"Han" wrote in message ...

I posted a picture of the squirrelcage motor in my homemade "air filtration
system" with 18x24" filters. The motor has started to make a high pitched
squeeking noise, and the center circular pieces in the picture (bearings?)
are getting hot. Is there any way to lubricate, or salvage the motor, or
do I need to get a new (used?) motor? This thing has had many, many hours
on it, since I use it too to circulate the air in the basement. So I owe
it gratitude, but can afford another motor. OTOH, if it can be saved
somehow, that would be good. But I don't want it to catch fire!!!

Any advice is appreciated!

--
Han,

I've never seen a bad bearing in these small motors cause a fire, but I
suppose it is possible. The usual risk from hot bearings is thermal
breakdown of insulators within the motor windings and wires, possible
causing a electrical hazard.

If the bearings races or ball are pitted (not that you can see them without
destroying the the bearing set), replacing the bearings is a very good
solution for that type of motor. They will be ball bearing sets, not
sleeve bearings. When you get the replacements try to get the "ZZ" type
which have both sides sealed, as your device is apparently used in a dusty
environment.

Sometimes you get lucky and the bearings stay on the rotor which makes them
easier to remove using a bearing puller. A bearing press is handy for
reinstallation but I've also used a heavy drill press (off) with makeshift
jig. Brinelling is a risk when approaching these with a hammer, especially
if the fit is tight.

Light machine oil was suggested for a temporary fix, and it indeed can
prolong the life of the bearings considerably if they've simply dried out,
if you can get the oil into the bearing set casing. However, there is a
popular canned spray that should be avoided, marketed as a "lubricant" and
is often touted as the fix-all for everything. However, around sealed,
greased bearings, the stuff is a nightmare since it is a powerful degreaser,
which liquifies the packed grease. It's name begins with WD - don't fall for
the hype.

Check for loose mounting as suggested since the cage is fairly lightweight
and would squeak if given the chance.

(The opinions and suggestion expressed above are my own and do not reflect
current enginieering or electrical standards in any way.)
Scott in Dunedin, FL