Hello to everyone,
have you some explanations about the phenomena in the subject?
I'm sure about the nature of the 300 Hz, is electric, but I don't have any idea about the origin.
The motor is AC, is about 100 kW, and have 2 poles (about 3000 rpm), on the plant there aren't other motor with this phenomena and there aren't DC motor. The vibration level is quite low, about 4 mm/s rms (0,16 inch/s rms)