Testing Of D.C. Machines - MCQs with answers

Testing Of D.C. Machines - MCQs with answers


Q1. Out of different methods available for testing of d.c. motors, Swinburne’s test and Hopkinson’s test are commonly used in practice on

A. Shunt generators
B. Series motors
C. Shunt motors
D. All of these

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ANSWER: C. Shunt motors



Q2. Swinburne’s test and brake tests

A. Both are direct method of testing
B. Direct method of testing, indirect method of testing
C. Indirect method of testing, direct method of testing
D. Both are indirect method of testing

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ANSWER: C. Indirect method of testing, direct method of testing



Q3. Swinburne’s test can be performed at

A. Any load
B. Only no load
C. Only full load
D. Only half load

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ANSWER: B. Only no load



Q4. While performing Swinburne’s test, the iron losses are assumed to be

A. Constant
B. Absent
C. Variable
D. None of these

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ANSWER: A. Constant



Q5. The speed in d.c. machine can be measured by using

A. Anemometer
B. Tachometer
C. Voltmeter
D. Ammeter

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ANSWER: B. Tachometer



Q6. While carrying out brake tests if the belt snaps, then the motor will

A. Rotate at reduced speed but in forward direction
B. Rotate at increased speed but in forward direction
C. Rotate at reduced speed but in backward direction
D. Rotate at increased speed but in backward direction

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ANSWER: B. Rotate at increased speed but in forward direction



Q7. While performing retardation tests, the machine whose test is to be taken is run at a speed which is

A. Slightly less than its rated speed
B. Equal to its rated speed
C. Slightly greater than its rated speed
D. All of these

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ANSWER: C. Slightly greater than its rated speed



Q8. The rotational or stray losses includes

A. Iron losses only
B. Iron losses, friction and windage losses
C. Iron losses, copper losses, friction and windage losses
D. None of these

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ANSWER: C. Iron losses, copper losses, friction and windage losses



Q9. The rotational losses in d.c. machines is equal to the

A. Kinetic energy of armature
B. Half of the kinetic energy of armature
C. Square of the kinetic energy of armature
D. Rate of change of kinetic energy

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ANSWER: D. Rate of change of kinetic energy



Q10. In regenerative test, the supply is given to the motor

A. To account for losses
B. To drive generator
C. Both (a) and (b)
D. None of these

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ANSWER: A. To account for losses



Q11. The back to back test is best suited for

A. Small machines
B. Medium size machines
C. Large machines
D. All of these

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ANSWER: C. Large machines



Q12. For performing Hopkinson’s test two identical machines are required which are mechanically coupled. The iron losses in the two machines

A. Can be obtained separately
B. Cannot be separated
C. Both (a) and (b)
D. None of these

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ANSWER: B. Cannot be separated



Q13. The test which can be performed on the d.c. series motor is

A. Brake test
B. Hokinson’s test
C. Swinburne’s test
D. Field test

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ANSWER: D. Field test



Q14. To perform field test on d.c. machines two motors are required. The motors used are

A. Series motors
B. One will be series motor and other will be shunt motors
C. Shunt motors
D. None of these

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ANSWER: A. Series motors



Q15. The difference between field test and regenerative test is that

A. Field test requires two identical machines while regenerative test requires only one machine
B. In field test iron losses can be separated while in regenerative test it cannot
C. In field test generator output is not fed back to the motor while in regenerative test generator output is fed back to the motor
D. All of these

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ANSWER: C. In field test generator output is not fed back to the motor while in regenerative test generator output is fed back to the motor



Q16. The most common method used to check for shorted windings is to perform

A. Field test
B. Drop test
C. Regenerative test
D. Brake test

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ANSWER: B. Drop test


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    Discussion

  • RE: Testing Of D.C. Machines - MCQs with answers -SACHIN (10/08/17)
  • Sir please send me the reasons or justification why these answers are selected....
  • RE: Testing Of D.C. Machines - MCQs with answers -manjunatha g (10/07/17)
  • sir/madum this answers is right but why this answer is selected give proper reason for all question.sir please send reason for all question qickly sir please.