# Identifying proper rotation of squirrel cage wheel



## yuri (Nov 29, 2008)

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:


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## biggles (Jan 1, 2008)

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...


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## old_squid (Oct 31, 2012)

Your conclusion is correct.


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## justplumducky (Aug 7, 2009)

Thank you for the confirmation, old_squid.



> 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:



yuri said:


> 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).


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## ddawg16 (Aug 15, 2011)

yuri said:


> *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


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## beenthere (Oct 11, 2008)

ddawg16 said:


> 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.
> 
> ...



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.


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## ddawg16 (Aug 15, 2011)

beenthere said:


> 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?










Or the one on the other page?


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## beenthere (Oct 11, 2008)

ddawg16 said:


> Your talking about this fan?



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.


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## ddawg16 (Aug 15, 2011)

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.



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...


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## justplumducky (Aug 7, 2009)

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/centrifugal-inline-fans-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.


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## beenthere (Oct 11, 2008)

ddawg16 said:


> 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.
> 
> ...



That is a reversed inclined blade.

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


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## yuri (Nov 29, 2008)

where do you find those large units? mines?


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## beenthere (Oct 11, 2008)

Mills. 

A little blower may be 150 HP.


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## ddawg16 (Aug 15, 2011)

And in things like this....


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## yuri (Nov 29, 2008)

NASA?

always wanted to see the equipment in mines and mills and we have lots up North here and in Ontario etc. Friend of mine was in Thompson/ INCO but I did not get up there in time.

Had a 200 hp 3 ph motor with Star Delta starter on a blower for a office tower. wheel was 10 ft in diameter and had 20 ft long belts. scared the heck out of yah when that starter was not setup properly. and a 1000 ton centrivac chiller. lots of interesting stuff mankind has invented.:yes:

the good ole days, strong like bull, removed lots of boilers, oil tanks, cast iron heat exchangers from oil furnaces in war time homes. now I just use the ole brain instead.:laughing:


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## ddawg16 (Aug 15, 2011)

Justplum...thanks for suggesting I look closer.....I saw the first animation...in the link and stopped there...but when you read down further....you find the description of the 3 types...

Learn something every day...

I stand corrected............

And Yuri...not NASA....that is the tool for the Boeing 787 front fuselage...

That autoclave is 30' in dia....the door weighs about 40 tons...


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## biggles (Jan 1, 2008)

if the filter gets saturated the squirrel is next then the coil...major bucks and forget the operation it is shot all of these dirt catches cause icing..right out to the compressor....


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## justplumducky (Aug 7, 2009)

Luv those pics ddawg, yepper. 

Thx biggles- is that a residential blower wheel? If so, do you know how long it took to get that way?


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## biggles (Jan 1, 2008)

that could be a year or so with pets and carpets in the house the coil was packed above the fan section ....large tonnage residential unit.the real kick in the buuutt... is if the A coil is dripping water right on top of a heat exchanger with a furnace and A coil system air handler.that heat EX will rot out in one summer season,and leak carbon monox into the space in the winter...


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## justplumducky (Aug 7, 2009)

Sounds like a very expensive (not to mention dangerous) kick in the butt! Thx for that tip (and pic).


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## PoleCat (Sep 2, 2009)

I have reinstalled a few cages backwards in my time and they still blow air, just not as much. After a couple of times you make a better effort to pay attention to what you are doing.


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