5. Torque
By varying the resistance within the rotor bars of a squirrel cage rotor, you can vary the amount of torque developed. By increasing rotor resistance, torque and slip are increased. Decreasing rotor resistance decreases torque and slip.
Motor horsepower is a relation of motor output speed and torque (expressed in lbft):
Motor horsepower is a relation of motor output speed and torque (expressed in lbft):
HP = (RPM * Torque) / 5250 — eq. 5
The operating torques of an electric motor are defined as (Ref. NEMA MG 11993, Part 1, p.12):

Full Load Torque: The full load torque of a motor is the torque necessary to produce its rated horsepower at fullload speed. In pounds at a foot radius, it is equal to the hp times 5250 divided by the fullload speed.

Locked Rotor Torque: The lockedrotor torque of a motor is the minimum torque which will develop at rest for all angular positions of the rotor, with rated voltage applied at rated frequency.

PullUp Torque: The pullup torque of an alternating current motor is the minimum torque developed by the motor during the period of acceleration from rest to the speed at which breakdown torque occurs. For motors which do not have a definite breakdown torque, the pullup torque is the minimum torque developed up to rated speed.

Breakdown Torque: The breakdown torque of a motor is the maximum torque which it will develop with rated voltage applied at rated frequency, without an abrupt drop in speed.
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