Influence of rotor slot shape on the parameters of induction motor

The article deals with the influence of the shape Boucherot's cage on induction motor parameters, which are mainly values of starting torque, breakdown torque, but also power factor, efficiency and starting current. Torque curve of induction motor with Boucherot's cage is characterized by a high value of starting torque with a relatively low starting current. The waveform of the resulting torque characteristics is the sum of characteristic of outer cage and characteristic of the inner cage. These partial waveforms are given by their impedances which are given by active part - so by cross-section of rotor slot, and by reactive part - so by self-inductance respectively reactance which is associated the depth of rotor slot, the width of the rotor tooth, width and height of bar etc. The principle of calculating the reactance and resistance of the machine is given in the article and also to analyze the equivalent circuit according to the choices we derive formulas for equations required torques. We are finding the optimum of shape of rotor slot for the maximum size of the relative starting torque and minimum size of relative starting current while maintaining favorable power factor and efficiency the motor.