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View Full Version : How to find a torque for fan wings ?


alexjohn
Jul 30, 2012, 07:00 AM
I have 2 fan wings weight 500 g each... attached by shaft and gear box... diameter is 15 cm... total wing span is 170 cm... need to rotate with 1000 rpm.how can I find the required torque or hp I need to rotate them??

ebaines
Jul 30, 2012, 09:05 AM
i have 2 fan wings weight 500 g each ...attached by shaft and gear box...diameter is 15 cm ...total wing span is 170 cm ...need to rotate with 1000 rpm.how can i find the required torque or hp i need to rotate them ???

It's going to depend very much on the amount of air this fan is to move. You need to first determine theflow in cubic feet per minute (CFM) the fan will produce. From that you could calculate the speed of the wind the fan creates (CFM divided by area of the fan) and then you can estimate the force required to accelerate that volume of air, and finally determine torque from an estimate of the moment arm of the force on the fan blades. This would give a lower bound estimate for sizing the motor.