkk]

On Wed, 19 Oct 2011 21:32:14 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

Just for grins, Jeff 1.0 have you tried spice models of the rectifier
solenoid at 480 and 240? It may help you see something you may have
missed. BTW i expect you will replace the bridge with one appropriated
rated for the solenoid?

?-)

[Jeffrey Angus]

On 10/20/2011 9:51 PM, josephkk wrote:
> Just for grins, Jeff 1.0 have you tried spice models of the rectifier
> solenoid at 480 and 240? It may help you see something you may have
> missed.

It hadn't occurred to me to do that. It's pretty much of a static
operation. You apply power, it pulls up on the armature. When the
mechanism changes position, an auxiliary switch disconnects the
solenoid.

> BTW i expect you will replace the bridge with one appropriated
> rated for the solenoid?

The original bridge was dealing with 480 vac @ 5.2 amps. The new
coil will present a load of about 4 amps @ 240 vac. It's not an
issue.

[Jeff Liebermann]

On Fri, 21 Oct 2011 05:22:39 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>On 10/20/2011 9:51 PM, josephkk wrote:
>> Just for grins, Jeff 1.0 have you tried spice models of the rectifier
>> solenoid at 480 and 240? It may help you see something you may have
>> missed.
>
>It hadn't occurred to me to do that.

See <jm9r97l1ngmq2e456...@4ax.com>
where I mumbled:

At 60Hz, that's 276 uF. 330uf 600VDC caps should work.
I'm not very confident with my crude approximations. Therefore,
I would feed the model to LTSpice and see what it's really going
to do.

<http://www.linear.com/designtools/software/#LTspice>
Look for current and voltage spikes.

>It's pretty much of a static
>operation. You apply power, it pulls up on the armature. When the
>mechanism changes position, an auxiliary switch disconnects the
>solenoid.

You can specify an input pulse with:

Syntax: Ixxx n+ n- PULSE(Ioff Ion Tdelay Trise Tfall Ton Tperiod
Ncycles)

There are also other circuit simulators that might work:
<http://www.falstad.com/circuit/> (Java)

Make me rich and I'll do the recti-fire and sol-e-void model for you.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS

[josephkk]

On Fri, 21 Oct 2011 05:22:39 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

>On 10/20/2011 9:51 PM, josephkk wrote:
>> Just for grins, Jeff 1.0 have you tried spice models of the rectifier
>> solenoid at 480 and 240? It may help you see something you may have
>> missed.
>
>It hadn't occurred to me to do that. It's pretty much of a static
>operation. You apply power, it pulls up on the armature. When the
>mechanism changes position, an auxiliary switch disconnects the
>solenoid.

I expect you can learn interesting things looking at the current waveforms
in the various configurations.

>
>> BTW i expect you will replace the bridge with one appropriated
>> rated for the solenoid?
>
>The original bridge was dealing with 480 vac @ 5.2 amps. The new
>coil will present a load of about 4 amps @ 240 vac. It's not an
>issue.

That does not make sense for the ampere-turns argument. The number of
turns drops dramatically thus the current must increase accordingly.

>
>Jeff-1.0

[Jeffrey Angus]

On 10/22/2011 11:55 PM, josephkk wrote:
>> >
>> >The original bridge was dealing with 480 vac @ 5.2 amps. The new
>> >coil will present a load of about 4 amps @ 240 vac. It's not an
>> >issue.
> That does not make sense for the ampere-turns argument. The number of
> turns drops dramatically thus the current must increase accordingly.
>

480v coil 2500 turns @ 4.8 amps
240 coil 2000 turns @ 6.0 amps

[josephkk]

On Sun, 23 Oct 2011 03:36:07 -0500, Jeffrey Angus <grend...@aim.com>
wrote:

Not as bad of a turns drop as thought. The new numbers make sense.

?-)

[Jeffrey Angus]

A follow up to this exercise.

Using 1/16" PVC for the ends and schedule 40 1/2" PVC
for the core, I wound 2000 turns of #28 wire on the
form and put things together to test them.

It works with 240 VAC across the bridge rectifier now.

And yes, the coil heats up. It's trying to dissipate
1440 watts. (240 VAC @ 6 amps)

The contacts on the transfer switch disconnect the
solenoid coil from power as soon as it starts to move.
Inertia carries it through the sequence.

Jeff-1.0

[Jeff Liebermann]

On Sun, 13 Nov 2011 15:08:29 -0600, Jeffrey Angus <grend...@aim.com>
wrote:

>And yes, the coil heats up. It's trying to dissipate
>1440 watts. (240 VAC @ 6 amps)

You might want to add a thermal fuse in series with the coil. It the
contactor gets stuck in the energized position, you might have a fire.

>The contacts on the transfer switch disconnect the
>solenoid coil from power as soon as it starts to move.
>Inertia carries it through the sequence.

That happens it the actuator gets stuck or if the energizing voltage
is unusually low? Duz it stick in the "on" state?

Worrying about the widows and orphans this might harm...

[Jeffrey Angus]

On 11/13/2011 6:19 PM, Jeff Liebermann wrote:
> On Sun, 13 Nov 2011 15:08:29 -0600, Jeffrey Angus<grend...@aim.com>
> wrote:
>
>> >And yes, the coil heats up. It's trying to dissipate
>> >1440 watts. (240 VAC @ 6 amps)
> You might want to add a thermal fuse in series with the coil. It the
> contactor gets stuck in the energized position, you might have a fire.

There is that. See below...

>> >The contacts on the transfer switch disconnect the
>> >solenoid coil from power as soon as it starts to move.
>> >Inertia carries it through the sequence.
> That happens it the actuator gets stuck or if the energizing voltage
> is unusually low? Duz it stick in the "on" state?
>
> Worrying about the widows and orphans this might harm...

See, now this is where everyone got upset over nothing.

This whole exercise was to see _IF_ I could correctly wind a
replacement solenoid for 240 V rather than the original 480 V.

Now that I've satisfied my curiosity, I'm going to sell it in
it's original format (480 v 3-phase) as THAT is where it's value
lies.

Jeff

[Jeff Liebermann]

On Sun, 13 Nov 2011 20:47:45 -0600, Jeffrey Angus <grend...@aim.com>
wrote:

>This whole exercise was to see _IF_ I could correctly wind a
>replacement solenoid for 240 V rather than the original 480 V.
>
>Now that I've satisfied my curiosity, I'm going to sell it in
>it's original format (480 v 3-phase) as THAT is where it's value
>lies.

So, this was all an academic exercise, with no practical purpose or
monetary value? Had I known, I would have been less helpful and more
insulting. You should feel guilty for having wasted my time. For
penitence, please either flog yourself, or send me an appropriate
percentage of the proceeds.

[Jeffrey Angus]

On 11/13/2011 10:43 PM, Jeff Liebermann wrote:
> send me an appropriate percentage of the proceeds.

Fear not fearless leader, I'll remember to cut you in.

Jeff-1.0