Steve Barker wrote:
On 1/3/2011 10:47 PM, Molly Brown wrote:
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 buying it.

I've never heard of one coming loose ever. It's usually the opposite,
you can't remove the dam things with a jackhammer.

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).

Jon