Thread: Lumpy motor when VFD running in vector mode drive.

Did you set all the motor parameters and perform a motor tune up cycle/sequence?

Originally Posted by BobL

Did you set all the motor parameters and perform a motor tune up cycle/sequence?

I probably should have been more specific.

The parameter values I listed are the motor parameters which I set, and then yes, I ran the auto tune function.

Just to confirm, to run the auto tune, I set the auto tune parameter then ran the VFD. It said “tune” in the display, buzzed for a little bit, spooled up the motor, ran for a bit then spooled down and stopped, and the display went back to the set frequency. I assume at this point the auto tune had completed.

I had an epiphany. What if the Rated Frequency parameter should be set to the motor's design frequency? So I set it to 50 Hz (instead of 100 Hz), ran the auto-tune again and all is well in Tasmania again.

I got confused between the Maximum Frequency to allow the VFD to run at and the motor's rated frequency. Seems obvious now.

I was just about to tell you to drop the rated freq to 50 Hz but I see you've sorted it out. Is this going on the lathe?

Yes on the lathe. I just need to get the spindle hole enlarged in the pulley.

Setting the base motor frequency too high will also produce lower motor power at lower frequencies.

In this test I did the reverse ie set the base frequency of a 50Hz rated motor to 29Hz.
This produced more power at lower frequencies compared to when the motor is set to the 50Hz base frequency.
The results are not complete at higher frequencies ie curves should all tip over at their peaks) but the trade off is loss of loss of power at higher frequencies.
HPVFWYE29HzBF.jpg
I believe this is not recommended as a long term solution so its better to adjust pulleys sizes to active the desired speed power combo - however for limited use its a lot faster to change the base frequency that to change the pulley.