Service Factor
Service Factor
(OP)
Hi Friends! i am new to this Eng.Forum.
I am working with a company manufacturing submersible pumps & i would like to know what is the difference in the electrical design between a motor with Service Factor & without Service factor, and also mostly service factor is declared for 60Hz motors & not in 50Hz?
I am working with a company manufacturing submersible pumps & i would like to know what is the difference in the electrical design between a motor with Service Factor & without Service factor, and also mostly service factor is declared for 60Hz motors & not in 50Hz?





RE: Service Factor
the reason why you don't see SF listed for 50Hz motors is because IEC, the governing rules for the rest of the world, make no such claim of a motor being rated for anything other than what it says it is. So in effect, all IEC motors are 1.0SF.
http:/www.jraef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Service Factor
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Service Factor
i read somewhere that a service factor motor is that the winding design will be with F class insulation but while running at full load the temperature rise will be equal to B class.The temperature rise will be equal to f class in SF load.is it true!
RE: Service Factor
http:/www.jraef.com
Eng-Tips: Help for your job, not for your homework Read FAQ731-376
RE: Service Factor
Also, all motor efficiencies and other performance parameters are based on operation at 1.0 not 1.15. All NEMA says is that the motor will operate satisfactorily at 1.15 - as jraef said.
As consultants, we typically specify a motor with a 1.15 SF, but require the bhp of the driven equipment should never exceed the nameplate motor hp under any operating conditions. We allow a 1.00 SF motor if the bhp never exceeds 87% of the motor nameplate horsepower - but we don't see that option used too often
RE: Service Factor
The following was taken from NEMA MG1 standard:
“A general-purpose alternating current motor or any alternating current motor having a service factor is suitable for continuous operation at rated load under the usual service conditions given in part 14. When the voltage and frequency are maintained at the value specified on the nameplate, the motor may be overloaded up to the horsepower obtained by multiplying the rated horsepower by the service factor shown on the nameplate.
When the motor is operated at any service factor greater than 1, it may have efficiency, power factor and speed different from those at rated load, but the locked rotor torque, current and breakdown torque will remain unchanged.
A motor operating continuously at any service factor greater than 1 will have a reduced life expectancy compared to operating at its rated nameplate horsepower. The service factor load reduces insulation and bearing life. “
RE: Service Factor
As my job is related with Submersible pumps & motors(deepwell) can anyone of u please tell me what will be the class of Insulation of Water filled rewindable submersible motors (Winding is made of water proof insulated copper wire). Normally manufacturers claim it as Y class?
But i have never seen anywhere the temperature ratings for Y class insulation.