Axial movement of large synch motor
Axial movement of large synch motor
(OP)
I have a problem. I have a large motor, horizontal,(syncroneous)driven by an LCI. After one or two hours at high speed the rotor starts to slowly move back and forth. If I lower the speed the oscilations increases up to aprox 1HZ. What would be the axial forces doing that. I do not think that the drive is at fault. After cooling down, all is allright, for 1-2 hrs. There are no thrust bearings.
The motor just came from the shop rebuild.
There are to stator windings (two motors) 2000HP
Thank you,
Eugen
The motor just came from the shop rebuild.
There are to stator windings (two motors) 2000HP
Thank you,
Eugen





RE: Axial movement of large synch motor
What kind of coupling?
I don't know what that means. What is the relevance of a 2nd motor... it has the same problem or doens't have the problem or not running or... what are we supposed to do with the 2nd motor information.
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RE: Axial movement of large synch motor
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RE: Axial movement of large synch motor
Muthu
www.edison.co.in
RE: Axial movement of large synch motor
@electripete
There are two motors on the same shaft, 30 degrees shifted. The LCI is driving both of them. Only one exitation
It drives a gear box.
@edison123
I do not hear any noise or banging. The motor runs smooth.
Could be a gap, pole, alignment problem?
RE: Axial movement of large synch motor
Muthu
www.edison.co.in
RE: Axial movement of large synch motor
If you have thrust bearings in your gearbox and the motor shaft movement is more than than the small clearance of those bearings, , then you also must be experiencing flexing of your coupling (regardless of the origin of the force). If it's a shim pack coupling, and the oscillation occurs continously, you might think about fatigue (our oscillation only occurs during low flow condition that we don't operate in except during plant startup/shutdown). That's not a big deal, just make sure the shim packs get inspected once in awhile. If it is a gear coupling and you are seeing motor movement, I would be very concerned about the sliding wear that would be occuring.
By the way... what kind of coupling do you have?
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RE: Axial movement of large synch motor
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RE: Axial movement of large synch motor
The problem was the coupling, bit rough and pulling the rotor, in combinaition with a slight missalignment.
Ran the motor not coupled and all was OK.
Thank you very much for all the answers.