I bought a new top-of-line Fantastic Fan a couple of weeks ago via Amazon, to swap out the lesser model in our bedroom and put that one into the bathroom (it had a real piece of junk). I had years ago put the previous top-line model (6500?) in our older RV and absolutely loved it and raved about it to everyone.
I was a bit upset when this new one arrived and wasn't as pictured on the seller's add on Amazon (they showed the old one with a different motor). Being wary, I tested it before installation but it seemed just fine so I decided to give it a shot.
30 min after installation, it started a slight squeak at low speeds. Unfortunately that would be a problem because my wife is extremely sensitive to high frequency squeaks/squeals. I let it run intermittently for a couple of days and it increased to a squeal at pretty much any speed. Atwood's warranty policy of requiring it go to a dealer for assessment and then return for later repair was not going to work for us at all. So I forked out $ for a new replacement motor.
In the meantime, being equipped with relentlessly curiousity and a belief that I can fix darned near anything ever made by another human being, I decided to pull that squeaky fan motor last night and open it up (what the hey, I was voiding the warranty anyway by replacing the entire motor myself...) After removing the motor, it squeaked very audibly even when turning it slowly by hand.
Opening it up, I discovered some very interesting things.
First, the bearings used both top and bottom in these 8017A motors are extremely common - over the past 10 years I've seen them and replaced them in roller blades, skate boards, a 3D printer, and a stair-climber exercise machine. Remember the fidget spinner craze last year? Most of them also had the same sealed bearings. In the case of these ones, the bearings were smooth as silk and firmly attached to the commutator shaft and so definitely not responsible. I've seen plenty of bad examples of these bearings, but these ones were just fine.
The motor design is actually fairly ingenious and should be pretty reliable and durable. There really was nothing else I could find that could have been rubbing or binding to produce any such noise. Except for the brushes
The only thing I thought odd about the build quality of the motor internals is that the brushes seemed awfully loose inside the brush guides, more so than any motor I've ever seen (and I've repaired dozens over the years and torn apart dozens more out of curiousity...) From my experience I was highly confident squeezing in the brass guides a tiny bit to tighten them up slightly (still leaving them quite sliding very freely but no longer super-wobbly). Honestly, the brush guides stood out as being the one thing in the entire motor that looked out of place quality-wise, in that everything else looked pretty well designed and built to a reasonably high tolerance.
The other thing I noticed while handing the disassembled motor is that if I tapped the housing with anything, the sound it made had overtones at very similar frequencies to the squealing I had been hearing. I've also been an audio nut for decades and used to pay a lot of attention to resonances of speaker enclosures and all kinds of other things... Definitely found this interesting.
I then googled, and sure enough there are plenty of studies on the causes of squealing brushes in motors. So without any further modifications or lubrication (other than blowing out any loose dust) I reassembled and there was no longer any squeaking when turning by hand or running at any speed. I've now reassembled the entire thing and left it running - quietly so far, fingers crossed.
I may find over time that this fix was not permanent, but at this point my belief is that the squeaking/squealing was a result of 2 things: primary is a high frequency vibration of the motor brushes due in part to the brush guides being far too loose, and secondary is that the motor housing just happens to be of a shape, material and thickness to not do a good job of suppressing (and perhaps even amplify) the noise generated from the motor brushes.
I expect to be running the fan a fair bit over the next 10 days while we prepare for a trip, and then a lot over the following 3 weeks. I will try to remember to update on whether or not this fix holds up.
Fantastic fan making squeaking noise
Linear Mode
