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rotorque
9th Oct 2005, 11:26
Hi guys/girls,

How do you calculate torque....??

I have been researching tapered shaft locking devices and have gotten differing results from suppliers when giving RPM and Shaft size........

These are the figures:

130 Hp (96Kw) driving a 40-50 mm shaft at 370 to 400 RPM.

I have been given 4100Nm and 2570Nm for the same equation...???!!!

Can someone run us through the calculations for calculating torque?

Cheers


edited to add this equation as I previously understood it....now I just have no idea

Mt = Nt/2 pi R
Nt being transmitted power
But I must lose something in converting the HP to a usable unit.

Graviman
9th Oct 2005, 11:57
Torque = Power / Rot_Speed But remember Rot_Speed must be in radians per second.

Using your numbers:

Torque = 96000 Watts / (385 RPM * (2*PI/60) ) = 2381 Nm

Don't forget that the input power is not the engine power, but the power transmitted by the shaft...

Mart

rotorque
10th Oct 2005, 00:53
Thanks Graviman,

Interesting that a decrease in RPM increases torque.........

"why is it so"

Don't have to go into too much detail, I'm sure 4-5 years at uni would answer the question..... :{