# 480 motor on 575 vfd



## Tsmil (Jul 17, 2011)

I'm just want to confirm if you can run a 480 volt motor from a 575 volt vfd just by programming in the motor specifications. The vfd is connected to a 575 source.


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## just the cowboy (Sep 4, 2013)

*Should be no problem*

I run 380 volt motors on 480 volt supplied drives all the time, nameplate data should be all you need.


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## JRaef (Mar 23, 2009)

That will depend on the motor. The DC bus is the line voltage x 1.41, so on a 575V supply, the DC bus is going to be 810VDC. That means all of the PWM pulses will be 810VDC no matter what you program the RMS voltage output to be. That will be hard on a 480V wound motor, and even worse if there is any distance between the drive and motor where standing waves could be created. If it s a good quality "inverter duty" motor with 2000V magnet wire, it's probably OK, but if not, you will likely see the insulation fail in short order.

In a 380V motor, they will use the same insulation as a 460V motor so it's not a big deal, but most 460V motors are not built to be connected to anything higher. If it were me, I'd evaluate this based on the cost of unexpected down time. If thats no big deal, I'd use it since I already have it and when it fries, replace it with a 575V motor. But if a couple hours of down time will cost more than a motor, I'd replace it now..


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## Tsmil (Jul 17, 2011)

I'm hoping a 2 hour test will do no harm. It currently is our only option to run the test. Customer is going to have to invest in a 480v drive for future tests. 480 is not too common here.


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## JRaef (Mar 23, 2009)

Oh, you didn't mention that.
Sure, go ahead. I test 240V motors with 480V drives all the time.


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