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-   -   Identifying proper rotation of squirrel cage wheel (http://www.diychatroom.com/f17/identifying-proper-rotation-squirrel-cage-wheel-182922/)

justplumducky 07-02-2013 11:05 AM

Identifying proper rotation of squirrel cage wheel
 
1 Attachment(s)
After finding a thread in this forum titled: FURNACE NOT BLOWING HARD, which is really good info for newbies like me - see link below (and doing a little unsuccessful googling), please confirm, or not, my conclusion:
The cupped side of the blade pushes the air (at the outside edge of the wheel - see pic below), which creates low pressure inside the wheel, thereby drawing a continuous flow of air into the inner area of the wheel, then to the outer edge where it gets pushed against the inside wall of the housing till it exits the opening in the housing. The cupped side of the blades should be facing toward the direction of rotation.
This is the thread - has lots of info about weak air flow coming from vents: http://www.diychatroom.com/f17/furna...-78074/index4/

yuri 07-02-2013 12:30 PM

it turns clockwise as you look straight at it now. you should also carefully look at a variety of condenser fan blades when they are slowing down after the machine stops to see the shape of the paddles and how they scoop air so later you can tell if you have one running backwards. variety is necessary as they differ.:yes:

biggles 07-02-2013 12:41 PM

see those rounds on the squirrel as they et saturated with dirt and dust they can actually round off and the result is less scooping of the air to throw it up into the duct.with the unit running ac for those reading this ice will start to walk its way out of the air handler trippin to the compressor out side.they won't get rounded if you keep the filters clean having carpet and pets effects them also...

old_squid 07-02-2013 12:47 PM

Your conclusion is correct.

justplumducky 07-02-2013 02:36 PM

Thank you for the confirmation, old_squid.

Quote:

Originally Posted by biggles: see those rounds on the squirrel as they et saturated with dirt and dust they can actually round off and the result is less scooping of the air to throw it up into the duct.with the unit running ac for those reading this ice will start to walk its way out of the air handler trippin to the compressor out side.they won't get rounded if you keep the filters clean having carpet and pets effects them also...
Thx much biggles - I have cleaned a few blower assemblies/wheels, in my limited experience, but never understood exactly how/where the location of the dirt on the blade affected the air flow. And quite possibly relative to another one I'm looking at now, I never realized the blower wheel could be responsible for the icing up at the cooling coil in a packaged unit (A/C only), which I assume is also true. Already cleaned the evap. coil on this one and it's still icing up. I realize it could be low R-22, but the squirrel cage does have a significant layer of dirt - have no doubt it's compromising its performance. :notworthy:

Quote:

Originally Posted by yuri (Post 1210461)
it turns clockwise as you look straight at it now. you should also carefully look at a variety of condenser fan blades when they are slowing down after the machine stops to see the shape of the paddles and how they scoop air so later you can tell if you have one running backwards. variety is necessary as they differ.:yes:

Will do, you bet, thx (always appreciate your tips).

ddawg16 07-02-2013 02:50 PM

Quote:

Originally Posted by yuri (Post 1210461)
it turns clockwise as you look straight at it now. you should also carefully look at a variety of condenser fan blades when they are slowing down after the machine stops to see the shape of the paddles and how they scoop air so later you can tell if you have one running backwards. variety is necessary as they differ.:yes:

If your talking about the fan in the above pic....I don't think so. If THAT fan were to turn clockwise, it would push air out the center....

The above fan needs to turn counter clockwise.

Here is a good link....with a nice pretty visual...

http://en.wikipedia.org/wiki/Centrifugal_fan

beenthere 07-02-2013 04:53 PM

Quote:

Originally Posted by ddawg16 (Post 1210526)
If your talking about the fan in the above pic....I don't think so. If THAT fan were to turn clockwise, it would push air out the center....

The above fan needs to turn counter clockwise.

Here is a good link....with a nice pretty visual...

http://en.wikipedia.org/wiki/Centrifugal_fan


The fan pic he posted. Is of a squirrel cage that would spin clockwise. Its a forward inclined squirrel cage. A reversed inclined would spin counter clockwise.

ddawg16 07-02-2013 04:56 PM

Quote:

Originally Posted by beenthere (Post 1210586)
The fan pic he posted. Is of a squirrel cage that would spin clockwise. Its a forward inclined squirrel cage. A reversed inclined would spin counter clockwise.

Your talking about this fan?

http://www.diychatroom.com/attachmen...ower-wheel.jpg

Or the one on the other page?

beenthere 07-02-2013 05:04 PM

Quote:

Originally Posted by ddawg16 (Post 1210591)


Yep, that one. Standard forward inclined fan blade. It spins clockwise to move air.

I've changed out more of them then I care to remember. And some bigger then I could lift myself.

ddawg16 07-02-2013 05:18 PM

I've changed out a couple as well....but a bit larger....like this one.....weighs about 1500 lbs, about 5' in dia...driven by a 1000 HP motor....this is what happens when a weld is ground off...about $250K in damage....

It spins CCW.

http://i43.photobucket.com/albums/e3...ps975a7ada.jpg

I'm at a loss as to how the fan your talking about can turn CW (as you look at it in the photo)...sucks air in through the center out out the sides...

justplumducky 07-02-2013 05:27 PM

ddawg~, I did some more googling and found this page with a few different types of squirrel cage wheels, posted by a manufacturer: http://www.rementerprisesinc.com/cen...s-blowers.html It has the type of wheel found in the animation on the page you posted a link to:http://en.wikipedia.org/wiki/Centrifugal_fan

Apparently that animation is a Backward Inclined, or an Airfoil Blade?

Thanks for your reply ddawg - I leaned some more! Thx beenthere.

beenthere 07-02-2013 05:31 PM

Quote:

Originally Posted by ddawg16 (Post 1210608)
I've changed out a couple as well....but a bit larger....like this one.....weighs about 1500 lbs, about 5' in dia...driven by a 1000 HP motor....this is what happens when a weld is ground off...about $250K in damage....

It spins CCW.

http://i43.photobucket.com/albums/e3...ps975a7ada.jpg

I'm at a loss as to how the fan your talking about can turn CW (as you look at it in the photo)...sucks air in through the center out out the sides...


That is a reversed inclined blade.

You ought to see what one looks like that is driven by a 4,000 HP motor.

yuri 07-02-2013 06:02 PM

where do you find those large units? mines?

beenthere 07-02-2013 06:06 PM

Mills.

A little blower may be 150 HP.

ddawg16 07-02-2013 06:15 PM

And in things like this....

http://i43.photobucket.com/albums/e3...87TestTool.jpg


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