AC Generator shaft circulating current problem

[280658]

is causing the main engine bearing to fail.
Would this be possibly due to a recent rewind and generator stators core repair, the stators winding is as manufactures specifcations;But the stators core pack has been repaired a couple of times.
Would you expect a magnetic inbalance?.

 

[HIB]

Shaft currents are most often associated with 3600 RPM synchronous machines. The problem is associated with harmonics generated by the switching power SCRs in the excitation system that applies power to the field of the generator. A solution is placing a voltage shaft suppressor across the field, center tapped to ground. See
Technical paper, "Application of Static Excitation Systems for Rotating Exciter Replacement" at Basler web site

http://www.basler.com,

"Technical Resources" for more information.

 

[GusD]

Hello 280658

When you mention "main engine bearing failure" I believe you are talking about the main bearings on the "crank shaft".If I am not in the right track ,please just disregard the post.Not long ago I was contacted by someone that works for a Mobile Division where Electric trucks are commonplace. (trucks with AC drives).This individual sent me several slides of failed Mains bearings.The Manufacturers of the Engine/Truck is working hard to solve this problem.
The most interesting thing about this is the fact that these trucks come with 2 different engines(Different manufacturers)The truck with one make of Engine, has no bearing problems,the other truck with the other Engine seems to have all the baring problems.No solutions so far.
Interestingly enough, the bearings on the wheel drive motors are not being affected by this problem.

I hope this falls in line with your question.I believe that it might be easy to correct this problem if in fact the damage is caused from shaft currents.I still don't have enough info on this problem as yet. Normally we are dealing with problems related to electric motor bearings being damaged due to circulating shaft currents.In this case the problem is the Engine bearings themselves.

Good luck +=29


GusD