[Al Skierkiewicz]

There is no rule that specifies a breaker size for a motor.
The rules do require that CIM and FP motors must be controlled by a speed controller. Any legal motor can be controlled by a speed controller if variable speed and direction is needed for you application. CIM motors can be driven by a 20 amp circuit breaker if a team so wishes. However, the CIM motor may not provide the performance and the breaker will likely reset regularly producing a lot of heat in the breaker.