I work on very big VGT's

[Rawze]

Why is there a chunk of crud on that roller inside that bearing?


And WHY is that not a sealed bearing? - is there lube flowing thru the housing?. ... What RPM is it turning? ... and what viscosity oil is that bearing running on?.

I worked on, and helped design various types of industrial machinery like that for many years. that thing also looks like a permanent magnet DC? or a reluctance motor?. can be hard to tell just from a picture.

Also, is there a Tach-feedback on the motor to close-loop that VSD?.. or is it open loop and the VSD has no idea (guesses at) what rpm the thing is at? - I see that mistake a lot in industry with big DC drives like that ... Damned engineer who designs it don;t think it needs motor feed-back and then there are problems with surging, etc, later on.

-- ALSO... What type of dynamic braking system does it have on it?... and what brand/type of VSD is on it?... and how old? .. and Is that VSD protected with and a line-reactor and Amptraps (specialized solid-state fuses) on its front-end properly?

all the programming in the world will not make up for properly.. a poorly designed system.