Generator runs air conditioner, no AC current

[deltatango]

1984 Airstream 280
Onan Generator 6.5

Problem is there is no AC coach power when plugged into generator outlet.
Generator runs and runs one air conditioner but doesn't make AC power.
I checked breakers in back closet and checked breakers on Onan.
AC power works when plugged into shore power.

Thanks in advance.

[idroba]

The coach power works when plugged in to external power but nothing 120 volt related works when plugged into the generator outlet. Is that right?

And the rear AC unit runs when the generator is running, is that correct?

If so, here is my best guess:

The onan on those rigs has two windings, each with about a 30 amp output and each go through a little 30 amp push in breaker on the generator (which you say you checked).

It sounds to me like one of those two breakers is open, the one which supplies the generator outlet. The other one only feeds the rear AC unit, and must be working.

Those little Onan breakers are not really reliable. When I had my 310 I wound up bypassing them and putting a separate house stile 2 position 30 amp breaker box in the generator compartment.

If you have a meter, check the voltage on the input and output side of those two little push in breakers. I bet you will find one is open.

If power is getting through both breakers on the Onan, it has to be a problem in the #10 wire that goes to the generator outlet or the outlet itself.

Mine had an automatic transfer switch, which also could be the problem, but since you said you have a generator outlet, I am assuming you don't have an automatic transfer switch.

Last thought: If you have 120 volt power to everything but the front AC unit when on the generator, remember that there is a microwave/AC switch somewhere in the Kitchen. It must be in the AC position to make the front unit work.

[deltatango]

Originally Posted by idroba

The coach power works when plugged in to external power but nothing 120 volt related works when plugged into the generator outlet. Is that right?

And the rear AC unit runs when the generator is running, is that correct?

If so, here is my best guess:

The onan on those rigs has two windings, each with about a 30 amp output and each go through a little 30 amp push in breaker on the generator (which you say you checked).

It sounds to me like one of those two breakers is open, the one which supplies the generator outlet. The other one only feeds the rear AC unit, and must be working.

Those little Onan breakers are not really reliable. When I had my 310 I wound up bypassing them and putting a separate house stile 2 position 30 amp breaker box in the generator compartment.

If you have a meter, check the voltage on the input and output side of those two little push in breakers. I bet you will find one is open.

If power is getting through both breakers on the Onan, it has to be a problem in the #10 wire that goes to the generator outlet or the outlet itself.

Mine had an automatic transfer switch, which also could be the problem, but since you said you have a generator outlet, I am assuming you don't have an automatic transfer switch.

Last thought: If you have 120 volt power to everything but the front AC unit when on the generator, remember that there is a microwave/AC switch somewhere in the Kitchen. It must be in the AC position to make the front unit work.

Thanks, I'll start with those little breakers.

What is that box in the cabinet below where the plug to the generator is? It is like a breaker box. There is some stuff in it. What does it do? I suspect that thing is the problem.

[idroba]

Hmmmm, that sounds like you have both a generator plug and an automatic transfer switch. If so, the transfer switch is a very good possibility of being the problem. Can you take a photo of it? If it is about 6" square and about 3" deep and has 120 volt wires running in and out of it, it could be a transfer switch. The time delay system in them fail, as well as the relay contacts.

Mine had a cord reel, and I thought only those had a transfer switch, but maybe AS put them on all rigs, so there would be no load on the gen set when it was trying to start.

The one on mine was very hard to get at, and thus repair.

[deltatango]

Originally Posted by idroba

Hmmmm, that sounds like you have both a generator plug and an automatic transfer switch. If so, the transfer switch is a very good possibility of being the problem. Can you take a photo of it? If it is about 6" square and about 3" deep and has 120 volt wires running in and out of it, it could be a transfer switch. The time delay system in them fail, as well as the relay contacts.

Mine had a cord reel, and I thought only those had a transfer switch, but maybe AS put them on all rigs, so there would be no load on the gen set when it was trying to start.

The one on mine was very hard to get at, and thus repair.

Yes it is a transfer switch, manufactured by Todd Industries (30 amp).
Mine is easy to get to.
What does it do? Should I just replace it? $100
Thanks again.