RV Repair: shore power versus generator, winnebago chieftain, amp service

Question
when my rv is plugged into the generator both roof ac's work at the same time (1989 winnebago chieftain 31rq)  but when I am plugged into shore power Only one of them can be worked at a time?  Is there any way (cheaply) to make both of them work at the same time when plugged in?  I have only a 30amp power cord.  thanx

Answer
William, I am sure there is a way that you can do that but there is not any safe way to do it without changing to a 50 amp service cord. The reason you can do it with the generator is probably because it is a 5 kwh or better generator. It is not a good idea to over amp the rating of the wiring. I am sorry this is not better news but safety is always the best way to be. Thanks, Bill