Rockwell Automation 150 MNL/SMC DIALOG+/APP-PROD GUIDE - Manual (Page 164)

10-2 Reference
Torque and Horsepower (cont.) Torque is merely a turning effort. In the previous illustration, it takes
one pound at the end of the one foot wrench to turn the shaft at a
steady rate. Therefore, the torque required is one pound × one foot, or
one foot-lb. If the wrench were turned twice as fast, the torque
required would remain the same, provided it is turned at a steady rate.
Horsepower, on the other hand, takes into account how fast the shaft
is turned. Turning the shaft rapidly requires more horsepower than
turning it slowly. Thus, horsepower is a measure of the rate at which
work is done. By definition, the relationship between torque and
horsepower is as follows:
In the above example, the one pound of force moves a distance of:
To produce one horsepower, the shaft would have to be turned at
rate of:
For this relationship, an equation can be derived for determining
horsepower output from speed and torque.
For this relationship, full-load torque is:
1 Horsepower 33,000 ft.-lbs./Min. =
2 Ft.
π ×
1 Lb. or 6.68 ft.-lb
×
1 HP 33,000 ft.-lbs./Min.
×
6.28 ft.-lbs./Revolutio
------------------------------------------------------- 5,250 R P =
HP
RPM
×
Torqu
×
30,00
-------------------------------------- = or
RPM Torqu
×
5,25
-----------------------------
Full-load Torque in ft.-lb
HP 5,25
×
Full-load RPM
---------------------------- =