Gary,
Until folks who know the subject better than I do log in, a few general suggestions:
220v lines not only have a duplex circuit breaker (should, anyway) but sometimes have two separate fuses. There are also two separate fuses internally in most good units.
So check that you are getting 220 at the socket and to the motor.
Perhaps a capacitor has blown? I do know that these motors have to deal with some major pressure, so have starting help. Oh, right - something stuck open or closed or blocked in the air flow path?
If that isn't the case, then you need to see what steps the motor goes through in ramping up. Is there some sort of centrifugal switch which has to be satisfied before the second stage comes up? Or an electronic sensor to check speed/load? It could just be a loose cable or sensor out of alignment.
Or maybe there is an out of range problem with the blowers, preventing the motor from speeding up - when it tries to, a sensor "sees" that something is blocked or loose or out of balance and won't let it get up there.
These are really just common sense, general problems - I don't know enough about your specific set-up to suggest more. But at least these will get you going. Oh, one thing which you should be careful of. If a mouse has chewed through a wire or one has come loose, there could be dangerous voltage levels exposed. A danger to you and the equipment.