Power Factor

Dear All,

1 Voltage decreased

2 Torque decreased

3 Slip increased

4 Current increased to maintain the real power

5 Magnetizing current decreased because voltage decreased, then reactive power decreased.

Thus 4 and 5 will result increased power factor by reducing voltage.

The only difference is the frequenzy, If you run the motor on 60 cycles, it will run at 415V - If you run it on 50 cycles, it will run at 385V.

Thus it won't affect the power factor

The motor will only draw more current if you overload it, which is not adviceable.

Hope that this info will help.

Yes. For same output, motor MUST drawn increased current, since its "total Kilowatt" remains same. The reduction in voltage to a certain extent actually IMPROVES power factor since the "apparent" power is reduced. We know that Power Factor = Kilowatt / KVA which means once voltage reduces, KVA reduces & power factor improves. In fact on many energy saving devices, voltage is optimally trimmed to maintain a constant power factor. For a 415 volt 3phase ac squirrel cage induction motor, 385 volts is ideal & will not affect the power factor as far as my experience supports me.