This is from our experience but as we all know these units can have their own pecularities.
We have a Power Tec 7000 driven via a Kubota Diesel. We have 50 amp service on a Dutch Star.
Only after about 8 years of service did I encounter this problem.
We were stopped at a Walmart for the night, it was 4:30 in the after noon 102 degrees in Columbia,SC. Both airs were running for about an hour and the generator just shut down. We don't have codes for this model so you are on your own to trouble shoot.
My first thought was maybe I was low on oil, so I checked it. They all have low oil sensors. Down maybe a 1/2 quart, so I topped it off. Started right up and ran for about 1/2 hour. Shut down again.
Still very hot, we went to eat some dinner. When we came back started up again no problem. This time it was cooling off so we only ran 1 AC. Ran all night no problem.
About a year late we were at the same location at the same time frame and the problem showed it self again, running two airs in extreamly hot weather. Shut down. So from experience I let it cool down and went to one AC. Again no problem all night long.
I talked to power Tec this time to get some answers. Come to find out, 7000 watts it on the edge of the curve for running two AC;s. It has a heat/overload sensor for the generator and in extreame heat two AC's will activate this sensor.
Now we know what the problem is, we run 2 airs to cool it down for 15 to 20 minutes and switch to one air for the evening and have no problems.
Later on Newmar went to 7500 watts on their units of our size. Probably for this reason.
Sounds like with 2 airs running you may be pushing your overload limit also.