Good Morning,
Can anyone give me links to literature pertaining to the effects of running a motor off of its magnetic center? I have a customer requesting data " in writing" the detriments of running of center, and the effects (either immediate or long term) it would have on the application. I wasn't sure which board to post this one on, but they want info on the electrical (motor) and mechanical (alignment, effects on bearing health, etc)
Thanks in advance for any help
Jeff

Hi Jeff3. Presumably this is a large, sleeve bearing motor?
Firstly, why does it have to run off its magnetic center. Has it been assembled wrong?
We had a 1200hp motor running off center for two years and the only "problem" we encounterd was that it "hunted" axially, trying to maintain its center. As it was driving through a gear coupling there was sufficient play in this to allow this to happen and for the movement not to be transferred to the driven machine.
I've checked all my manuals, and on the internet, and can find nowhere where this is written up.

I did see one problem with this where the magnetic center pulled the motor shaft over to the point where the motor shaft and driven shaft would knock in the coupling. The machine didn't run too long this way but I'd think that knocking the shafts together and bouncing back would not be a good situation long term.

Jon
Spintelligent Labs

Hi Jeff

Check this link :

http://findarticles.com/p/articles/mi_qa3726/is_199801/ai_n8789578

MarkoLeo

If it 'free-floats' and the coupling has room to 'free-float' then the motor will 'hunt' or 'seek' as some say but the occilation really isn't hurting anything. But to exceed the limits and then you're bumping something either in the motor, coupling, driven unit or all. Like the gear coupling and a sleeve driven machine; the coupling has more axial float so the thrust bearing in the driven machine carries the load and can fail depending on a number of factors one being how level are you sitting; are you pulling or pushing? Also try making your check on peak public power draw on the A leg.

Thanks for the information. I have been swamped this week, and have not looked into it any deeper. Will post any new info when I get it.
I dont know why motor was installed to run off its center. --That was my first question as well.--- it is a large motor, with a limited float coup. More to follow-
Thanks Again, Jeff