Thank you sirs for all the usefull inputs.
The problem was the coupling, bit rough and pulling the rotor, in combinaition with a slight missalignment.
Ran the motor not coupled and all was OK.
Thank you very much for all the answers.
Thank you very much for the replay.
@electripete
There are two motors on the same shaft, 30 degrees shifted. The LCI is driving both of them. Only one exitation
It drives a gear box.
@edison123
I do not hear any noise or banging. The motor runs smooth.
Could be a gap, pole, alignment problem?
I have a problem. I have a large motor, horizontal,(syncroneous)driven by an LCI. After one or two hours at high speed the rotor starts to slowly move back and forth. If I lower the speed the oscilations increases up to aprox 1HZ. What would be the axial forces doing that. I do not think that...
