I have been working on a breakdown of a 1000Kw 750VDC motor in which the non drive end bearing failed. After fitting a replacement, the new bearing only lasted 2 hrs before failing. After replacing again, arcing was seen between the bearing housing and the motor frame, a bad earth brush was found on the shaft, repaired and the arcing has stopped. There is still significant magnetism being produced that is only present when the motor is turning (enough that a m16 x 100mm bolt can be stuck to the frame). My concern is that although arcing is not being seen, there is still current flowing through the bearing and going to again cause premature failure. All electrical testing I have performed on the motor is coming back clear. Looking for any tips/ideas of something potentially overlooked because everyone I’ve been in contact with is at a loss.
u/Wide_Ocelot_4118
Should a 1000Kw DC motor be producing enough magnetism to magnetise the platform it is sitting on and surrounding structure?
I have been working on a breakdown of a 1000Kw 750VDC motor in which the non drive end bearing failed. After fitting a replacement, the new bearing only lasted 2 hrs before failing. After replacing again, arcing was seen between the bearing housing and the motor frame, a bad earth brush was found on the shaft, repaired and the arcing has stopped. There is still significant magnetism being produced that is only present when the motor is turning (enough that a m16 x 100mm bolt can be stuck to the frame). My concern is that although arcing is not being seen, there is still current flowing through the bearing and going to again cause premature failure. All electrical testing I have performed on the motor is coming back clear. Looking for any tips/ideas of something potentially overlooked because everyone I’ve been in contact with is at a loss.