With motors, there's an additional factor to consider.
The start-up surge when turning on a motor can briefly be many times the steady-state rating of the motor. It's short enough that it doesn't always blow the breaker, but it's hell on the inverter. An electrician told me that when using an inverter to run a motor, as a rule-of-thumb the inverter's rating should be
six times 
the motor's rating to prevent early failure of the inverter!