Any centrifugal fan that is secured to the fan motor shaft with only
one bolt will eventually become loose and begin to hit the fan cage.
This is especially so for fans that are heavy and operated
horizontally. A fan that is hitting its cage will cause the
temperature cut-out to trip and will eventually burn-out. These types
of fans are usually found in furnaces. It may be possible to avoid
this by drilling and tapping a second hole perpendicular to the first
one on the fan for another bolt to better secure it to the motor shaft
or check to make sure your fan is not secured by only one bolt before
On Mon, 03 Jan 2011 20:47:48 -0800, Molly Brown wrote:
Surely any fan with just one bolt will have the threads cut in the
opposite direction to the motor's rotation, so that the motor's turning
will have a tendency to tighten the bolt rather than loosen it? Or have
you seen designs where this isn't the case?
On Tue, 04 Jan 2011 09:24:57 -0500, Stormin Mormon wrote:
Yep, I'd expect some kind of thread sealer in conjunction with properly
torquing down the bolt would do the job - unless the fan was allowed to
get so choked with crap over time that vibration became significant (but
that's what periodic maintenance is for, right? :-)
(re. your other comment about a hose - you're lucky, my outside faucets
are about 3' beneath the snow and will be for another few months :-)
I recently took the squirrel cage from a centrifugal blower off of the motor
shaft (it was from an ancient oil burning furnace). It was attached with
*one* set screw, and came off without too much trouble, despite having set
out in the rain for a number of years. There was no evidence on the shaft
of having ever slipped over the years (mind you, this was a 1/8HP motor,
albeit a fairly large 1/8HP motor).
It depends on whether the securing bolt/machine screw comes in from
the side or whether the fan is held on by a nut on the end of the
motor shaft itself. You don't say which you mean so the premise is
faulty, as in FAWLTY TOWERS.
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