We have 15 MW 4 Pole Generator. The rotor of this generator is failure 6 times in a year. The excitation voltage and current are increased after repairing of rotor. The rotor shaft vibration is high

 

> We have 15 MW 4 Pole Generator. The rotor of this generator is failure 6
> times in a year. The excitation voltage and current are increased after
> repairing of rotor. The rotor shaft vibration is high

First thing first. What kind of prime mover? If it is a hydro turbine (most likely not) what is its configuration? I mean vertical or horizontal shaft?

 

Rotor failure 6 times a year???

Without having the answer for at least the following, I think no one could provide a clear opinion:

1. What is the cause of the high vibration?

2. What work was carried out before and after the first failure?

3. Was the work carried out by OEM or any generator specialist?

4. Since we only install the vibration probes on the bearing housing, was all the vibration through out the machine train picked up high values or was it just the generator bearings?

5. Was the alignment of the generator carried out according to specifications?

6. Was there any other failure occur during the rotor failure?

 

Please ensure the lub oil pressure also at both the DE & NDE bearings. Is their any fluctuation in oil flow?

 

GDD.... the intro to your post discussed lead failure.

If they are stator-winding terminating leads, then either they are improperly supported to resist movement or flexing, or wire size is too small.

If they are connecting field-coils of a salient-pole machine, then inspect for pole movement, wire movement, or wire flexing.

Phil Corso