Polyphase Induction Motors Set 2

Increases the load torque ✘ Decreases the starting torque ✘ Increases the starting torque ✘ None of the above ✔

Resistance is inserted in the stator ✘ Reduced voltage is applied to the stator ✘ Resistance is inserted in the rotor ✘ Applied voltage per stator phase is 57.7% of the line voltage ✔

Parabola ✘ Hyperbola ✘ Rectangular parabola ✘ Straight line ✔

Star connected only ✘ Delta connected only ✘ Both (A) and (B) ✘ None of the above ✔

Reduce windage losses ✘ Reduce eddy currents ✘ Reduce accumulation of dirt and dust ✘ Reduce magnetic hum ✔

Power factor at starting is high as compared to that while running ✘ Power factor at starting is low as compared to that while running ✘ Power factor at starting in the same as that while running ✘ None of these ✔

Slip ✘ Rotor current ✘ Running torque ✘ Line voltage ✔

Dependent on the shaft loading ✘ Dependent on the number of slots ✘ Slip times the stand still e.m.f. induced in the rotor ✘ None of the above ✔

Bigger ✘ Smaller ✘ Same ✘ Any of the above ✔

Less than 1 % ✘ 0.01% ✘ 0% ✘ 0% ✔