"Evan" wrote in message
...
On Sep 2, 9:48 pm, "hr(bob) "
wrote:
On Sep 2, 3:55 pm, Evan wrote:



On Sep 2, 2:59 pm, bob wrote:

I bought a high velocity floor fan with metal blades (model 9220). On
the
fastest setting, the fan vibrates slightly, but it has rubber bushing
between
the fan and the feet, so the vibration is isolated.

However if I wedge the fan in a window to use as an exhaust fan, the
whole house
starts to rumble since the fan cage is touching the window frame.

Is it common for this type of fan to vibrate due to off balanced
blades? I don't
see any counter balancing weights on the fan blades. I imagine they
would look
like those on a car wheel. I also don't see any holes drilled on the
blades
(another way to balance)

Is there a kit for balancing fan blades?

If fans blades are not balanced, I wonder about 40 inch fans or large.
Wouldn't


Fans need to be dynamically balanced as well as statically.
Putting pennies on a blade may statically balance a fan but not dynamically.

Think of it as one of the blades has slightly more"twist" than the others
and there may be your (dynamic) unbalance problem.