(ET) Motor apart, still binding.

[Chris Zach <czach computer org>]

Ok, this is odd. I take the mower motor apart.

The shaft and armature looks to be straight. No big issues there.

I can't see any shorts in the armature. Trying to measure resistance 
with a digial vom is pretty much useless, so I hooked a power supply to 
the brushes, put the armature in the top cap (so it was contacting the 
brushes) and set the current in the taken apart motor to 1 amp. Then 
watched as I turned it around.

The meter would fluctuate between .6 and 1.4 amp draw, but did not go 
off the scale. Thus I don't think any of the windings are dead shorted.

Spun the shaft with either end (bearing) in the vise. No wobble I could 
see when hand-spinning it.

Both bearings seem to spin free, with no detectable slop. Just for 
laughs I cleaned out the bearings and re-applied grease and a drop of 
oil. Nice and quiet.

Looked at the magnet housing. Looks fine in there. Appears to be four 
magnets, arranged 2 over 2. Doesn't seem like it would interfere, no 
signs of cracking. A quick test with a long screwdriver shows magnetic 
activity on all four of them.

Re-assembled. The motor still feels like it's binding and goes "chug 
chug" and draws insane current. More like there are certain places it 
"wants" to be, and certain places it does *not* want to be. Sanded the 
armature to remove any traces of rust. No problems there.

Any idea what is wrong with this motor? I'd send it to bill, but :-) 
Next step might be to paint the magnets and see if there is any 
interference...

Chris