Another odd one - MinkaAire 84" DC fan horrific grinding noise during failure to accelerate from Speed 1

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ForumUser1

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Hi Fellows!

So, another failure of electronics/motor … I gave up on trying to repair this a couple of years ago.

I have a five year old six speed DC powered ceiling fan made by Minka Wire - 84”. It has, from the beginning been a real PITA.

Initially, I noted - the RPM speeds were off - Speed 1 was far too fast, and then Speeds 2-4 were about the same, and 5-6 about the same. So, I put a piece of tape on one of the blades and counted RPMs for each speed. A factory rep provided the data sheet on RPM by speed. Waaaay off. On the advice of this same rep, I replaced the receiver/controller board - fixed it - dead on speeds.

Fast forward about 18 months - when selecting a higher speed, the fan made a horrific grinding noise. If I turned the fan off, it would sometimes require help getting to Speed 1 - ie, I used a fishing rod to spin it (it’s about 10’ off the floor) and it would then stabilize on Speed 1. If I selected Speed 2 it would usually start the grinding, again, but sometimes would go to Speed 2.

Talked with the same rep - he said, “replace the controller, again. So, I did this, but it didn’t do anything. Checked in again with the rep - he said, “You need to buy a new fan.” I asked for diagrams/schematics of construction. He said, “No one has those - you need to buy a new fan.” Figure about $750. Since it still works on Speed 1 (in either direction), I just accepted the performance would always be Speed 1.

Here’s a thread I started on doityourself.com in 2022 - never resolved so I just accepted performance on Speed 1.

https://www.doityourself.com/forum/...red-ceiling-fan-clunking-random-behavior.html

Is it possible the permanent magnets/or the assembly holding them have come loose?

Here's mine -

And, another MinkaAire different model, same sound-

Thanks!
 
ZZO,

What would you do ... is there a way to leave it in place (it's on a 14' ceiling) - drill and tap some screws in the casing? A schematic or photo of the inside would help me guess where to place the screws

Have seen videos of Indian fellows rebuilding DC motors and housings sort of like this - and, in many cases is a loose magnet, or ring holding the magnets.

Here's a shot of the motor housing ... I had a short video of it, as well - can't post, but it sounds like "thunk-thunk-thunk-thunk-etc" hard metallic and with an echo.
 

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Check tightness of all bolts and screws on the motor housing.
Check whether their is any chance of the motor housing
1) Does it click when you reverse the direction of the fan (assuming your fan is reversible)?
2) does it make noise at low and high speeds - is the thump faster at high speeds or the same?
3) does it make noise with all the blades off? (On low and high speeds?)
 
in video text , the guy says ,
screw a very tiny screw thru the
housing into the magnets on each side to hold it in place.
Now it works beautiful again. Not sure
why the manufacturer thought glue was a good idea
 
Tony Stewart said:
in video text , the guy says ,
screw a very tiny screw thru the
housing into the magnets on each side to hold it in place.
Now it works beautiful again. Not sure
why the manufacturer thought glue was a good ideal
Click to expand...

There is some risk in this maneuver - the mechanical risks of metal chips from drilling getting caught in the bearings can be ignored because the thing is essentially junk already and not covered by mfg warranty. The electrical risk is slight but I don't know what the internals look like in case a metal turning from the drilling makes an electrical short (hot to ground).

Also, drilling into a magnet and getting a screw to tap into the magnet is questionable and depends highly on the type of magnet used.

Good luck.
 
Yeah, I recognize the risks ... big question is WHERE to place the screws. The magnets are in a plastic ring which is glued to the housing, or are they individually glued?

The behavior is as follows:
- fan off and not moving
- select Speed 1 ... DC twitches occur and it may or may not start turning
- if it doesn't spin up, then assist in spin and it will stabilize on Speed 1 nice and quiet
- selecting any speed while stable in Speed 1 results in a cacophony of noise
NOTE - on occasion, I was able to select Speed 2 from Speed 1 and it who make noise then make it to Speed 2, but this was rare
 
When it's making noise, what happens when you switch it off?

○ Noise stops the instant the power is cut, and the fan coasts down quietly. (This was what the fan in the video did.)

○ Noise continues after power is cut and the fan coasts down.

○ Fan stops turning nearly instantly when the power is cut.

The fan in the video is unusual. It sounds like something is impacting when it's turning, but the noise stops the instant power is cut. Usually, impacting would continue as the fan coasts down.

Can you record the fan from turn on to noisy (get at least 10 seconds at the noisy speed), and continue recording when you cut the power until the fan stops turning? From the time the noise starts until the fan stops turning, please don't talk – I want to hear clearly what the fan is doing. (Career machinery vibration analysis here – clearly hearing the noise the fan makes could be very diagnostic as to the cause of the noise.)
 
When the fan is switched off, it coasts down without noise.

The noise heard in the video is when the fan is selected from Speed 1 to another speed ... while there is some difference in fan blade speed, the fan never gets to the speed selected, it just continues to make more and more noise.
 
I am a little hesitant to turn it off - but, will try and get what you are asking for ... but, to the electrical nature of the issue, wouldn't turning off the power unpowered the motor - ie it should just coast down - as it does.
 
 
That's very strange, and it does sound like a box of rocks!

I can't quite process if the noise is synchronized with the rotation rate at high speed.

Definitely impacting going on so something is loose. It might be loose magnets as you suspect. But it could also be excess play in the bearings allowing enough movement for the rotor to hit the stator.

I don't think drilling into the case blindly to screw down the magnets is a good idea. Magnets are brittle, so you're more likely to fracture them than to secure them.

I think "open and inspect" is the right answer here to determine if anything is loose or if the bearings are loose in their housing or worn to the point of uselessness.
 
The rotor may also be out of balance, which coupled with sloppy beings could force the stator into the rotor.
 
If bearing it would seem like it should be present, audibly, at all speeds - different, obviously, but still audible?

I agree - but, given the difficulty of getting it off the ceiling box - I'm looking for a way that doesnt require a 20 foot ladder

The inference from one of the guys who commented online seemed to indicate the magnets attach directly to the housing, something like this -
Or, are the magnets embedded in a plastic ring around the perimeter of the housing?
 
Same recommendations still stand. "Open & inspect" will be more effort but stand a much greater probability of ending up with a working fan.
 
glue the magnets with polyurethane (subfloor) adhesive. This is a known issue for this product.
 
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