Electrical Engineering Questions And Answers :: Dc Motors: part3

Electrical Engineering : Dc Motors QUESTIONS AND ANSWERS :: part3 : 1 to 5

Following Electrical Engineering Multiple choice objective type questions and answers will help you in BSNL JTO, GATE 2014 and IES 2014 examinations :

1.Which of the following method of speed control of D.C. machine will offer minimum efficiency ?

Voltage control method
Field control method
Armature control method
All above methods

2.Sparking, is discouraged in a D.C. motor because

it increases the input power con-sumption
commutator gets damaged
both (a) and (b)
none of the above

3.The speed of a D.C. motor can be varied by varying

field current
applied voltage
resistance in series with armature
any of the above

4.If I2 be the armature current, then speed of a D.C. shunt motor is

independent of Ia
proportional to la
varies as (Ia)
varies as la

5.Which D.C. motor is generally preferred for cranes and hoists ?

Series motor
Shunt motor
Cumulatively compounded motor
Differentially compounded motor

More Dc Motors QUESTIONS AND ANSWERS available in next pages

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