onan generator air conditioning issue

[fritzcartage]

i have a wolfpack toyhauler with an onboard 4000 watt onan genset

the problem im having is about 2 yrs in the making

while at a steam engine show the gen stopped working

it was still running just no power for the rv

checked breakers all were good

in the gen comprtmnt a flex line comes out to a 4" box thats mounted to floor

on top of that box is a push button 30 amp breaker that was popped up

reset it all is good

from time 2 time it would pop and i would reset

i just figured it was under heavy load b/c it would happen on very hot days and the a/c was running

now it happens almost all the time like every 10 minutes

i crawled in the pass thru compartment and opened the 4" box

the neutral wire from gen to neutral wire of the rv was melted at the wire nut

cut off melted piece and reconnected with new wire nut & taped conections

still pops push button breaker

but now also pops 20 amp breaker inside rv

and also will just stop sending power to rv

gen still runs but it seems like the 110v/12v transfer switch is tripping

b/c it will switch from 110 fixtures running then loses 110 power for a couple of minutes and then "resenses" gen power and kicks back in

thanks in advance

 

[B.G. Smith]

Have you checked the rpm of the genset or the output voltage, sounds like it might not be up to correct rpm. bg

 

[TFucili]

Verify that the neutral/ground is actually good, not just connected. Use an amprobe to see what sort of current draw you are actually seeing. If there is not excessive current draw, then you'll need to track down a faulty component. If there is excessive draw, maybe the A/C unit needs attention.

 

[Bill Stockard]

Have you checked the rpm of the genset or the output voltage, sounds like it might not be up to correct rpm. bg

Check the frequency output of the generator. It should be 60 cycles. If the generator isn't running the correct governed RPM, it won't be producing 60 cycle AC current. Low RPM and less than 60 cycles puts a heavy demand on the genset from the AC motors in the A/C unit and will damage them.



Bill

 

[fritzcartage]

thanks for the advice

haven't checked rpm or voltage output

what would be the best way to check them?

how would i check the draw and verify the neutral is good?

and how to check the frequency?

i don't really know alot about electricity

thanks again

 

[B.G. Smith]

If the genset is running at design rpm the frequency will be correct, I expect that is 1800 rpm for the Onan. There is such a thing as a frequency meter but few and far between. Voltage can be checked with a volt meter across the circuit. The requirements for the AC unit are probably at least 105 volts @ 60 cycles. I have a reed type rpm meter and also a hand held meter that you can hold on the end of a shaft and read rpm's. A tachometer would also work if you had one for that application. bg

 

[Skydiver]

Some good advice from all.
To obtain a cheap frequency meter. If they are still made, buy an analog 120 volt clock with a second hand. First check it on your home current to be sure it is working correct. I call that "testing the testor". With your genset running take a stop watch and time how long it takes the second hand on the analog clock to cover one minute. It's as simple as that.
I suspect your breaker has weakened. They should not cost an arm and a leg to replace. I don't believe in "parts changing" buy I would try that first. An amp probe is very helpful in checking current.
Another test is to check for voltage drop. See what your voltage is loaded and unloaded. The voltage should drop a little when you load up your gen. Never run an inductive motor with less than 107 volts. Big no no.