IMO, if you can honestly say you would never need to work on it energized, there is no working space requirement.
110.26 (A) Working Space. Working space for equipment operating at 600 volts, nominal, or less to ground and likely to require examination, adjustment, servicing, or maintenance while energized ...
I have never seen a "working space" for motors in the code book. However, make sure the moving parts are guarded, you have easy access to the motor connection box and you allow space for proper ventilation.