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Pull-out torque

Stan Zurek, Pull-out torque,, {accessed 2021-01-25}
reviewed by Jeanete Leicht, 2013-02-05

Pull-out torque or breakdown torque1) - a point on the torque curve of electric motors, with slightly different meaning for a synchronous motor and an induction motor.

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Pull-out torque for a synchronous motor2)

S. Zurek, Encyclopedia Magnetica, CC-BY-4.0

Synchronous motors

In synchronous motors the value of pull-out torque is a maximum value of torque which allows a synchronous motor to remain in synchronism without “pulling out” of step or synchronism.

The value of pull-out torque is always higher than value of pull-in torque and can be between 1.25 - 3.5 of the nominal full-load torque.3)

Typically, during normal operation the torque of the load should not exceed the value of the pull-out torque.

Breakdown torque for an induction motor4)5)

S. Zurek, Encyclopedia Magnetica, CC-BY-4.0

Induction motors

For induction or asynchronous motors the value of breakdown torque is usually synonymous with the peak value on the torque curve.6)

If the load torque is greater than the pull-out torque then such motor will slow down significantly and if the load torque is not reduced it will stall.

See also


pull-out_torque.txt · Last modified: 2020/12/07 00:22 by stan_zurek

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