Noise might be the rotor rubbing against the field iron. Try the fan upside down and see if it returns when warm if ya can. I have turned some furnace fan motors 180 degrees and most lasted another 5 years.
Recommended Oil for Small Fan Bushings?
- Thread starter nielkfj
- Start date
That was a good suggestion. I turned it 180 degrees in the window and ran it for a couple hours on high speed. It didn't make the screeching sound. However, it still made the faint high-frequencing sound. So I am still concerned that the oil is too light and am planning to try a heavier oil, probably the Super-Lube with PTFE.
What's odd is that it is the NDE bushing that has the problem, even though it has minimal radial load on it because the weight of the blade and rotor are basically balanced across the DE bushing. However the NDE bushing supports a thrust load created by the fan. I'm thinking the NDE bushing wasn't oiled properly at the factory. The DE bushing was still well oiled when I first took it apart.
I've had 12v and 24v computer fans run on a PWM speed controller make whining noises at reduced speeds.
It was only 13 khz PWM though, 21K and above and only fido or mittens can hear it.
One can also use some clear nail polish on the windings to stop the whining.
I use voltage buckers for speed control now, 150khz. No whining.
I've pulled the ball bearings from failed fans, and regreased them, and redeployed them on 'other'
It was only 13 khz PWM though, 21K and above and only fido or mittens can hear it.
One can also use some clear nail polish on the windings to stop the whining.
I use voltage buckers for speed control now, 150khz. No whining.
I've pulled the ball bearings from failed fans, and regreased them, and redeployed them on 'other'
Attachments
For electric motor use oil intended for purpose. Available from motor shops, HVAC supply shops, Amazon.
link below
link below
That's what I have been using for a couple of years . I've seen it at some hardware stores . Excellent stuff .
I've had no problems using regular detergent motor oil for motor bushings, for decades. Tools, fans, whatever. 5W-20, 5W-30 before that.
The main thing is, either relube before it runs dry and starts chewing up the bushing, -OR- once you're hearing noise, you need something more viscous, how viscous depending on how bad the wear, or else the shaft wobbles too much and pumps the lube out. However if I had to go higher than 80wt gear oil, it would be short term till I replaced the motor or whole widget. This is almost exclusively a case where someone abandoned something, I've never let a motor chew itself up that bad in my presence.
On the other hand, I wonder if this is a trust washer issue. Maybe there was one and it disintegrated?
The main thing is, either relube before it runs dry and starts chewing up the bushing, -OR- once you're hearing noise, you need something more viscous, how viscous depending on how bad the wear, or else the shaft wobbles too much and pumps the lube out. However if I had to go higher than 80wt gear oil, it would be short term till I replaced the motor or whole widget. This is almost exclusively a case where someone abandoned something, I've never let a motor chew itself up that bad in my presence.
On the other hand, I wonder if this is a trust washer issue. Maybe there was one and it disintegrated?