Thread: Newbie pitch
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Old 11-27-2008, 03:28 AM   #38 (permalink)
Christ
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Quote:
Originally Posted by some_other_dave View Post
Forgive the side-tracking, but I need to point out the above statement is incorrect. When you use gear reduction (and pulley reduction is just a different type of gear reduction), you still transmit all of the power. The torque is what gets multiplied by the gear ratios, as well as the RPM. But the power stays the same.

-soD
HP is a relative number derived from TQ...

To calculate HP: (TQxRPM)/5252=HP

That said, if torque is multiplied or divided, as the case may be, so is HP.

If an engine has 100 LBFT of torque at 1000 RPM,

100x1000 = 100000
100000/5252 = 19 (horsepower @ 1000RPM)

What you're saying is taking the speed of the driven object and deriving horsepower from it.

Example

10 LBFT @ accessory pulley, 10000 RPM (10:1 from engine)

10 x 10000 = 100000

100000/5252 = 19HP

At least from what I remember of physical science in HS, that's correct.
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Last edited by Christ; 11-27-2008 at 02:25 PM.. Reason: incorrect information
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