THREE PHASE INDUCTION MOTORS QUIZ

Size of a high speed motor as compared to low speed motor for the same HP will be

Same

Smaller

Bigger

Any of the listed here

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The shape of the torque/slip curve of induction motor is

Straight line

Hyperbola

Parabola

Rectangular parabola

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If an induction motor is running at slip S, then rotor output is ______

(S-1) × rotor input

(1+S) × rotor input

S × rotor input

(1-S) × rotor input

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The frequency of rotor current in a 6-pole , 50 Hz, 3-phase induction motor running at 950 rpm is

5 Hz

0.05 Hz

2.5 Hz

1.5 Hz

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If the supply voltage of a 3-phase induction motor is increased two times, then torque is _______

Decreased four times

Increased two times

Decreased two times

Increased four times

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

Greater mechanical strength

None of the listed here

Uniform torque

Less rotor losses

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In medium sized induction motor, the slip is generally around

0.4 %

14%

4 %

0.04 %

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The maximum torque in an induction motor depends on

Frequency

Square of supply voltage

All of the listed here

Rotor inductive reactance

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The good power factor of an induction motor can be achieved if the average flux density in the air gap is

Small

Large

Infinity

Absent

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In induction motor, percentage slip depends on

Copper losses in motor

None of these

Supply voltage

Supply frequency

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