Motor starting is one of the major applications of both prime power and standby generator sets.
Years of experience in successfully applying generator sets to motor loads leads us to the conclusion that the subject is often complicated beyond necessity. The basic characteristic of motor loads that causes difficulty is that motors draw high starting currents when started at full voltage. These code letters range from A to V, covering motors with a locked rotor KVA per horsepower of 3.14 or less to 22.4 KVA per horsepower or more. Small motors commonly have a higher NEMA Code letter and corresponding higher locked rotor KVA per horsepower requirement than large motors. Typical Code Letters for Various HP Motors Fractional horsepower motors usually have even higher locked rotor KVA requirements.