US Stove 5500M auger motor buzzing

[mrscientist]

Hi, the auger motor in my 5500M makes a buzzing when the auger moves. The buzz doesn't happen until the stove has been on for about 10 minutes. The buzzing does not occur every time the auger moves, but it does seem to buzz on a regular basis. Sometimes it buzzes for the entire auger turn, sometimes only at the beginning of the turn. I disconnected the motor from the auger, and the motor still makes the buzz occasionally when it turns, so it's not related to the auger. When it's disconnected, the buzz seems to be affected by the angle at which I'm holding the motor. I took apart the motor box.The gears inside look OK, and there is still a lot of grease in there. I didn't see any loose parts or bits in there.

I'd rather not have to spend $170 on a new motor, so if anyone else has any input, I'd appreciate it greatly. TIA!

 

[Arti]

The motor is made up of Laminate strips of metal that are riveted or welded tightly together. Sometimes the laminated part of the motor is a bit loose and this creates an electrical buzz, doesn't hurt anything just annoying.

A piece of bare copper wire wrapped around it will fix this problem. In the picture attached is a transformer but the motor is similar put 1 wrap of wire around one corner of the metal , twist it tight and the buzz will disappear. They call it a band in the picture.

 

[mrscientist]

Thanks @Arti! I'll give this a try.

 

[mrscientist]

Hi @Arti, I finally got around to taking apart my stove again and am confused as to where you suggest I wrap the copper wire. Would you please be able to note it on one of my pictures of the motor? Thank you.

 

[HD41]

Some of my auger motors got noisy and locked up. I revived the original factory motor using WD-40 on the motor bushings. I bought two new surplus motors and found they wouldn't turn when received; I suspect they were dropped. I realigned both and they worked. One of the surplus motors locked up again and was realigned a couple of times but it finally gave out after 2 years. I put the second surplus motor on, it's still running after three years. Kind of a trial and error thing to get the armature centered in the field. The original factory motors are still in working condition, one is on the feed auger and the other is a spare.

 

[Arti]

Just around one corner like I show with the red line. Any corner will work Just Twist the ends of the wire together to get it snug on the metal plates.

 

[mrscientist]

@Arti, thanks for the picture, I'll give that a try. But I looked at it a little more and it seems like the sound is resulting from a physical interaction, not an electrical interaction. I detached the motor unit from the upper unit with the shaft. I then hooked just the motor unit up to my stove. If I held the motor upside down, it seemed like the sound would disappear. It seems the sound is coming from the rotor rubbing against the inside of the housing. Is that possible? If so, @HD41, is that where you shot some WD-40, between the rotor and the housing?

In any case, I found some sources besides US Stove from which to purchase the motor, so I'm going to get another one anyway. Thanks again and happy Thanksgiving!

 

[HD41]

Seems the oilite bronze bushings run out of oil and carbon up after a while. I take the bearing cap off and remove the armature (may have shims that will have to be reinstalled) and lube with WD-40 to free up the bushing in the end cap. Loosen the field screws and adjust for a uniform air gap between the armature and field when you reassemble; I just snug the field screws first, hook up a patch cord and if necessary tap on it until it is quiet. Let the motor run on the bench for a half hour or so.

I see you found lower price auger motors, be a good idea to have a spare.

Good luck; Some art, Some science.