General Purpose AC Motors

NEMA 56 frame three-phase general purpose AC motors have a standard 5/8″ diameter, 1-7/8″ length shaft whose center is 3-1/2″ above the base mounting surface. Variations to the frame’s standard dimensions and design are indicated by a letter designation following the frame number, such as 56HZ or 56C. The letter ?H? indicates that the frame has a set of mounting holes at 3″ and 5″, ?Z? indicates that the frame has a nonstandard shaft, and ?C? indicates that the motor can be face mounted. These frame standards and letter designations are defined by the National Electrical Manufacturers Association (NEMA).