DC Motors Mcqs - Set 7

1)   If the load on a DC shunt motor is increases, its speed is slightly reduced due to______________?

a. increase in armature current
b. increase in flux
c. decrease in reactance
d. decrease in back emf
Answer  Explanation 

ANSWER: decrease in back emf

Explanation:
No explanation is available for this question!


2)   In which of the following device the generated emf and armature current are in the opposite directions?

a. dc generator
b. dc motor
c. transformer
d. all of the above
Answer  Explanation 

ANSWER: dc motor

Explanation:
No explanation is available for this question!


3)   With the increase in temperature, the speed of DC shunt motor____________?

a. decreases
b. increases
c. remain same
d. none of the above
Answer  Explanation 

ANSWER: increases

Explanation:
No explanation is available for this question!


4)   With the increase in temperature, the speed of DC series motor______________?

a. decreases
b. increases
c. remain same
d. none of the above
Answer  Explanation 

ANSWER: decreases

Explanation:
No explanation is available for this question!


5)   If the field winding resistance of a DC shunt motor is increases, its speed will____________?

a. decreases
b. increases
c. remains same
d. none of the above
Answer  Explanation 

ANSWER: increases

Explanation:
No explanation is available for this question!


6)   Which of the following method is used for the speed control of DC shunt motor?

a. voltage control method
b. flux control method
c. rheostat control method
d. all of the above
Answer  Explanation 

ANSWER: all of the above

Explanation:
No explanation is available for this question!


7)   A dc series motor should not be started on no load because it would___________?

a. not develop starting torque
b. fail to start without load
c. run at dangerously high speed
d. draw more current without producing sufficient torque
Answer  Explanation 

ANSWER: run at dangerously high speed

Explanation:
No explanation is available for this question!


8)   In a DC motor the inter-pole winding is connected in________________?

a. series with field winding
b. series speed armature winding
c. parallel big field winding
d. parallel with armature winding
Answer  Explanation 

ANSWER: series speed armature winding

Explanation:
No explanation is available for this question!


9)   Armature reaction in dc motor results___________?

a. decrease in speed
b. increase in speed
c. short circuit
d. open circuit
Answer  Explanation 

ANSWER: increase in speed

Explanation:
No explanation is available for this question!


10)   Which of the following test can be performed on DC series motor?

a. Swinburne test
b. Hopkinson test
c. Brake test
d. Field test
Answer  Explanation 

ANSWER: Field test

Explanation:
No explanation is available for this question!


11)   Ward Leonard method of speed control is basically a______________?

a. field control method
b. armature controlled method
c. field diverter
d. frequency control method
Answer  Explanation 

ANSWER: armature controlled method

Explanation:
No explanation is available for this question!