Old Generac ATS

[Seven-Delta-FortyOne]

Looked at this one today. There are 4 ATS powered from 1 generator.

He said the system worked for 20 years, and then a couple years ago the farther 2 stopped transferring.

They ran new wires between them, guess it worked for a while, and then stopped again

They ran 12-3 UF cable overhead, between the first two and the farther two.

Two conductors are used for N1 and N2, (240v utility sense) and 2 are used for 23 and 194 (12 volt).

There is 12.6 volts at the first two ATS, and 7 volts at the last two. Then the last two are paralleled with the lamp cord you see here.



Im wondering what that contactor above the fuses is. It appears to be a relay, but I’m not positive what it’s for. Is this a standard part in the older Generac ATS, or was this perhaps someone’s attempt at adding a relay?

At any rate, it’s not placed where Generac requires it for powering more than two ATS.

And the run is only about 50’, so I’m not sure why the excessive VD.

 

[ppsh]

23 and 194 are the only wires that paralleled unit to unit form the "master ats". The zero wire as well on newer units is a 12v ground for the load shed module.

Controller in the generator sees a power loss on n1 and n2. Generator cranks, reaches operating speed. Controller grounds the 23 wire to 12v ground to power the relay coil allowing the 240v from the generator to power the solenoid, transferring to emergency.

N1 and N2 are only to be connected to one ats.

Chances are the overhead splices are bad.

 

[Birken Vogt]

N1 and N2 are only connected at one ATS, as stated above. Otherwise you will have all your utilities in parallel (through the 5 amp fuses) and likely blow fuses or cross phases and really blow fuses.

23 is +12VDC from the generator battery. 194 is switched ground from the generator controller. When it wants transfer to occur it grounds 194. Otherwise 194 is left floating and rises to +12VDC potential when metered.

Generac states up to 2 transfer switches can have their DC circuit paralleled in this way. Any more than that and you need to add slave relays and such. Not allowed to have 4 relays' return current all sinking to the controller.

The ice cube relay you reference was standard equipment until they came out with the printed circuit board found in the current models. 23 and 194 are across the coil. The relay contacts energize either the up coil or the down coil of the transfer switch with 240 volts when it wants the switch to move positions.

 

[hillbilly1]

Check for burnt contacts on the cube relay. Also 12 vdc when generator calls fo transfer. That relay fails the switch to normal position. Those solenoids are known to fail too if the clearing contact micro switches on the side stick closed.

 

[Birken Vogt]

Those coils draw about 1kw as long as they are energized. They only energize for a fraction of a second normally. But if they get hung up or the micro switch fails, they burn up right quick.

 

[Seven-Delta-FortyOne]

I had considered the coil being bad, but that wouldn’t account for the pretty significant voltage drop present.

And it’s happening with both the ATS that are grouped together at the farther location.

 

[hillbilly1]

I had considered the coil being bad, but that wouldn’t account for the pretty significant voltage drop present.

And it’s happening with both the ATS that are grouped together at the farther location.

What is the distance to the further ATS’s? Could be a combination of voltage drop, and the relay(s) being a pig and failing? Disconnect one and see if the voltage goes back to normal, if not try the other one.

 

[Seven-Delta-FortyOne]

Distance is around 50 feet.

 

[Seven-Delta-FortyOne]

So I found this wiring diagram from Generac showing the required relay.

What I don’t understand though, is it doesn’t appear that it will counteract VD at all, as it’s a straight 12v relay.

 

[hillbilly1]

So I found this wiring diagram from Generac showing the required relay.

What I don’t understand though, is it doesn’t appear that it will counteract VD at all, as it’s a straight 12v relay.

It is, the generator sends 12 vdc to that relay that energizes the source two solenoid, which switches it to generator power. The microswitches interlock the solenoids so only one is energized at a time. If the relay is is a long distance from the generator, and the wire is small, the coil voltage can suffer when energized. If the relay coil is drawing more power than normal, it can also cause a severe voltage drop.

