On Mon, 07 Jan 2013 10:56:52 -0500, Jim Elbrecht
wrote:

DerbyDad03 wrote:
-snip-

Wouldn't the fan belt squeak on startup, not shut down?

I'm thinking of the squeal that a loose automobile fan belt makes as a
car accelerates. It doesn't squeal once you reach a steady state speed
or when you take your foot off the gas because it's not going to slip
as it slows down.

Wouldn't the same thing occur in a furnace - slippage on startup but
no more torque (?) once the motor shuts down, therefore no squeal.

You might be right. It has been a long time since I had that squeak.
Jim
On my old belt drive 2 speed furnace fan the belt chirped every time
the fan swirched from high (heat or cool) to low (standby circulation)
and not when starting. The inertia of the spinning fan was higher than
the accereation torque of the motor. Switching to low was like
slamming the brakes.