TABLE OF CONTENTS NEMA is the National Electrical Manufacturers Association, a nonprofit trade organization supported by manufacturers of electrical apparatus and supplies. NEMA standards are designed to eliminate misunderstandings between manufacturer and purchaser. NEMA also assists purchasers in selecting and obtaining the proper product for their particular needs. Some standards included in the NEMA Standards for Motors and Generators have frequent application in the air conditioning, heating, ventilating, plumbing, and fire protection fields. Portions of these standards are described or repeated in the following pages. Reference will be made to these standards in other parts of this section.
The following are NEMA criteria for motor classification:
Classification by Size. A motor may be classified as either a fractional horsepower motor or an integral horsepower motor.
Classification by Application. Motors normally are classified under one of the following application designations:
General-Purpose Alternating-Current (ac) Motor: A n induction motor of open construction, with standard operating characteristics and mechanical construction, for use under usual service conditions without restriction to a particular application or type of application.
Definite-Purpose Motor: A motor having standard ratings and standard operating characteristics or mechanical construction for use under service conditions other than usual, or for use on a specified type of application.
Special-Purpose Motor: A motor with special operating characteristics or special mechanical construction, or both.
Industrial Direct-Current (dc) Motor.
Classification by Electrical Type. The following electrical motor types are recognized:
ac induction motor
ac wound rotor induction motor
