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]

Jeffrey Angus 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

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 <grendelair@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 jeffl@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



--
"Everything from Crackers to Coffins"

 

[Jeffrey Angus]

On 10/16/2011 5:14 PM, Jeff Liebermann wrote:

On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus<grendelair@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



--
"Everything from Crackers to Coffins"

 

[spamtrap1888]

On Oct 16, 1:48 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.

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

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

 

[Michael A. Terrell]

Jamie wrote:

Jamie wrote:

Jeffrey Angus wrote:

On 10/16/2011 5:14 PM, Jeff Liebermann wrote:

On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus<grendelair@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



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

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.

Tell him something he DOESN'T already know.


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

 

[Jamie]

Jeffrey Angus wrote:

On 10/16/2011 5:14 PM, Jeff Liebermann wrote:

On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus<grendelair@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



Why don't you use a simple step up transformer for the coil?

you won't need a large one.

JAmie

 

[Jamie]

Jamie wrote:

Jeffrey Angus wrote:

On 10/16/2011 5:14 PM, Jeff Liebermann wrote:

On Sun, 16 Oct 2011 15:48:07 -0500, Jeffrey Angus<grendelair@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



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

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

 

[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.

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[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.

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[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.

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[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 8:34 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.

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[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.

 

[Jamie]

Jeffrey Angus wrote:

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.

Jeff-1.0

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 8:44 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.

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[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."

Jeff-1.0

--
"Everything from Crackers to Coffins"

 

[Jeff Liebermann]

On Sun, 16 Oct 2011 17:30:05 -0500, Jeffrey Angus <grendelair@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.


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

 

[spamtrap1888]

On Oct 16, 6:59 pm, Jeffrey Angus <grendel...@aim.com> wrote:

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."

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.