Question
I have a 1.5hp irrigation pump running 6 heads and everything works - except - I am running the motor from a 3500 watt generator and the motor runs fine for about 30 minutes, then it over heats and the capacitor will blow. I have replaced the motor and it does the same thing. The problem seems to be the power source, could this be true?

Answer
The problem is the number of heads / the size of the pump. Not the power source. you are trippimg the capacitor in the pump-correct. If true, it is just overheating.  then the easiest thing to do and the least costly would be to reduce the gallons per minute out of the heads.-if possible. The pump is trying to pump more water than designed for.
You could go to a 2 h.p. pump, but then you have to think about a 220 vac breaker. and the wire to it needs to be 14 gauge, (bigger), probably. You can get a 2 hp pump that is 110 vac, but it will pull 20- 30 amps and use more electric. See if ther ir a way to go down on the nozzle size in the head, or let me know what kind of heads you have. Jim