Re-winding solenoids.

[Jeffrey Angus]

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.

Jeff-1.0

 

[Jeffrey Angus]

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.

Jeff-1.0

 

[Jamie]

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."




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.

I must say, you are an idiot!

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

Jamie

 

[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.

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]

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.

Jeff-1.0

 

[Jeffrey Angus]

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."

Jeff-1.0

 

[Jeffrey Angus]

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]

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.

Jeff-1.0

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]

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-1.0

 

[josephkk]

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.

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.

 

[Jeffrey Angus]

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

Jeff-1.0

 

[josephkk]

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

Jeff-1.0

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

 

[Jeffrey Angus]

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...

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

 

[Jeffrey Angus]

send me an appropriate percentage of the proceeds.

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

Jeff-1.0