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Topic: Low power from genset to transfer switch (Read 593 times) previous topic - next topic

Low power from genset to transfer switch

Tested my auto gen start by turning on the microwave to draw down the house batteries.  Gen auto started OK with the auto gen start switch enabled.  However, as it turned out, the test must have damaged something as now when I turn on the genset manually,  power does not go to the coach.  Tested the transfer switch while genset was running and it showed only 11volts at the switch.  I understand a minimum of 100v is needed to trigger the transfer switch.  The shore power is working fine.  Look forward to a trouble shooting suggestion to resolve this issue as I will not get on the road without the genset working properly.
Fiddler
1959 Parris Island grad
40' 2001 U320 Build 5875
1999 Suburban K1500 toad
1986 Corvette Pacecar
ssoftail@comcast.net

Re: Low power from genset to transfer switch

Reply #1 –
Did you check and reset the breakers on the generator control panel?

Pamela & Mike
Pamela & Mike 97 U 320

"It's not what happens to you, but how you react to it that matters."

Re: Low power from genset to transfer switch

Reply #2 –
The 45 amp breakers on the control panel were not tripped; however, I turned them both on and off and resulted in no change.  Is it possible one or both could have burned out?  I guess I'll have to disassemble the control panel to get to the breakers to give a look.  thx pam and mike
Fiddler
1959 Parris Island grad
40' 2001 U320 Build 5875
1999 Suburban K1500 toad
1986 Corvette Pacecar
ssoftail@comcast.net

Re: Low power from genset to transfer switch

Reply #3 –
I would also check the connections to the ats from the genny under the bed too.
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Low power from genset to transfer switch

Reply #4 –
Turned the 45amp circuit breakers on then off a few times, power got to the transfer switch and all OK.  Turned the gen off and repeated the test;  this time the problem is back with no power to the transfer switch.  I put a meter on the circuit breakers with the genset running and with the breakers in the off position; they read 120vac yet no power to the transfer switch.  When I turn the breakers on they read 0vac.  Shouldn't this be the reverse?

I tried playing with the circuit breakers again and got it to work OK once more. Again, turned it off restarted; and the problem came back.    Faulty circuit breakers?  Regulator? (BTW where is the regulator?)
 
I may have fried the contacts on the circuit breakers when I tested the auto gen start by turning on the microwave....(it really drew down the batteries in a hurry) when the auto gen started the genset OK. 

Perhaps I should just replace both circuit breakers and see what results.  Any ideas?
Fiddler
1959 Parris Island grad
40' 2001 U320 Build 5875
1999 Suburban K1500 toad
1986 Corvette Pacecar
ssoftail@comcast.net

Re: Low power from genset to transfer switch

Reply #5 –
Quote from: Fiddler –
I put a meter on the circuit breakers with the genset running and with the breakers in the off position; they read 120vac yet no power to the transfer switch.  When I turn the breakers on they read 0vac.  Shouldn't this be the reverse?
...
Perhaps I should just replace both circuit breakers and see what results.  Any ideas?
How are you measuring the circuit breakers? One side to the other or output to neutral? Output to neutral should read 120VAC on, and 0VAC off. Across the breaker (from input to output) should read 0VAC when on, and 120VAC when off.

Circuit breakers do "get tired." If I found that switching the breakers a few times changed the output, I would install new breakers. I would not expect them to be expensive or difficult to replace.

However, the 10A breaker that controls the radiator fan on our generator got tired and would sometimes open for no apparent reason. The replacement was easy to do, but the single breaker switch was $100 from FOT. The only comparable part I had found was $65 from Powertech. I chose to buy from FOT because of timing, customer service, and customer loyalty. The new switch has operate properly. We've had no "surprise shutdowns" of the generator since installation of the new switch.
J D Stevens
1997 U295 CAI 36' Build #5085
2002 Subaru Outback
Motorcade 16869
Bellville, TX
 

Re: Low power from genset to transfer switch

Reply #6 –
Measured voltage on circuit breakers the correct way thx to JD Stevens;  and all measured OK.  Today, ran both breaker switches up a down a few more times; disconnected connectors and sprayed with electronic cleaner.  Reassembled,  retested and the gen ran fine after multiple tests.  Power at the transfer switch was 120vac and the EMS passed power to the coach OK w/no errors.  Not a definitive resolution but strong circumstantial evidence problem was in the contacts of one or both 45 amp circuit breakers.  I'll purchase a pair to keep as spares if/when symptoms revisit.  Sincere thx to all in the forum who took the time to provide guidance.
Fiddler
1959 Parris Island grad
40' 2001 U320 Build 5875
1999 Suburban K1500 toad
1986 Corvette Pacecar
ssoftail@comcast.net