stuck bathroom fan

[DeanR]

Seems the actual fan (you can see the fins in the picture) is gunked up. I thought the motor was shot, it would just hum. Turns out if I manually rotate those fins a few times, the fan frees up enough for the motor to turn it.
But an hour later it's again stiffened up and the motor only hums.
Can't remove that cage to access anything for a cleaning and lubrication and I suspect that somehow getting at it from above would only reveal it to be boxed in up there.
Any suggestions?

[DeanR]

Just got the assembly removed...now I can work on it. I had not noticed the two tabs that hold it in place.

[XJOK2PLAY]

Sorry, it double posted. Please read my next post! Thanks!

[XJOK2PLAY]

Hi Dean.
Yes, I see those in that condition a lot.
They're placed in an environment that gets pretty dirty, and most have "sealed" (re; oxymoron...) type bearings or just brass bushings. They get pretty gunked up, and sometimes it all depends on how long and how many times there's been attempts to run the fan with the stuck shaft as to whether or not it can just be cleaned and lubed and work. If too many attempts have been made to run it that way, it usually burns out the brushes.
Then, the next thing is... how old is it? Can you still buy a replacement fan motor, or the insert assembly? Or has the company quit making them or changed designs?

Broan's a brand that has stuck with the same design motor for more than 20 years, and is pretty common. Those, I can usually rebuild or replace.
Not sure about your brand. Might score one on Ebay if yours is toast?

Sometimes though, all they need is a good cleaning and some WD-40.

Having to change the complete can out's what's a drag... and a mess.
But, like they tell me... if everyone could/would do it, I'd be out of a job, I guess! Lol.

Good luck with it, Dean.

[DeanR]

Here's another picture Bob. Took out the set screw to the shaft but the fan does not want to slip off.
Also noticed a peach colored chalk-like material kind of caked on the blades (removed with a toothbrush). What the heck might that be? Very clean otherwise (no visible gunkiness).

Motor/fan (out of it's housing) spins right up when I plug it in, on the table. Smooth and quiet. Still needs a nudge to get going if it's been sitting a while. Would I still need to do any work on the motor?

What prevents it from spinning up?

I have used it very rarely, which I suspect is the basis of the problem.

motor - broan 99080096 - $62.86 at Amazon

Hi Dean.
Yes, I see those in that condition a lot.

[TopCatGr58]

Hey Dean,

That looks like an aluminum cage fan blade....it probably wasn't ANODIZED, but raw aluminum forms a protective oxide just exposed to air, but the pores are still open, and then in the HUMIDITY environment of the bathroom, heat, etc., it was probably a combination of corrosion and either mold, or just really aged dust... being in the medical field, you know that dust is like 90% cast off human skin cells!

As for the motor....I don't know much about working on them aside from that as Bob stated, the brushes can get worn or burned....they might also be slightly corroded due to the same environmental environment.... not sure if it would be safe to use something like DEOXIT spray down in it's innards in an attempt to remove some corrosion/varnish which might help the motor activate better/quicker with less current so that it could spin up WITHOUT a nudge?

As stated, it looks like it does have sealed bearings, at least the end bearing shown isn't OPEN, so it's hard to say if you would be able to take that casing cover off and get access to the bearing/shaft for both cleaning and relubricating??

T.C.

[XJOK2PLAY]

Dean,
I concur with TC about the pink stuff on the cage.

There's probably 2 or 3 things that could be causing the motor to sometimes require help to spin up... brushes bad, or it may have burned a wire into somewhere on the armature, so the armature's now weak, or a flat spot on the armature has occurred.

Regardless, the motor's probably had it, and you'll have to replace it.

Question: is this a vent only, vent/light, or heat/vent/light?
I ask, because it looked like 3 plugs/outlets in your pic.
(I've also seen some models that have 2 lights/ plugs and 1 for vent.)

If it's a vent/light unit, $65 is about what a new Broan unit costs.
But, it's a lot more labor to replace the entire thing, compared to just swapping a motor out...

If it were me, I'd probably get the Ebay motor, provided the rest of the unit's good.

[crazy steve]

I've disassembled and cleaned/relubed these, it doesn't always work but may be worth a try. You'll have to get the fan cage off the shaft though.

Synthetic motor oil works well as replacement oil; any 5W or 10W will work.

