Tests on DC Motor Objective Questions
1. One of the main advantages of Swinburne’s test is that it
(a) is applicable both to shunt and compound motors
(b) needs one running test
(c) is very economical and convenient
(d) ignores any charge in iron loss
2. The main disadvantage of Hopkinson’s test for finding the efficiency of shunt d.c. motors is that it
(a) requires full-load power
(b) ignores any change in iron loss
(c) needs one motor and one generator
(d) requires two identical shunt machines
3. The most economical method of finding no-load losses of a large d.c. shunt motor is — test.
(a) Hopkinson’s
(b) Swinburne’s
(c) retardation
(d) Field’s
4. Retardation test on a d.c. shunt motor is used for finding — losses.
(a) stray
(b) copper
(c) friction
(d) iron
Tests on DC Motor Objective Questions
5. The main thing common between Hopkinson’s test and Field’s test is that both
(a) require two electrically-coupled series motors
(b) need two similar mechanically-coupled motors
(c) use negligible power
(d) are regenerative tests
6. The usual test for determining the efficiency of a traction motor is the ………….. test.
(a) Field’s
(b) retardation
(c) Hopkinson’s
(d) Swinburne’s
ANSWERS
1. c 2. d 3. b 4. a 5. b 6. a
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