24) Which method is NOT correct to change the direction of rotation of a DC series motor?

By changing the polarity of supply terminal

By changing the terminal of series field

By interchanging brush contact position

By changing the terminals of the armature

Answer is:

By changing the polarity of supply terminal

ISRO Technician-B Electrician Question Paper - 2017 (Set - 1) with Answer Key

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25) The rotational speed of a DC shunt motor can be increased above its full speed by

Increasing field current

Decreasing field current

Increasing armature current

Decreasing armature current

Answer is:

Decreasing field current

26) Efficiency of a power transformer is in the order of

60%

70%

80%

97%

Answer is:

97%

27) In a step down single phase power transformer, primary voltage is 22 kV and secondary voltage is 220V. When secondary is delivering a load current of 100 A, primary current is

0.1A

100A

10000A

Answer is:

1A

28) What will be the copper loss at half load of a single phase transformer which is having a copper loss of 1000 W at full load?

1000 W

500 W

250 W

125 W

Answer is:

250 W

ISRO Technician-B Electrician Question Paper - 2017 (Set - 1) with Answer Key

For more MCQ's Click Here

24) Which method is NOT correct to change the direction of rotation of a DC series motor?

By changing the polarity of supply terminal

ISRO Technician-B Electrician Question Paper - 2017 (Set - 1) with Answer Key

Related ISRO Technician-B Electrician Question Paper - 2017 (Set - 1) with Answer Key

25) The rotational speed of a DC shunt motor can be increased above its full speed by

Decreasing field current

26) Efficiency of a power transformer is in the order of

97%

27) In a step down single phase power transformer, primary voltage is 22 kV and secondary voltage is 220V. When secondary is delivering a load current of 100 A, primary current is

1A

28) What will be the copper loss at half load of a single phase transformer which is having a copper loss of 1000 W at full load?

250 W

ISRO Technician-B Electrician Question Paper - 2017 (Set - 1) with Answer Key