A rolling steel mill loaned out a rotating converter generators set to another mill 30 years ago after 20 years use. It so now back after refurb but the landscape changed. It is a setup of 2 motors running 2 gen and a 15+T flywheel all on the same shaft, 750 RPM a couple of MW in total.
Anyway they "forgot" to balance the gen's after refurb despite rewind and new collectors... So guess what my work was supposed to be?
Well they found that something changed so the gen stators were a bit high and bolt bound so they got uneven air gap in all directions so they didn't dare to start, maybe they grown a bit in 30 years, a wasted 4+4 hour drive anyway.
So they put the old ones back again to start the mill as the guys were waiting to run the mill.
If they had dared to start I would have had some vibration indicating air gap problems I guess as it was maybe 1+ mm of error out of 3-4 mm gap. Would that really been a problem in the short term? Like until they were able to fix that "adjustment"? I think it was a good decision to swap back if the old generators could run for some time and I don't know the status of those.
Electrical guys were afraid that they could not setup collector adjustment so the magnetizing would be proper but I doubt that not knowing that much about it. What do you think, would it be possible to run it some months w/o destroying it?