fan repair and diagnosis

[RolfeEP]

Hi I have an issue with my fan.
It does not want to spin.
When this problem started, the fan would slow down and make noises like it was jammed or something rather than just spin freely. Now what happens is the fan does not spin at all when I turn it on. Further, I can smell something burning coming from inside the motor. This happens after about 20 minutes of leaving it on while the blades do not spin.

So I have taken out my screwdriver and disassembled my fan. I've looked at other fan repair tutorials on youtube, but the models used are different from the one I am using, so I'm not exactly sure what to do. at this point. What would you say is going wrong with that fan and what do I need to do to get it running smoothly again?

 

[Harald Kapp]

the fan would slow down and make noises

Probably a mechanical failure.

This happens after about 20 minutes of leaving it on while the blades do not spin.

Without the blades spinning, the motor will draw excessive current. Chnaces are that it has burnded out beyond repair.
If you want to try repair anyway, open the motor as much as possible (make notes where all teh screws etc. go). move the rotor by hand and try to locate the point(s) where the rotor gets stuck. Remove any obstacles. Add fresh grease. Reassemble the motor.
Befor you plug the fan into mains:

1. check for electrical safety/insulation: There may be no measurable resistance between any of the mains leads and any electrically conductive part that can be touched.
2. check for mechanical correctness: turn the axle and/blades manually. This should be easy without much resistance. If you feel the motor gets stuck, repeat the cleaning procedure.
3. check for electrical safety/insulation: There may be no measurable resistance between any of the mains leads and any electrically conductive part that can be touched.

If either of these entries in the above list fails, discard the fan. Do not connect it to mains.

 

[dorke]

From your description ,
In my experience the problem is the motors axle gets stuck from
dirt,dust,rust and/or dried out lubricant near the bearings.
You can verify that by trying to rotate it by hand-it should spin freely and effortless.

Try this without opening the motor("fast an easy fix"):
If indeed the axle is stuck ,
you can lubricate with machine-oil(or better engine oil) to the axle.
let the oil go in while manually rotating the axle,
if possible do that from both sides of the axle
till it gets totally free.
If you can't get it to move freely you have to open the motor.

Now,connect the fan to power,
if it spins(possibly with a little help push) there is hope,
otherwise to the garbage bin.

 

[RolfeEP]

Thanks for the feedback.
The fan is indeed dusty. The protection is dusty, the blades and the motor are dusty. When I opened the motor up, part of it, There wasn't just dust, there was grime.

But here's a question. You guys talked about lubricating the axle. I can use machine oil or engine oil.... How would I know if I'm not setting up a possible fire hazard in doing so? I've never tried this before.

 

[Martaine2005]

No fire hazard with lubricating oils. That's what they are designed for! stopping friction.
Has the fan got a bearing or two? That would normally be the case for running first and slowing as it heats up due to friction.
If they are sealed bearing/s, better to replace them. If not sealed, you can clean the balls and housing and re-grease.

Martin

 

[Minder]

Those fan motors are typically shading ring type and do not take lightly to any sort of friction, if the bearings are the sintered bronze type they are porous and if not excessively worn, can be washed with a detergent such as Paraffin (kerosene).
And then soaked over night in light oil.
M.