I want to convert my lathe to an ajax controler but my Z axis motor is too big for their drives. they recommend an amc drive and their gpio4 controler package. My problem is I really dont know how big a drive I need. The plate on the motor says its a 17.8 amp. ( its a 1200 in/oz servo motor ) would a 20 amp drive be big enough or do I have to go with the intermittant current?