Electric Motor Service Factor Amps

Franklin electric offers a full line of pumping systems to serve a wide variety of clean water applications.

Electric motor service factor amps.

Full load amps is the amperage at which the motor was designed to work at to achieve its rated horsepower. The americas water systems group serves north and south america. Most motors have a duty factor of 1 15 for open motors and 1 0 for totally closed motors. A motor with a 1 15 service factor can be expected to safely handle infrequent loads to 15 past it s rated horsepower.

Service factor is an indicator of the amount of overload a motor can be expected to handle for example a motor with a 1 0 service factor cannot be expected to handle more than its nameplate hp on a continuous basis. A service factor or sf is a factor representing the capacity at which a motor can operate without overloading or damaging its core or components. Most hazardous location motors are made with an sf of 1 0 but some specialized units are available for class i applications. Dc motors full load currents full load amps in 120 and 240 volts dc motors.

Traditionally totally enclosed fan cooled tefc motors had an sf of 1 0 but most manufacturers now offer tefc motors with service factors of 1 15 the same as on odp motors. To most it seems quite simple. For example many motors will have a service factor of 1 15 meaning that the motor can handle a 15 overload. Electric motor wiring 480 volt electrical motor wiring data nema amps starter size hmcp size for motors ranging 1 2 to 500 hp.

1 15 x 1 1 15hp anything above this load will certainly result in motor overheating and consequent damage of the ac motor. The reference point is a service factor of 1 which would mean a motor cannot operate over its rated horsepower or hp without overheating. The service factor sf is a measure of periodically overload capacity at which a motor can operate without damage. The nema national electrical manufacturers association standard service factor for totally enclosed motors is 1 0.

Motor service factor is probably the most misunderstood value on a motor nameplate. If it is a 1 0 you can run a motor to 100 load if it is 1 15 then it can be loaded to 115 of its rated load. Service factor amps is the amount of a periodic overload at which a motor can operate. Service factor amps this is the amount of current the motor will draw when it is subjected to a percentage of overload equal to the service factor on the nameplate of the motor.

A motor operating continuously at a service factor greater than 1 will have a reduced life expectancy compared to operating at at its rated nameplate horsepower. In the u s the defacto standard for ac motors is the nema standards. Typical service factors sf for ac motors.