# 400 Hp. Ac - Motor Of 60 Hz

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Dear Sir,

I am having a motor of 400 HP. 3 Phase, 60 hz, 400 volts.

but in our country we are having 50 hz, will the motor work.

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Hello PANKAJ GUPTA

If the motor is of Japanese origin, it may be designed to work on either 50 Hz or 60 Hz, otherwise it will probably be a dedicated design for 60 Hz.

In order to operate a 60Hz motor on 50Hz, you must reduce the terminal voltage to keep the flux constant. This means that if the motor is designed for 400 volt 60Hz, then you can run it at 400 x 50 / 60 = 333volts at 50 Hz.

The ratio of V/Hz must remain the same. 400/60 = 333/50.

The end result of running this motor at 50 Hz 333 volts, is that the speed wil reduce to 5/6 of the rated speed, and the power rating will reduce to 5/6 of the power rating.

There fore, if this was a 4 pole motor, the speed would drop from aroun 1760RPM to 1467 RPM and the power would drop from 400HP to 333HP.

One way to bet rated speed and power, is to use a VFD so that you can run it on 400V 60Hz.

Best regards,

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Hello PANKAJ GUPTA,

If you want to know what happen if you run that motor on 50HZ without reducing terminal voltage, please read the following;

"Don't assume any thing, always check/ask and clear yourself".

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