Electrical Machine MCQ #15

1) The purpose in breather in a transformer is to

      a) provide insulation to the winding

      b) provide cooling to the winding

      c) extract moisture from the air

      d) reduce the copper loss

2) What is the use of auto-transformer?

      a) Isolating transformer

      b) Variable transformer

      c) Control transformer

      d) Current transformer

3) The open circuit test is conduct in transformer to find?

      a) Copper loss

      b) Core loss

      c) Efficiency

      d) Insulation resistance

4) Which of the following loss is not present in the transformer?

      a) Core loss

      b) Copper loss

      c) Friction loss

      d) Eddy current loss

ANSWER: | 1-c | 2-b | 3-b | 4-c |

5) The no load test is conduct in transformer to find?

      a) Copper loss

      b) Core loss

      c) Efficiency

      d) Magnetizing current and loss  

6) Which chemical is used in the breather of transformer?

      a) Silica

      b) Fiber

      c) Plastic

      d) Silica gel

7) Which winding of the transformer has more cross-sectional area?

      a) High-voltage winding

      b) low-voltage winding

      c) Primary winding

      d) Secondary winding

8) Short-circuit test on transformer is conducted to determine

      a) Hysteresis loss

      b) Core loss

      c) Copper loss

      d) Eddy current loss

ANSWER:  | 5-d | 6-d | 7-b | 8-c |

9) In transformer, which winding has less cross-sectional area?

      a) High-voltage winding

      b) low-voltage winding

      c) Primary winding

      d) Secondary winding

10) Which test is conduct in transformer to determine temperature?

      a) No-load test

      b) Open circuit test

      c) Sumpner’s test

      d) Routine test

11) Harmonics in transformer result in

      a) increase core loss

      b) increase copper loss

      c) magnetic interference with commutation circuit

      d) all of the above

12) The noise resulting from vibration of lamination set by magnetic forces in transformer is termed as,

      a) zoom

      b) hum

      c) boo

      d) None of the above

ANSWER: | 9-a | 10-c | 11-d | 12-b |