Service Factor and Service Factor Amps

Decades ago, when the electric motor industry was still in its infancy, a game of “one-upsmanship” played out between the various motor manufacturers. That is, one manufacturer would make its motor slightly more powerful than competitors’ motors of the same rating. In response, a competitor would increase the power of its motor, and so forth. It eventually became very difficult to compare motors from different manufacturers, and in time, standards were established and became known as service factor. Today, the National Electrical Manufacturers Association (NEMA) specifies service factors for electric motors, and different horsepower ratings carry different service factors. Continue reading