 

[Seven-Delta-FortyOne]

Ran a quick voltage drop Calc for 12.6 volts on #12 wire, and it would have to be so ridiculously long to ever get 5+ volts dropped.

There must be something else going on there.

He’s had so many relatives and friends and “electricians“ messing around over there, that I’m probably just going to give him a quote to take it all out and redo it.

 

[hillbilly1]

Ran a quick voltage drop Calc for 12.6 volts on #12 wire, and it would have to be so ridiculously long to ever get 5+ volts dropped.

There must be something else going on there.

He’s had so many relatives and friends and “electricians“ messing around over there, that I’m probably just going to give him a quote to take it all out and redo it.

That’s why you need to pull each relay to see if the voltage changes. If the coil is shorted, it can draw quite a bit of power. Starting with 12 volts, you don’t have a lot to play with on the load side.

 

[kwired]

Ran a quick voltage drop Calc for 12.6 volts on #12 wire, and it would have to be so ridiculously long to ever get 5+ volts dropped.

There must be something else going on there.

He’s had so many relatives and friends and “electricians“ messing around over there, that I’m probably just going to give him a quote to take it all out and redo it.

What current level did you use? Bad coil or sticky armature in the relay could cause increase over what is normal current for the relay.

Doesn't take much VD to be considered a significant amount on 12 volts which also could result in excess current and heating in the coil.

 

[Seven-Delta-FortyOne]

I ran several calcs with amperage’s from 1-40.

 

[kwired]

I ran several calcs with amperage’s from 1-40.

40 amps on 12 AWG at only 12 volts and 50 feet length and your results had no VD issues?

 

[farmantenna]

N1 and N2 are only connected at one ATS, as stated above. Otherwise you will have all your utilities in parallel (through the 5 amp fuses) and likely blow fuses or cross phases and really blow fuses.

23 is +12VDC from the generator battery. 194 is switched ground from the generator controller. When it wants transfer to occur it grounds 194. Otherwise 194 is left floating and rises to +12VDC potential when metered.

Generac states up to 2 transfer switches can have their DC circuit paralleled in this way. Any more than that and you need to add slave relays and such. Not allowed to have 4 relays' return current all sinking to the controller.

The ice cube relay you reference was standard equipment until they came out with the printed circuit board found in the current models. 23 and 194 are across the coil. The relay contacts energize either the up coil or the down coil of the transfer switch with 240 volts when it wants the switch to move positions.

your numbers 194 & 23 are transposed.

 

[Seven-Delta-FortyOne]

40 amps on 12 AWG at only 12 volts and 50 feet length and your results had no VD issues?

At 40 amps I finally got the VD I was seeing in the ATS.

 

[hillbilly1]

It’s almost like they have the last two in series? I don’t think the controller would be capable of 40 amps.

 

[hillbilly1]

The more I think about it, the more I believe that’s what they done. The last two relays are wired in series with the control output, that’s why you are getting almost half the voltage at the relay, making it appear as a severe voltage drop.

 

[Seven-Delta-FortyOne]

I was swamped last week, 12 site visits in 2 days, missed the main breaker on the panel in my Code violation thread, big remodel going on and a few service calls, and trying to bid a bigger (for me) PW job.

When I was at this site, I didn’t have time to pull it all apart, I was there for a Kohler that the installer never hooked a battery charge circuit to.

He called me this morning and said they lost power last night, and when utility was restored, the coils in the master ATS were “banging“, and possibly switching back and forth.

Oh, and he said they added a T1 wire to this genny about a month ago. A “father in law” or someone.

Sounds like a complete disaster down there, I told him I’ll try to get down there next week and just start pulling stuff apart and testing, and try to see what he has going on.

I do know that there is N1and N2 wires connectors in every ATS, which is not needed, nor is it ideal.

Im thinking that you are right about those relays wired in series. He said it’s worked for 20 years, and now doesn’t, but it’s hard to pinpoint just what has been messed with by his hodgepodge of “electricians” he’s had down there.