A "C-Face" motor is a common American mechanical standarddesigned with a rugged flange on the face of the motor for mountingpurposes. The weight of the motor is supported by the flange,which is most commonly attached to a gearbox. The flange is strongenough to cantilever the motor. Naturally, this method is notuseful for large motors, and is rarely used over 20 horsepower.C-Face motors are designed to very tight specifications, and aredesignated by a "C" after the framesuch as 56C or 143TC sizes.