How to fix unbalanced fan blades on attic fan?

[JEDI]

THread about Replacing my burned out attic fan:
http://forums.anandtech.com/showthread.php?t=2427686

To get out the old motor/blades from within the attic, I had to bend a support arm attached to the housing.
So when I put in the new fan, I unbent the support arm as much as I could.

but the blades got caught on the support arm.
so I pushed the blades a little.

now when It turns on, I could tell from the spin that the blades are not even.

How much will this hurt the motor?
and is there an easy fix?

 

[pcgeek11]

Does it vibrate or is it just not centered in the housing?

If it doesn't vibrate don't worry about it.

 

[cabri]

If it is vibrating; then it will be added wear on the motor bushings and you will need to replace it sooner than the expected lifetime.

 

[JEDI]

Does it vibrate or is it just not centered in the housing?

If it doesn't vibrate don't worry about it.

I cant tell if its vibrating or not.
attic is too hot to get up there now.

but the fan only turns on when it's too hot.

it's quieter than the old fan.
(it was put up ~10yrs ago)

 

[SparkyJJO]

Bending the blades a tad probably won't do much since you didn't change the weight of the blades. The distribution maybe slightly, but if you only tweaked it a bit you're probably just fine. generally if the fan is off balance enough to be a problem it will vibrate/roar pretty noticeably.

 

[Greenman]

I cant tell if its vibrating or not.
attic is too hot to get up there now.

but the fan only turns on when it's too hot.

it's quieter than the old fan.
(it was put up ~10yrs ago)

There should be an adjustable thermostat on the fan, or you could just jump the control circuit.
To balance the blades you'll need to add weight to a blade, trial and error is how you do it. Once you figure out which blade needs weight and where, you'll have to glue it on.

While you're up there you might want to consider putting the fan on an SSU with the smallest fuse you can find in it. I've seen two fires caused by the fan motor rusting over the winter then catching fire the first time they came on. The motor burned before the breaker tripped.

 

[tsiunltdus]

Add a little weight to the blades one at a time to determine which one is unbalanced. Once it is determined then glue the weight onto that blade.