Finding Braking Torque

Full-load motor torque is needed to determine the required braking torque of a motor.

To calculate the braking torque of a motor:

T =( 5252 x HP)/rpm


T = full-load motor torque (in lb-ft)
5252 = constant (33,000 divided by 3.14 x 2 = 5252)
HP = motor horsepower
rpm = speed of motor shaft

• Example: What is the braking torque of a 40 HP, 240V motor rotating at 1725 rpm?

T = (5252 x HP)/rpm

T = (5252 x 40)/1725

T = 210,080/1725

T = 121.8 lb-ft