Your last generator Maintenance Run

[3930dave]

Just to make it more puzzling it appears that rectifier and varistor is integral to the coil, notice the 斗ump in the wrap. View attachment 671983

Just cost-effective packaging ?

You get to delete a separate pcb, and stabilizing bulky (compared to flakes-of-pepper SMD) components long-term in a vibration environment takes a bit more effort than it first seems it should.

Rgds, D.

 

[Industrial Toys]

AC to DC solenoids | Mike Holt's Forum

Some interesting things about AC vs DC coils that may or not be true. IF true, I think the answer is in there somewhere.

 

[RoyKing]

Your getting confused with power loading circuits which stage large loads via 24 volt AC Circuits.

You only need two wires to drive the transfer switch, 12vdc positive, and you trip it by grounding it.

The coils are driven off the line or generator and so when you ground the transfer switch nothing happens until the generator supplies power, after they close they are cutoff. When the line comes back on nothing will happen until ground is remove and line power will supply the coils and after it throws they are cutoff.

I wired one into a deep sea 7200 diesel line monitor controller

 

[Industrial Toys]

Much like my 200 amp ASCO switch. Emergency power drives solenoid to switch over main contacts. Switch is unable to operate in the absense of Utility or Emergency Power. Like, no back up battery supply or nothing. I haven't a clue if the coils are AC or DC.

Sill doesn't explain the bridge rect.

 

[Popgadget]

The linked forum on AC vs DC coils was interesting, but contradictory.
Here’s a little info on the differences, but I don’t see anything that would really favor DC except the tolerance for a stuck plunger.

Generally, DC solenoids are preferred to AC because a DC operation is not subject to original peak currents, which may cause overheating and coil harm with frequent cycling or accidental spool seizure.

However, where rapid response is needed or where relay-type electrical controls are used, AC solenoids are preferred.

The response time for AC solenoid valves is 8-5 μs compared to the typical 30-40 μs for DC solenoid operation.

The operating properties of a solenoid provided with DC and AC DC coils are significantly different in response time and can manage only small pressures.

In response time, AC coils are faster and can manage greater pressures at first.

They can therefore, if necessary, be cycled at quicker rates. However, electrical losses are greater and commensurate with the frequency of AC. (Power losses in an AC-operated solenoid with a frequency of 60 Hz, for example, are greater than that in a 50-Hz supply of the same coil).

 

[Industrial Toys]

I could also see the noise issue with AC coils if energized continuously. They can make a racket and do all kinds of goofy stuff with resonance. Last thing you want is a service call from a customer complained their thingie is "humming" keeping their goldfish awake!

Like the Tesla/Edison AC/DC debate. I guess AC coils are slso more suitable being controlled over farther distances with smaller gauge wire.

 

[Popgadget]

Your getting confused with power loading circuits which stage large loads via 24 volt AC Circuits.

You only need two wires to drive the transfer switch, 12vdc positive, and you trip it by grounding it.

The coils are driven off the line or generator and so when you ground the transfer switch nothing happens until the generator supplies power, after they close they are cutoff. When the line comes back on nothing will happen until ground is remove and line power will supply the coils and after it throws they are cutoff.

I wired one into a deep sea 7200 diesel line monitor controller

Agreed that you only need a 12VDC input to operate the transfer relay which closes the circuit through the limit switch from the 240VAC source to the coil. My question is why did Generac decide to rectify that and operate the coils with DC.

 

[Popgadget]

I could also see the noise issue with AC coils if energized continuously. They can make a racket and do all kinds of goofy stuff with resonance. Last thing you want is a service call from a customer complained their thingie is "humming" keeping their goldfish awake!

Like the Tesla/Edison AC/DC debate. I guess AC coils are slso more suitable being controlled over farther distances with smaller gauge wire.

Agreed on the noise, but these coils are only energized for a fraction of a second.

 

[Industrial Toys]

What's doing the switching in the controller? It's easier (on contacts) to switch AC then DC.

FWIW, I only installed one Generac propane run system, as a favour for a custoer at his cottage and that transfer switch apparently destroyed itself during a brownout. Maybe, that has something to do with it. I gather it operated back and forth until it failed. That was ten years ago and the equipment was used, older than that. Maybe a fix for that?

 

[3930dave]

Your getting confused with power loading circuits which stage large loads via 24 volt AC Circuits.

You only need two wires to drive the transfer switch, 12vdc positive, and you trip it by grounding it.

The coils are driven off the line or generator and so when you ground the transfer switch nothing happens until the generator supplies power, after they close they are cutoff. When the line comes back on nothing will happen until ground is remove and line power will supply the coils and after it throws they are cutoff.

I wired one into a deep sea 7200 diesel line monitor controller

Thanks for bringing that up Roy.... far enough back I'd forgotten what you used. Good general purpose controller, and IIRC, not badly priced.

Rgds, D.