Motor stops working when bolted to gearbox casing

[smashweld]

Motor spins fine either direction when out the casing...even works when it's in place with the nuts on loose like in the picture...only stops working when you tighten the 2 nuts holding in place right up, just get sparks at the battery terminals/wires

Any ideas?

 

[Pete.]

Start by cleaning off the corrosion which should only take a few minutes with a wire brush. That will rule out distortion caused by the mating faces bending from trapped oxides. I has a AC induction motor that would lock up when the end bell was tightened. I stripped it down and filed all the mating edges clean to get rid of any burrs. After that it pulled up nicely and spun freely. There wasn't even anything obvious causing it to happen but it did the trick.

 

[Kram]

With the casing done up will it turn by hand? Sounds like it is binding solid. Trying under power for more than seconds, will cook the windings if the rotor is stalled.

Bearings/gear alignment/bent shaft?
Try removing the middle gear.

 

[smashweld]

You're right...with the nuts done up it won't turn by hand with no gears connected!
The gears etc all fine...the full thing works fine when the nuts are on loose ..but obv it moves a bit...

 

[smashweld]

Cleaned it up with a wire brush as suggested...all good now. Can still tighten it so much it stops working but no movement at all when it's working.
Might put some nylocs on it and do them up just enough


Cheers

 

[brightspark]

Cleaned it up with a wire brush as suggested...all good now. Can still tighten it so much it stops working but no movement at all when it's working.
Might put some nylocs on it and do them up just enough


Cheers

shim the faces and slightly open the holes to give adjustment

 

[smashweld]

do you mean just thin piece of metal between the motor + gearbox case??

tried tightening up the nuts on the long bolts that hold the motor casing together - tightening those up more can stop it working too, without involving the gearbox casing...
curiosity got the better of me so took the motor apart...the bearing? the armature shaft goes through at the end of the motor is pretty stiff, not sure what it's meant to be like, will turn easy enough but not spin free if that makes sense
great fun trying to hold the brushes/springs in place to get it back together!

 

[Seadog]

Looking at the rust on the armature and end cap I'd suspect that the bearing is on its way out.

 

[smashweld]

disappointing, it does say 'do not disassemble no serviceable parts inside' on the label on the motor - how true is that?!

 

[brightspark]

disappointing, it does say 'do not disassemble no serviceable parts inside' on the label on the motor - how true is that?!

its ****** if u can buy the brushes and buy the front roller bearing presumably the back one is a bronze bush next to the armature

 

[smashweld]

me not being familiar with the proper names/terms...
i'll take couple more pics tomorrow, I think where the armature/shaft goes in at the back is part of the top cap? that also has the brushes etc attached
the bearing on the end cap doesn't seem/look like a normal roller bearing, it allows movement like on a cv joint/driveshaft/propshaft type movement as well as rotational

 

[500e]

Make sure the rear one pivots freely if it is a spherical bush, deep cage ball bearings also have some latitude to self align.
Clean every thing as mentioned lube the bush / bearings.
Caravan Mover ??

 

[smashweld]

yes...spherical is what I mean for the cv joint type movement...
it's for adjustment on a lightweight scarifier type implement...pretty much an alternative to a manual adjustable tractor top link

 

[smashweld]

this is the 'bearing'...can it be replaced or is it part of the end cap?
used some wd40 and blew it out with the airline a few times, is there something better that would help it? - it's better now but still not as free as I'd expect...although I don't know exactly how it should be tbh

 

[awemawson]

From that angle it looks more like a spherical Oilite sintered bush retained in a sheet metal case to me

 

[smashweld]

nice - just reading https://www.bowman.co.uk/bearings/oilite-bearings-self-lubricating-bearings

I suppose letting it sit in oil would help with the self lubricating ??

 

[awemawson]

I used to leave them in a little pot of hot oil and let them cool over night. But actually most come pre-lubricated so in theory not necessary.

 

[smashweld]

do you think it could be replaced?

take it they're compressed on the shaft bit like an olive? the little metal tabs that keep it centred...will it just pop out from them with enough pressure?

 

[awemawson]

Absolutely - it should remove quite easily if it is indeed a spherical bush.

 

[500e]

Some are held in with a spring steel plate, the one you have looks to be in a frame, pickling with an alloy cleaner to remove Might help it all looks badly corroded.
Don't leave it in the cleaning agent or it could all disappear.
If that works & its loose after cleaning and there is a outer cage Locktite.
Personally I would flush it out 4/5 times with break cleaner moving it around till there was no crud coming out then leave in hot oil as @awemawson suggested.