Electric Motor Service Factor Amps

Electric motor wiring 480 volt electrical motor wiring data nema amps starter size hmcp size for motors ranging 1 2 to 500 hp.

Electric motor service factor amps.

In the u s the defacto standard for ac motors is the nema standards. The service factor amperage is the amount of current that. 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. For example many motors will have a service factor of 1 15 meaning that the motor can handle a 15 overload.

To most it seems quite simple. A motor with a 1 15 service factor can be expected to safely handle infrequent loads to 15 past it s rated horsepower. Most hazardous location motors are made with an sf of 1 0 but some specialized units are available for class i applications. Motor service factor is probably the most misunderstood value on a motor nameplate.

Franklin electric offers a full line of pumping systems to serve a wide variety of clean water applications. Service factor amps is the amount of a periodic overload at which a motor can operate. The nema national electrical manufacturers association standard service factor for totally enclosed motors is 1 0. 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.

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. 1 15 x 1 1 15hp anything above this load will certainly result in motor overheating and consequent damage of the ac motor. For example the maximum motor load for a 1hp electric motor with a service factor of 1 15 is. Most motors have a duty factor of 1 15 for open motors and 1 0 for totally closed motors.

Dc motors full load currents full load amps in 120 and 240 volts dc motors. Typical service factors sf for ac motors. The reference point is a service factor of 1 which would mean a motor cannot operate over its rated horsepower or hp without overheating. 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.

The americas water systems group serves north and south america. The service factor sf is a measure of periodically overload capacity at which a motor can operate without damage. Electrical electrical units amps and electrical wiring wire gauge and awg electrical formulas and motors.