The Steady-State Torque Equation of Induction Motors with U-Shaped Iron Bridges in the Rotor Slots

In this paper a modified torque equation for inverter-fed induction motors with U-shaped iron bridges in the rotor is presented. The equation is derived from a modified equivalent circuit with a contsnt bridge voltage introduced in the rotor circuit. A simplified method to estimate the pull-out torque is also presented. This method can be used in conjunction with the conventional equivalent circuit.