Motor fix for Craftsman shop vac


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Old 05-27-18, 09:55 AM
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Motor fix for Craftsman shop vac

Hi,

My 12 gallon XSP craftsman shop vac had developed a very loud high pitched sound. I took the unit apart in stages looking for obstructions, bent fan blades, etc. I finally got down to what was causing it. There are 2 spots on the motor that are ground down. I can only guess that something made its way into the motor to cause this. Unfortunately it seems that the motor itself is not available as a part, I would need to purchase the entire motor housing which would would be more than the cost of a new shop vac. Is there anything I can do here? A thought I had would be to maybe fill those spots in with jb weld or something and make sure it is filed down smoothly to cut down on the noise. Figure if it doesn't work then no real loss. Any thoughts, suggestions?

Thanks,

Mark
 
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Old 05-27-18, 05:12 PM
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That doesn't look like a wear pattern. It looks like that was done at the factory for balancing. Notice how the machining marks in the divot are perpendicular to the rotation of the motor and how there is a definite beginning and end with sharp edges. It was machined into the rotor/armature.

How do the motor's bearings feel?

How do the brushes look? They appear long enough in your photo but do they slide back and forth easily in their holder?
 
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Old 05-27-18, 07:36 PM
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Those indentations are there for balancing.

The commutator could use a cutting. An easy job for a motor shop if you have one nearby. Otherwise you could clean it with some fine emery paper. It needs to be sanded carefully so as not to add any grooves. The gap between the bars needs to be clean too.

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Old 06-03-18, 10:29 AM
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Hi,

Thanks for the heads up about the machining marks. They did seem awfully clean in how it was worn/cut. The brushes slide fine and the bearings seem ok. The vacuum was not used that much before the issue with the noise. Pete, is the commutator needing cutting/cleaning a reason it would produce such a horrendous noise? The gap between the bars seems to be pretty clean already.

thanks,

Mark
 
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Old 06-03-18, 10:39 AM
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Excessively arcing brushes can make quite a racket.
 
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Old 06-11-18, 06:08 PM
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Hey guys,

So I took a crack at your advice and tried to clean up the commutator with emery paper. I went and cleaned it up as you can see in the first pic. It started sparking again and squalling again so I opened it back up and saw what you see in the second pic. I think the brush is somehow marking up the commutator. Cleaned it up again and here is a video (Sound is so loud the phone camera mic is distorting the sound. It is much louder and higher pitched than what you hear). https://www.youtube.com/watch?v=uUHU1LR9-f8

Thanks for your advice!
 
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Old 06-12-18, 04:40 AM
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Make sure the brushes can move freely in their holder. Sometimes dust and debris can make them stick. I've also wrapped fine sand paper around the commutator then rub the brushes over it to freshen their face and make sure their radius matches the commutator's.
 
 

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