THREE PHASE INDUCTION MOTORS QUIZ

Reduced voltage starter can be used with

Slip ring motor only but not with squirrel cage induction motor

None of these

Squirrel cage as well as slip ring induction motor

Squirrel cage induction motor only but not with slip ring motor

TRUE ANSWER : ?
YOUR ANSWER : ?

3-phase wound rotor morors are also called _____ motors.

Synchronous

Commutator

Slip ring

Series

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YOUR ANSWER : ?

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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In a squirrel cage rotor, the bars are not placed parallel to the shaft but are skewed to have ______

Uniform torque

Greater mechanical strength

Less rotor losses

None of the listed here

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Friction and windage loss of a 3 phase induction motor are

Maximum at no load

None of the listed here

Minimum at no load

Remains the same at all loads

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The air gap between stator and rotor of 3-phase induction motor ranges from ______

0.4 mm to 4 mm

4 cm to 6 cm

1 cm to 2 cm

2 cm to 4 cm

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The speed of a squirrel cage induction motor is changed by

None of the listed here

Cascade control

Pole changing

Rheostatic control

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When the rotor of a 3-phase induction motor is blocked, the slip is _____

0

0.1

0.5

1

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An induction motor with 1000 r.p.m. speed will have

2 poles

4 poles

8 poles

6 poles

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Very large 3-phase induction motors (greater than 25 HP) are started _____

Direct on line

By auto transformer starting

None of the listed here

Star-delta starting

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YOUR ANSWER : ?