Brushless motor not spinning (help)

Thread Starter

oidium45

Joined Apr 24, 2010
136
Hello, i have a few 120v fans that use a brushless motor. Both have stopped rotating. Even when you try spinning them by hand while on they do not rotate. I have taken them apart and cleaned them up throuroughly including lubricating the bearings. Still, nothing works. Anyone have any ideas? Or are they just toast?
 

#12

Joined Nov 30, 2010
18,167
I don't know your skill level, so please don't be offended.

Two "known good" parts in a row refusing to work suggests you made an error with the 120V and will have this fixed b4 I can reply.

However, when a brushless fan goes bad, It is really difficult to do anything about it. Do you have a microscope and surface mount soldering? I didn't think so. They are frisbees.

There's one opinion.
 
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Thread Starter

oidium45

Joined Apr 24, 2010
136
No, i thought it was necessary to specify that these were not motors that wound myself.. These were motors that recently stopped functioning. I am hoping that someone might have a trick to getting them working again. Although, i suspect that one or more of the windings may have shorted over time causing the current problem with them not opperating. This is a last resort before throwing them out and replacing them with new motors...

Thank you for your reply
 

SgtWookie

Joined Jul 17, 2007
22,210
It would help to have some good photos of the motors. If that isn't easy for you to accomplish, do you have a manufacturer and part number for them?


If the fans had been in a stall condition previously due to frozen bearings, running slowly or otherwise been in a "locked rotor" condition, the windings may have burned up due to overheating. There also may be thermal fuses that have opened up; if the motors are small (like computer fan size) the fuse might look sort of like a diode with a metal cylindrical case. Larger motors might have a thermal fuse that looks sort of like a small TO-3 case screwed into the motor frame.
 

#12

Joined Nov 30, 2010
18,167
Yes. I think you are right. They are not very expensive compared to the time it would require to repair them, and you might even find a repacement on another piece of equipment. I keep a junk pile just to steal parts from old machines, but I occasionally have to place an order for new parts. I needed a 120 Vac fan that was very quiet (for a music amplifier) and I had to pay for a new one. I think this is what will happen to you.
 
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