[ViperRon]

They generally have different levels of these fan motor assembly and two measurements for them one is sone's and other cfm. The low cfm motors tend to be weak and most times high sone which is sound partly caused by bearing assembly and partly because of the assembly it is mounted too. The bearing assembly on the cheaper can be oiled but if much damage has occurred then it probably has burnt the armature or brush assembly, These can be taken apart but often the assembly is designed for machine assembly and very hard to pull apart and often you damage it. The brush can often be polished with some sand paper and the armature can be cleaned up with a brass wire brush but if severely scratched it will soon wear the brush again. The problem that usually causes the slow no start is brush dust in the armature recesses. The better way is to get electrical contact cleaner from an auto store and use the little stem to blast out the brush armature assembly while spinning. A good practice is to get some thick foam like used to weather strip and cut a couple of 2 inch pieces and adhere them to the assembly when putting it back in to absorb noise. If the slightest pressure is put on some of these fan cages they will bend and cause a lot of vibration creating noise. Often I find these things are not worth the trouble unless someone has installed an off brand model so different in size that a direct install replacement can not be found. If in a custom plastered ceiling putting in a new one where you have to cut can become a real problem. I have just cut the motor mount out with a dremel and pop riveted in the new fan assembly and cage that works pretty good

Often I find that it takes at least an hour to take one down clean and check it and about 3 to disassemble one which makes is not worth the money and aggravation just to clean them out as 3 to 4 days later its back to being a problem.

[DAVINCI]

AC motors don't have brushes

[CaptonZap]

Here's another picture Bob. Took out the set screw to the shaft but the fan does not want to slip off.
Also noticed a peach colored chalk-like material kind of caked on the blades (removed with a toothbrush). What the heck might that be? Very clean otherwise (no visible gunkiness).

Motor/fan (out of it's housing) spins right up when I plug it in, on the table. Smooth and quiet. Still needs a nudge to get going if it's been sitting a while. Would I still need to do any work on the motor?

What prevents it from spinning up?

I have used it very rarely, which I suspect is the basis of the problem.

motor - broan 99080096 - $62.86 at Amazon

Do you see that little hole at the rim of the back plate, the one at the center of the label? That is an oil hole. If you look closely, you will see one on the other end as well. Place the holes up, and put some thin oil in each hole, and let it set for a few hours. Refill as needed. The oil will saturate a felt that surrounds the sintered bronze bushing bearings and that is what keeps them lubricated. If you take the blower wheel off and get to the shaft, try working some Kroil or equal into that bearing, as it is usually the one that dries out. Once you get some lube on the shaft, turn the motor shaft up and run it, shaking the motor up and down at the same time. There should be a little end play in the armature, and that will help work the Kroil into the bearing.
As Davinci noted, that is an AC motor, and only has one moving part, the armature.
Re install the blower wheel, and you're good to go.

[DeanR]

Thanks for all the responses guys. Still can't get the fan cage to come off the shaft.

I'll oil those two holes CZ. Have to go out and get something light. Would some PB Blaster that I have be of any benefit?

It's a fan, light and nightlight. No heat.

[CaptonZap]

Thanks for all the responses guys. Still can't get the fan cage to come off the shaft.

I'll oil those two holes CZ. Have to go out and get something light. Would some PB Blaster that I have be of any benefit?

I'm not to thrilled with PB Blaster as a lubricant, but if you wife or other girlfriend has any sewing machine oil, that would be ideal.
If you are clever, you could run a drop or two of oil in a swizzle stick, or the plastic snout of the PB Blaster, and use gravity to drop some oil where the shaft comes out of the end housing. Messy, but might get enough on the shaft to work into the bearing. Or let it sit for a few days and let the oil seep into the bearing from the felt wick.
Some of those fan scrolls have a spring clip that holds them on the shaft, and pushing down along both sides of the motor with some chop sticks might get it to come off. You will have to be the judge of the condition of the plastic, and how much evenly applied pressure to apply. DO NOT APPLY PRESSURE TO ONLY ONE SIDE. Broan will have replacement scrolls for most of their fans, so if you are stronger than you think, or the plastic is weaker than that, you will still be able to salvage the whole thing. Google is your friend.

CZ

[ViperRon]

That specific motor is an induction motor and yes does not use brushes. It depends on the armature and stator windings to control spin using Faraday's Law: Curl of E = - dB/dt you can get one of the other experts that corrected me to explain that curl of E thingy. The bearings are the only part you can do anything with. If they are worn to where the shaft slides to one side in the slightest or has been put in a bind and heated up damaging the windings it will have intermittent start issues period. There is very little that can be done to fix induction motors other than replace the thermal fuse if it has burnt out or replace the bearings usually machine pressed. If you really want that looks to be aluminum squirrel cage off and it did not have a another set screw or the clips CaptonZap mentioned to grip the shaft. Get a torch and heat the center of the cage mount with circular motion to evenly and quickly spread the heat and if you are lucky it will expand enough to slip off the shaft ridges. How ever if the motor spins free and has still has start issues you are done fixing that AC brushless motor.

[CaptonZap]

Good eyes, Ron.
Getting behind my bi-focals, and close to the screen, it is indeed a metal fan. Which changes the method of attachment from that of plastic, as you noted.


Same song, diffrent key, so to speak.

CZ