Hello again.
Just to confirm that the vibration we see is exactly 1/3 x running speed. I have a time waveform that shows that every 3rd revolution I get a spiky peak.
There is a piece of literature from Bently Nevada that investigates rubbing in bearings and has mathematics (scary) and...
Hello all,
We have a 2400kW, 60Hz, 1185rpm motor with white metal oil-mist bearings that has a vertical radial vibration at 1/3 x running speed. The 1/3 x running speed peak is not sinusoidal and the horizontal looks more normal with only a small component.
It has no broken rotor bars...
Hello all,
I have been looking at a specification for low voltage (LV)3-phase ac induction motors. It specifies that all LV motors shall be connected in star and not delta.
I can understand the reason for connecting HV machines in star (economics of providing kV/mm for the insulation systems...
