AOU trouble shooting question

[Josh Atkinson]

Good afternoon and happy new years (Eve) to all. I am in the process of rewiring an AOU. I never got the chance to see if it worked properly before disassembly because the cord was in such bad shape. I have rewired and regreased it. It turns freely but as soon as you turn it on you can hear the power come to it and the blade just barely starts to turn and it locks up.  As soon as you turn it off it frees itself back up. 
 

it seems that I am missing something simple, I have done several others and have not had this issue. Does anyone have any ideas as to what is going on?

[Mark Olson]

The bearings may be worn to the point of allowing the rotor to contact the stator when the motor is energized. You may try turning the fan upside down and see if it runs. Sometimes loosening the end bells of the motor and bumping them around a bit helps.

[John Landstrom]

First thing I’d check are fiber thrust washers on the front and back of the rotor shaft.  
There should be enough on each end to center the rotor in the stater.   

I’ve had this issue and adding or subtracting to center the rotor fixed it.  Mine did the same thing.   The rotor would spin freely when off, but when current was applied is stopped and buzzed.  When I unplugged it and tried to spin the rotor I felt resistance until I moved the rotor forward.  (Not enough washers on the rear).  It might take some trial and error but it should help.   (Unless it’s an electrical issue.  Can’t help ya on those)

Note:  There should be a very slim metal washer that is slid onto the rotor shaft first, then the fiber washers, then another slim metal washer.  Same for both ends.  
 

 

[Josh Atkinson]

Thank you. I will try that

[John Nyman]

You can also try loosening the screws on the motor cover and sort of tap/wiggle/re-align the rear housing to get a slightly different angle, if you will, between the rotor and stator...this has helped me on many occasions when nothing else seems to work.