by Shawn L

Bostitch compressor has hot electrical smell and seems to be excessive arcing?

It’s a 6 gal oil-free Bostitch pancake compressor. About 4 years old, used infrequently.

Bostitch 6 gallon air compressor

Bostitch 6 gallon air compressor



Air issues are fine but recently it’s begun to smell really hot electrically.

I opened the motor cover and powered it on. Seemed there was excessive arcing between the brushes & commutator although I don’t know how much there should be. The commutator was quite dark.

I polished it gently back to bright look and verified all seemed to be fine with the brushes.

Powered it back on and the commutator was quickly darkened and the arcing was the same amount.

Hot electrical smell is reduced but I’ve only had the motor on 20-30 seconds.

Commutator is hot; sizzles when touched with a wet finger.

Would like to get input here first before running long and possibly damaging it?


by: Doug in

Yeah, that ain’t good.

I’d take out the brushes and make sure they move freely in the holder and have a fair amount of spring to them. Also check that they seat onto the armature flat.

Might want to take a meter to ’em to make sure they are electrically solid.

Make sure the windings in the armature are not shorted together – may be copper dust in the commutator.

The commutator should be sort of a dark almond color, not black, and you shouldn’t see but a tiny arc.

Please update us after checking.