15. In case of centrifugal pumps the starting torque is generally
A. double the running torque
B. slightly more than running torque
C. same as running torque
D. less than running torque

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16. Motor preferred for synthetic fibre mills is
A. D.C. Series motor
B. reluctance motor
C. D.C. Shunt motor
D. synchronous motor

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17. Reluctance motor is a
A. self-starting type synchronous motors
B. low torque variable speed motor
C. variable torque motor
D. low noise, slow speed motor

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18. Ward-Leonard controlled d.c. drives are generally used for
A. light duty excavators
B. medium duty excavators
C. heavy duty excavators
D. all of these

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19. In case of contactors the ratio of the inservice period to the entire period,expressed as a percentage is known as
A. duty
B. load factor
C. class of contact
D. none of these

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20. A magnetic amplifier can be used for the control of
A. current
B. voltage
C. speed
D. all of these

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21. In a contactor, overheating of contacts may result from
A. high inductive loads
B. copper oxide on contacts
C. carrying load continuously for a longer time
D. all of these

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