3450 rpm 24" 1 1/5hp fan blade?

I am at a loss for who to turn to, so I was hoping that somewhere here could point me in the right direction. I am looking for a source for a

24" (or 23" or 22") fan blade, rated for 3450 rpm, on a 1 1/2 hp motor. It will need to move a lot of air, but the exact amount is not critical. If anyone has any info or can help me in any way, I'd greatly appreciate it. Thanks in advance.

Tim

Reply to
timinohio
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Reply to
Ignacio Simón Yarza

Your not really specific at what you want try

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|Fan+Blades,&prod_level_selected=Fan%20Blade Shaft size and connection would be very important.

Reply to
SQLit

Shaft size is likely to be 5/8". I say likely, because I don't have the motor in hand yet. Connection would be whatever is required to mate the blade to the shaft. Thanks for everyone's help so far.

I need a big (23" or 24" diameter) blade, moving a lot of air; I will get the motor necessary to drive the blade.

Grainger has NO blades rated for 3450rpm. There are none in their catalog and customer service can't find any in their cross-reference material.

Reply to
timinohio

OK, a little more research has revealed fan laws to me - from what I can see, IF size and pressure stay the same, HP must increase by the cube of the ratio of the increased RPM? HPa = HPb * (RPMa/RPMb)^3. To double the RPMs, I'd need 8 times the hp?

If a blade rated for 1/2hp at 1725rpm is turned at 3450rpm, the new hp is 1/2 * (3450/1725)^3, or 4 hp? Can someone tell me if this is correct? Since fan blade diameter is constant, I've dropped it from the equation.

If a blade it rated for 1725 rpm, how fast can I turn it before it explodes? I see a lot of blades rated at various rpm/hp combinations. Thanks again for any help anyone can give me.

Tim

Reply to
timinohio

I will add some comments to get numbers completely done and to have a rule of thumb to estimate and roughly predict flow on a fan. The purpose is to establish a relationship between rpms and fluid flow:

1) Calculate the volume in which the fan might be circunscribed, we name it Vcyl. 2) Multiply by the number of blades, we name it Vturn 3) Multiply by rpm and we get the maximum theoretical volume flux.

volume flux per minute OK, a little more research has revealed fan laws to me - from what I

Reply to
Ignacio Simón Yarza

never seen a fan balanced for that speed exept for a couple large boiler centrifugal draft fans.

3450 at 24 inches maybe 30 lbs of steel? let me know when you start it as i would like to leave the room
Reply to
PCK

(snip)

It certainly will fail catastrophically at some speed above rated ... probably by throwing a blade or part of a blade followed by violent shaking from the imbalance. Failures like this may cause personal injury or death. The manufacturer is the one to ask about speed.

If you exceed the ratings, I think you're all alone on very thin ice. 3450 is very fast for a fan. At best, it will be noisy.

Roby

Reply to
Roby

Then consider changing the motor rpm to match the fan blades.

I tilt at windmills all of the time and have found that changing in mid design is sometimes necessary.

Reply to
SQLit

I think that the original recommendation to me to use a 3450 rpm motor was an attempt to extract maximum airflow from a given blade. I think that, as SQLit has suggested, my best course of action would be to find a premium blade, designed for my currect 1/2 hp, 1725 rpm motor. Thanks to all that had suggestions and comments.

Tim

Reply to
timinohio

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