Code wise, the transformer size has to be 125% for the motor FLA, plus whatever for the controls load, I'd use (2) seperate transformers as the motor will make your power supply dirty. If you still want to use one transformer, use a 480v to 120/230v secondary and place the motor on one leg and the controls on the other, fuse your loads on the secondary side in addition to the primary 480volts side, ground your neutral point and you can always use a surge suppressor if your controls leg if they are electronic,