Question Small Electric Fan Motor

[inmoncolley]

Not sure this is the right forum for this....
My "Ease Home" model TF-20B-L 20" floor fan with a Massey TF-20L motor stopped. Yes, it's an Aldi special, no less! This small fan put out more air volume than my industrial floor fan and a lot quieter. It's the main reason I bother trying to fix it. I've never had a 'cheap' floor fan that put out the air volume this one did. At first I thought it was the capacitor. Further troubleshooting found a well-hidden 2A heat sensor fuse blown. I replaced it. The fan worked but did not have the speed nor volume. So, I replaced the cap with an equivalent 10uf. It worked better than the original but still not 'up to speed' or, volume. After letting it run for 30+ mins, it started slowing down until it almost stopped. I turned it off, waited 5 mins or so and turned it back on. It ran for about 3 mins and started slowing down again. I have not tried another cap.
The motor is clean with no apparent damage to the Stator or Armature. It didn't appear overheated or have a 'burn' smell. It seems as if the cap isn't doing its job. I wanted to get a second opinion before continuing.
Sure would appreciate someone pointing me in the right direction as to what to do next?

 

[kanewolf]

Not sure this is the right forum for this....
My "Ease Home" model TF-20B-L 20" floor fan with a Massey TF-20L motor stopped. Yes, it's an Aldi special, no less! This small fan put out more air volume than my industrial floor fan and a lot quieter. It's the main reason I bother trying to fix it. I've never had a 'cheap' floor fan that put out the air volume this one did. At first I thought it was the capacitor. Further troubleshooting found a well-hidden 2A heat sensor fuse blown. I replaced it. The fan worked but did not have the speed nor volume. So, I replaced the cap with an equivalent 10uf. It worked better than the original but still not 'up to speed' or, volume. After letting it run for 30+ mins, it started slowing down until it almost stopped. I turned it off, waited 5 mins or so and turned it back on. It ran for about 3 mins and started slowing down again. I have not tried another cap.
The motor is clean with no apparent damage to the Stator or Armature. It didn't appear overheated or have a 'burn' smell. It seems as if the cap isn't doing its job. I wanted to get a second opinion before continuing.
Sure would appreciate someone pointing me in the right direction as to what to do next?

I would think it is a bearing/bushing failure. That would cause excess resistance, slowing and overheating.

 

[inmoncolley]

I would think it is a bearing/bushing failure. That would cause excess resistance, slowing and overheating.

Thanks kanewolf. The armature shaft runs through bushings with oil soaked felts which were actually still 'wet' but I saturated them again. It spins smoothly manually, there's no apparent wobble and the motor didn't feel hot just warm as expected. You're probably correct. It's something I will check again. Thanks.

 

[kanewolf]

Thanks kanewolf. The armature shaft runs through bushings with oil soaked felts which were actually still 'wet' but I saturated them again. It spins smoothly manually, there's no apparent wobble and the motor didn't feel hot just warm as expected. You're probably correct. It's something I will check again. Thanks.

Remember there is also a bushing/bearing on the tail of the shaft. If you can see the shaft, a failing bearing/bushing would generally score the shaft.

 

[inmoncolley]

Remember there is also a bushing/bearing on the tail of the shaft. If you can see the shaft, a failing bearing/bushing would generally score the shaft.

Thanks again kanewolf. I'm going to pull it apart, again, to check. Both ends had a tight fit. I didn't notice any burrs but that doesn't mean they aren't there. I'll get back in a couple of days or so as to my 'adventure'. Would 1500+ grit do more harm than good?

 

[kanewolf]

Thanks again kanewolf. I'm going to pull it apart, again, to check. Both ends had a tight fit. I didn't notice any burrs but that doesn't mean they aren't there. I'll get back in a couple of days or so as to my 'adventure'. Would 1500+ grit do more harm than good?

If it was me, I would use a little bit of automotive polishing compound to polish the spindles. You don't want to take off much material.

 

[inmoncolley]

If it was me, I would use a little bit of automotive polishing compound to polish the spindles. You don't want to take off much material.

Got it kanewolf. Thanks and I'll get back as soon as I can.

 

[inmoncolley]

Got it kanewolf. Thanks and I'll get back as soon as I can.

Update: I used auto rubbing compound on both ends of the armature shaft and as best I could on the bushings then coated the shaft and bushings with a thin layer of silicone grease. I ran the fan for about 1.5 hours. While not really up to speed, it didn't slow down although I could hear some 'wow and flutter'. There's a 'hum' on high and a louder, more pronounced hum on low. It sounds like a motor under stress. The new cap helped only slightly. I could touch the motor but one would not want to keep their finger there for long. At this point, the fan is 'ok' for occasional use. It's definitely not 100%. As I tried to impress upon those who were using this fan, it wasn't designed to run 24/7. Bearings over bushings would have prolonged it's life. Thanks again for your help