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Old 06-29-2008, 08:21 PM   #14 (permalink)
Gregte
EcoModding Apprentice
 
Join Date: May 2008
Location: South Dakota
Posts: 117

GMC Sonoma - '94 GMC Sonoma
90 day: 36.97 mpg (US)
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Quote:
Originally Posted by ttoyoda View Post
Well if you want share your raw data we can check all your math at least
Did you take a pic of your setup?
Do you still have the measurement of the lever arm etc?
The lever arm used was a bracket on the motor housing that measured 3.5 inches from motor shaft center. I measured 1 pound of force pulling perpendicularly from the radius between shaft and the point on the bracket when I attached a fish scale. This tells me the force in ft. lbs. was 0.2916.

I used 3450 RPM X 0.2916 / 5252 to get 0.19 HP.

No pics, but just imagine a basically cylindrical motor laying on a steel table top. It is free to roll. However, when it tries to roll it cannot because I have a fish scale attached to a bracket on the motor. I see to it that the scale is pulling perpendicular to a radius which extends from the motor shaft to the scale's attaching point. This radius is 3.5 inches long. Therefore, with the motor and fan running, I divide the fish scales reading (1 pound) by 3.428 (3.428 is 12 inches/ 3.5 inch radius) to get the actual foot pounds of torque which is 0.2917 ft. lbs.

I assume the motor speed is 3450 because it's plate says it is. The actual RPM of the fan (it's clutch is not engaged, but it still spins) is irrelevant. Only the torque load seen by the motor and the motor's RPM are needed.

Anyway, I gotta get to work now lest I have even bigger problems ;-)
Later
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