THREE PHASE INDUCTION MOTORS QUIZ

One of the speeds of a 2 speed squirrel cage induction motor is 800 rpm. The other speed will be _____

400 rpm

1200 rpm

1600 rpm

2400 rpm

TRUE ANSWER : ?
YOUR ANSWER : ?

The term cogging is associated with

Dc series motors

Three phase transformer

Compound generators

Induction motors

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

95 to 98 %

60 to 90%

80 to 90%

99%

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The maximum torque of a 3-phase induction motor under running conditions is

Directly proportional to rotor resistance

Inveresly proportional to supply voltage

None of the listed here

inversely proportional to rotor reactance at standstill

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The 3- phase induction motor is so designed that the rotor should have ______ under running conditions.

Large slip

high resistance

High reactance

Low resistance

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In induction motor, percentage slip depends on

Supply frequency

None of these

Supply voltage

Copper losses in motor

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In a double squirrel cage induction motor, the outer cage winding has _______

High inductance

None of the listed here

Low resistance

High resistance

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The shaft of induction motor is made of

Stiff

Flexible

Any of the listed here

Hollow

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

Leakage reactances are decreased

Leakage reactances are increased

No load current is decreased

None of the listed here

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The shaft of an induction motor is made of

Cast iron

Stainless steel

High speed steel

Carbon steel

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