Hello

I have a problem that has appeared just after replacing an old Simoreg DC drive with a new DCM drive.

The problem starts after running the motor with load (no problem without load)

The motor makes quick vibrations and loud grinding noise.

I tried the Optimization runs, but nothing worked.

I decreased the gain from 10 to 3. And the noise disappeared.

Then it appeared again when I speeded up to half the rated motor speed.

Not as loud as the original noise, but you can hear it and feel the vibrations on the machine which shouldn't be there.

If i decrease the gain less than 3, the system becomes unstable.

In the attached image, the last step shows the higher fluctuations when the problem is occurring compared to the lower steps.

Drive: 6RA8075-6DV62-0AA0

Motor: 400V, 144A, 55kW, 1190 RPM

Appreciate your help