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motor power factor


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#1 ram14375

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Posted 03 February 2006 - 04:50 PM

we have got one 11kv,2650kw,0.83 pf(at full load),96% eff ,174 amps Flc slip ringmotor
we measured the power and noticed the power factor 0.86.The motor was running at full load.
can the motor power factor exceed the rated power factor.

This motor is supplied from our substation bus(11kv) which has capacitors installed in the bus section.
thanks
ram

#2 marke

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Posted 03 February 2006 - 07:26 PM

Hi ram

The power factor on a motor is a function of the magnetising curent. If the magnetising current is low, the power factor will be higher. If you reduce the erminal voltage to the motor, the magnetising current wil drop and the power factor will rise.
I suspect taht the terminal voltage at the motor is lower than specified.

Best regards,

#3 ram14375

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Posted 04 February 2006 - 05:28 PM

sir,
during the measurement we maintained the voltage as 11kv and the frequency was at 49.6hz(rated 50).but the meter read it as 0.86.My question is whether inclusion of capacitors at the bus section(upstream) will increase the overall powerfactor as there is only cable from the substation to load station of the motor.

Whether inclusion of capacitor will increase motor power factor ,
can the power factor can be more than the specified in the test record or name plate.
we used a krykard power analyser for the measurement..
thanks
ram

#4 ram14375

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Posted 04 February 2006 - 05:48 PM

sir
wiill bulk pf correction improve the moto power factor
ram:):mad:;c;;c;

#5 marke

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Posted 04 February 2006 - 07:01 PM

Hello ram

Bulk power factor correction will not alter the power factor of the motor measured at the motor. The effect of power factor correction is only measured on the supply side of the correction. Between the motor and the correction, there will be no difference except that the voltage may be higher than if there was no correction at all.

Best regards,




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