Just FYI for future reference:
A "quick and dirty" rule for generator sizing on 3 phase motors that has never failed me is if the motor is starting across-the-line, use 3X the HP as the minimum kW rating of the generator , 2X if it is a soft starter and 1.5X if it is a VFD. This is based on the reserve (starting) capacity of the average portable generator. So in your case if that is a 3 phase motor, I would use AT LEAST a 4.5kW rated generator.
If the motor is single phase, 4X for across-the-line, so if your motor is single phase, a 6kW would be the smallest that I would suggest (or whatever standard size is closest). But the soft starter and VFD issues are more complicated for single phase, not worth going in to here unless someone wants to know.