THREE PHASE INDUCTION MOTORS QUIZ

Less maintenance troubles are experienced in case of

Squirrel cage induction motor

Slip ring induction motor

None of these

Both (A) and (B)

TRUE ANSWER : ?
YOUR ANSWER : ?

Which of the following component is usually fabricated out of silicon steel?

Stator core

Bearings

None of these

Shaft

TRUE ANSWER : ?
YOUR ANSWER : ?

If the air gap between the rotor and stator of a 3-phase induction motor is increased, then_______

Leakage reactances are decreased

No load current is decreased

None of the listed here

Leakage reactances are increased

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YOUR ANSWER : ?

Slip of an induction motor is negative when

None of these

Rotor speed is less than the synchronous speed of the field and are in the same direction

Rotor speed is more than the synchronous speed of the field and are in the same direction

Magnetic field and rotor rotate in opposite direction

TRUE ANSWER : ?
YOUR ANSWER : ?

If the frequency of 3-phase supply to the stator of a 3-phase induction motor is increased, then synchronous speed ______

Remains unchanged

Is increased

None of the listed here

Is decreased

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YOUR ANSWER : ?

The efficiency of an induction motor can be expected to be nearly

80 to 90%

95 to 98 %

99%

60 to 90%

TRUE ANSWER : ?
YOUR ANSWER : ?

The frame of an induction motor is usually made of

Bronze

Aluminium

Cast iron

Silicon steel

TRUE ANSWER : ?
YOUR ANSWER : ?

The direction of rotation of field in a 3 phase induction motor depends upon _____

Magnitude of supply voltage

Phase sequence of supply voltage

Number of poles

Supply frequency

TRUE ANSWER : ?
YOUR ANSWER : ?

The starting torque of a squirrel cage induction motor is

Low

Negligible

Slightly more than full load torque

Same as full load torque

TRUE ANSWER : ?
YOUR ANSWER : ?

In an induction motor, the ratio of rotor cu loss and rotor input is given by

1-S

S/1-S

S

1/S

TRUE ANSWER : ?
YOUR ANSWER : ?