"David Nebenzahl" wrote in message
s.com...
On 9/5/2008 4:03 AM Rheilly Phoull spake thus:

Mikepier wrote:

On Sep 5, 4:10 am, Rheilly Phoull wrote:

Bob F wrote:

I've seen a number of older exhaust fans that start very slowly. Turn them
on,
they barely turn for up to several minutes, then finally speed up fairly
quickly
to normal operating speed. Can anyone suggest why this happens, and a way
to fix
them to operate properly?

First thing to try is lubing the bearings I would think

If you are talking about the roof attic fans, the motor might be
starting to go. They sell replacement motors at Lowes or HD and they
are easy to change.

Sure, that will fix it but having spent a large part of my work life sorting
that sorta stuff I can tell you a lot of the time the motor runs away with no
attention until it stops or exhibits the symptoms described.
The manufacturers provide ports to apply periodic lubrication which are by
and large ignored by the average punter. A slow start is almost certain to be
an underlubricated bearing or one that has been worn out by long usage or
underlubrication, usually both.
Nowadays the cost of professional maintenance can exceed the cost of a
replacement (assuming you DIY) so there ya go. For me there is nothing to
lose with trying a squirt of light oil on the bearings before spending ya
moola :-)

True that.

To which I would add two things: 1) Most motors will last forever if
maintained. They rarely "burn out", but simply get gunked-up bearings.

2) If squirting some oil into the bearing cups doesn't do the trick, then it's
time to take the motor apart, clean and lube everything, and put it back
together. Helped a friend do that to an exhaust-fan motor that was thickly
coated with cooking grease and just sat there and hummed. We knocked it apart
(had to use a cold chisel around the cover seam), whereupon one of the
armature wires broke off. No problemo: a little soldering-iron action plus
some heat-shrink insulation fixed that. Soaked the bearings in paint thinner,
cleaned them, lubed and put together. Now it works like new.


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I seem to have another project to do. Thanks everyone for the feedback.