UPPCL EE :Electrical Machines Quiz 3

The slip of a 3- ϕ induction motor operating in its stable region

Consider two statements:

Statement I : As resistance of IM rotor is increased, the maximum torque produce by it increases.

Statement II : As resistance of IM rotor is increased, the slip at which maximum torque occurs increases.

In 4 pole, 50 Hz 3- ϕ induction motor. The rotor frequency is 5 Hz. The speed of stator magnetic field with respect to rotor will be:

Which of the following option is correct for the given rotors, if they are arranged in increasing order of starting torque?

(i) slip ring

(ii) double cage

(iii) Deep bar

(iv) Narrow squirrel cage

Which of the following statement is not correct about squirrel cage and wound rotor motor of some power rating?

For 3-ϕ induction motor, maximum torque is two times of full load torque and starting torque is equal to full load torque. Slip value corresponding to maximum torque is ________ %

A three-phase, 60 Hz, 25 HP, wye-connected induction motor operates at a shaft speed of almost 1800 r.p.m. at no load and 1650 r.p.m. at full load. The number of poles of the motor is

A 3-ϕ, 4 pole, 50 Hz induction motor has rotor copper losses equal to 300 W. What is the torque developed by this motor at 4% of slip?

For an induction machine, acting as a motor, rotor rotates in clockwise direction. If same machine rotates in clockwise direction but at super synchronous speed, then,

1) Slip > 1

2) Machine delivers active power towards supply

3) Theoretical super synchronous speed is Infinite

Choose the correct option

In a 4 pole 50 Hz single-phase induction motor, if the rotor rotating with forward slip of 0.05 then find rotor frequency due to backward rotating field.