Types of Starters in Three Phase Induction Motor - MCQs with Answers

Types of Starters in Three Phase Induction Motor - MCQs with Answers

Q1. While using stator resistance starter with 3 phase induction motor, the resistances of the starter are kept at

a. Maximum
b. Minimum
c. Half of the maximum value
d. None of these

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Q2. When stator resistances are starter is used, the factor by which stator voltage reduces is say x. If x<1, then due to stator resistance starter, the starting torque

a. Increases by fraction x
b. Reduces by fraction x ∧ 2
c. Reduces by fraction x
d. Increases by fraction x ∧ 2

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Q3. An autotransformer starter is suitable for

a. Star connected induction motor
b. Delta connected induction motor
c. Both (a) & (b)
d. None of these

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Q4. The cheapest starter for induction motor is

a. Stator resistance starter
b. Autotransformer starter
c. Star-delta starter
d. Rotor resistance starter

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Q5. Windings of star-delta starter while starting and during running are connected in

a. Star, delta
b. Delta, delta
c. Star, star
d. Delta, star

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Q6. The advantages of star-delta starter over other types of starter is

a. Cheapest of all
b. Maintenance free
c. Both (a) & (b)
d. None of these

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Q7. When rotor resistance starter is used with induction motor then

a. Only starting current is limited
b. Only starting torque is limited
c. Both starting current and starting torque are limited
d. Neither starting current nor starting torque is limited

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Q8. Direct online starter also called D.O.L. starter is used for motors having capacity

a. Less than 5 h.p.
b. Less than 10 h.p.
c. Greater than 10 h.p.
d. For any capacity motor

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Q9. The NO contact and NC contact of D.O.L. starter is normally

a. Open, closed
b. Closed, open
c. Open, open
d. Closed, closed

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Q10. A 3 phase induction motor in a short circuit current is equal 3 times of the full load current. If the full load slip is 2%, then the starting torque as a percentage of full load torque is

a. 6% of full load torque
b. 18% of full load torque
c. 36% of full load torque
d. None of these

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Q11. In textile machines, to avoid breaking of threads, soft starters are used. The commonly used method in soft starter is

a. Direct online method
b. Star-delta method
c. Thyristor voltage controller method
d. Thyristor current controller method

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