You should post the exact specs for the fan you have, but GaGrown is right the motor needs a minimal amount of power to make the initial turnover happen. Your ultimate solution would be a variable-frequency drive.

YouTube - TEMCo How To: AC 120v Single Phase to 230v Three Phase VFD

I have the same issue, but in a 12v scenario. I'm going to experiment with using a timer that would run at full power for a few seconds then switch off leaving the regulated power to run the motor.