I doubt you can just have arbitrary limits. It is not just one thing, but the whole system involved. This depends on the plant being used, and what you are willing to put up with, but it will be specified to some degree for a gen-set and motors. Generally larger motors need appropriate starters to limit the load on the genset (soft start). A VFD is one approach.

Generators sometimes have surge and peak ratings. Surge is often about double the KW and comes from the flywheel presumably.

You have to consider other things that might be getting powered too.

The second link provides a way to determine locked rotor current of a motor, and uses this to determine the generator KW rating. I suspect this is conservative, but with smaller petrol generators may not be.

If the surge rating is higher than the KW rating, some of this energy must be provided by the flywheel, and like power factor, all must be accommodated by the wiring. It is a matter of how much voltage and frequency droop is acceptable.

A stone crusher with a large flywheel of its own may need a starter or other starter to provide a slow buildup over a much longer time, and this would have to fit the normal maximum ratings of the gen-set.

Large motors may need a lockout to prevent them being reconnected while still spinning, as this can provide a larger startup surge.

The first link below has a reasonable discussion.