lowest frequency output available from vfd

[electricpete]

Let's say were were doing a brief test and were not concerned about cooling or other effects on the motor.

What is the lowest frequency output available from a typical 480v 60hz-input VFD?

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[DickDV]

You can command zero speed with a VFD so that would be the equivalent of 0 Hz. The pulsing to the motor will actually vary slightly around zero but the net will be zero Hz or very near it.

 

[Marke]

Hi Electricpete

It does edpend on the VFD, some VFDs will operate right down to zero, while others switch the output off at around 0.5 Hz. I think that youwill find that the vector drives that can providetorque right down to zero Hz will give you this performance, while the V/Hz drives will tend to give no output at zero.

Best regards,

Mark Empson

http://www.lmphotonics.com

 

[CJCPE]

Remember that an induction motor must have slip to produce torque. If the motor is rated for full load torque 2% slip, it will need to have 2% of rated frequency to produce full torque at zero speed.