Gen running, but A/C units stop running

[creativepart]

We drove about 6 hours today. It's over 90 outside so, one hour before arriving to our stop for the night I started the generator so the A/C units could cool down the coach before we arrived.

About 40 mins into that last hour both of the A/C units stopped running BUT the genset didn't stop and never stopped running.

The first thing I checked was the thermostat. It showed 80 degrees inside and that both A/Cs were on and the fan was set to auto. The thermostat also showed that both A/Cs were set to 74 degrees.

The second thing I checked was the two 30-amp breakers on the Onan 5.5K genset and neither was tripped.

Not knowing what this could be, I turned off the gen and restarted it. It started right up. As soon as the power came on both A/Cs started running again. So, by this point we were 10 mins from the campsite.

As we drove another 5-min I noticed both A/Cs stopped again. I again restarted the gen (I have a start switch on my motorhome's control panel). Both A/Cs started again after a 5 min delay (typical for resarting A/C units).

By then we were at our campsite and I plugged into shore power. All has run normally since that time.

So, it's not an A/C issue. But what could it be? If it had been the generator's 30-amp circuit breaker then 1.) I would have seen it the first time I checked and 2.) it would not reset itself when started both times. Same applies for it not being the A/C circuit breakers.

I didn't check the power distribution display. And my inverter was on so, other 110v devices (clocks, etc) were still running, but they would off the inverter regardless.

Anyone have any ideas?

PS. Keep in mind the gen never stopped - just the two rooftop A/C units. So, it's not fuel nor anything generator engine related.

[Oregonpharme]

The issue your are experiencing is the 5.5KW gen set is inadequate to support both AC units, so they are shutting down from low power. There are solutions to this, and that entails installation of a large capacitor made for just this purpose in the AC power supply. Most of the larger RV centers will have the needed kit.

[bluepill]

The transfer switch may be failing and cutting out. When you shut off the generator then restart it, it cycles the transfer switch.

Inspect for any signs of overheating, and confirm that all wire connections are tight. Do this only with no shore power and with generator off.

Check youtube videos for help if you need it.