Hi
We have one of the KEB COMBIVERT F5 inverter drives on one of our machines. The output voltage from the drive when the motor is running should be 120VAC(phase to phase), but we are getting 220VAC(phase to phase). Also, in stand still condition there should be no output voltage to the motor but we are getting around 40VAC(phase to phase), causing the motor to hum and in some instances rotate in the reverse direction. Input voltage is 415VAC.
What could be the possible cause of such behavior?
Any information and help would be greatly appreciated. Thank you.

 

Evidentally that is not your regular induction motor style VFD, it caters to synchronous and servo type motors of different types.
You would need to download the manual and try tuning via the parameters involved.
Why was not a regular style VFD used if this is a common induction motor?
Max.

 

Can you draw a circuit please.
Is your control circuit "start-triangle" ?

https://www.allaboutcircuits.com/te...t/chpt-10/three-phase-y-delta-configurations/


EDIT:
My guess would be a wrong wiring, as the voltage can not rise to 220VAC by itself.

 

Can you draw a circuit please.
Is your control circuit "start-triangle" ?

.

I have never seen a Star-Delta start from a VFD, and suspect it would never be necessary?
Max.

 

I have never seen a Star-Delta start from a VFD, and suspect it would never be necessary?
Max.

There must be something wrong with the wiring or control that supplies the voltage? What else can cause a permanent voltage of "220VAC" and not just some temporary spike?

 

It would help if the nature of the motor was shown, typical squirrel cage induction motor etc...
It almost sounds like the 40v is a 'servo-ing' voltage?
A typical VFD is uni-direction by selection.
Max.

 

It would help if the nature of the motor was shown, typical squirrel cage induction motor etc...
It almost sounds like the 40v is a 'servo-ing' voltage?
A typical VFD is uni-direction by selection.
Max.

A circuit should help.

 

Sorry for not replying.. the problem seems to have been sorted tuning some parameters on the drive.

Thanks for the response, appreciate it.

Cheers.