MCQ On DC Motor: DC Motors Electrical Engineering MCQs

MCQ On DC Motor. Multiple Choice Questions and Answers

 

MCQ On DC Motor

 

In D.C. shunt motors as load is reduced ?

A. the speed will increase abruptly
B. the speed will increase in proportion to reduction in load
C. the speed will remain almost/constant
D. the speed will reduce

View Answer

C. the speed will remain almost/constant

 

A D.C. series motor is that which ?

A. has its field winding consisting of thick wire and less turns
B. has a poor torque
C. can be started easily without load
D. has almost constant speed

View Answer

A. has its field winding consisting of thick wire and less turns

 

If a D.C. motor is to be selected for conveyors, which motor would be preferred ?

A. Series motor
B. Shunt motor
C. Differentially compound motor
D. Cumulative compound motor

View Answer

A. Series motor

 

For starting a D.C. motor a starter is required because ?

A. it limits the speed of the motor
B. it limits the starting current to a safe value
C. it starts the motor
D. none of the above

View Answer

B. it limits the starting current to a safe value

 

Which D.C. motor will be preferred for machine tools ?

A. Series motor
B. Shunt motor
C. Cumulative compound motor
D. Differential compound motor

View Answer

B. Shunt motor

 

MCQ On DC Motor

 

To get the speed of D.C motor below the normal without wastage of electrical energy is used ?

A. Ward Leonard control
B. rheostatic control
C. any of the above method
D. none of the above method

View Answer

A. Ward Leonard control

 

A direct on line starter is used for starting motors ?

A. up to 5 H.P
B. up to 10 H.P
C. up to 15 H.P
D. up to 20 H.P

View Answer

A. up to 5 H.P

 

In DC motor which of the following can sustain the maximum temperature rise ?

A. Slip rings
B. Commutator
C. Field winding
D. Armature winding

View Answer

C. Field winding

 

These days D.C. motors are widely used in ?

A. pumping sets
B. air compressors
C. electric traction
D. machine shops

View Answer

C. electric traction

 

In which of the following applications D.C. series motor is invariably tried ?

A. Starter for a car
B. Drive for a water pump
C. Fan motor
D. Motor operation in A.C. or D.C

View Answer

A. Starter for a car

 

MCQ On DC Motor

 

Which D.C. motor has got maximum self loading property ?

A. Series motor
B. Shunt motor
C. Cumulatively compounded ‘motor
D. Differentially compounded motor

View Answer

D. Differentially compounded motor

 

For which of the following applications a D.C. motor is preferred over an A.C. motor ?

A. Low speed operation
B. High speed operation
C. Variable speed operation
D. Fixed speed operation

View Answer

C. Variable speed operation

 

In dc generator the residual magnetism is of the order of ?

A. 2 to 3 per cent
B. 10 to 15 per cent
C. 20 to 25 per cent
D. 50 to 75 per cent

View Answer

A. 2 to 3 per cent

 

Sparking at the commutator of a D.C. motor may result in ?

A. damage to commutator segments
B. damage to commutator insulation
C. increased power consumption
D. all of the above

View Answer

D. all of the above

 

Speed control by Ward Leonard method gives uniform speed variation ?

A. in one direction
B. in both directions
C. below normal speed only
D. above normal speed only

View Answer

B. in both directions

 

MCQ On DC Motor

 

If the supply voltage for a D.C. motor is increased, which of the following will decrease ?

A. Starting torque
B. Operating speed
C. Full-load current
D. All of the above

View Answer

C. Full-load current

 

Following motor is used where high starting torque and wide speed range control is required ?

A. Single phase capacitor start
B. Induction motor
C. Synchronous motor
D. D.C. motor

View Answer

D. D.C. motor

 

Which motor has the poorest speed control ?

A. Differentially compounded motor
B. Cumulatively compounded motor
C. Shunt motor
D. Series motor

View Answer

D. Series motor

 

As the load is increased the speed of dc shunt motor will ?

A. reduce slightly
B. increase slightly
C. increase proportionately
D. remains unchanged

View Answer

A. reduce slightly

 

The armature torque of the D.C. shunt motor is proportional to ?

A. field flux only
B. armature current only
C. both A. and B
D. none of the above

View Answer

B. armature current only

 

MCQ On DC Motor

 

Which of the following motors one will choose to drive the rotary compressor ?

A. D.C. shunt motor
B. D.C. series motor
C. Universal motor
D. Synchronous motor

View Answer

D. Synchronous motor

 

Why are the D.C. motors preferred for traction applications ?

A. Torque and speed are inversely proportional to armature current
B. Torque is proportional to armature current
C. Torque is proportional to square root of armature current
D. The speed is inversely proportional to the torque and the torque is proportional to square of armature current

View Answer

D. The speed is inversely proportional to the torque and the torque is proportional to square of armature current

 

D.C. shunt motors are used for driving ?

A. trains
B. cranes
C. hoists
D. machine tools

View Answer

D. machine tools

 

Regenerative method of braking is based on that ?

A. back e.m.f. is less than the applied voltage
B. back e.m.f. is equal to the applied voltage
C. back e.m.f. of rotor is more than the applied voltage
D. none of the above

View Answer

B. back e.m.f. is equal to the applied voltage

 

In variable speed motor ?

A. a stronger commutating field is needed at low speed than at high speed
B. a weaker commutating field is needed at low speed than at high speed
C. same commutating field is needed at low speed than at high speed
D. none of the above is correct

View Answer

B. a weaker commutating field is needed at low speed than at high speed

 

MCQ On DC Motor

 

When the armature of a D.C. motor rotates, e.m.f. induced is ?

A. self-induced e.m.f.
B. mutually induced e.m.f.
C. back e.m.f
D. none of the above

View Answer

C. back e.m.f

 

Which D.C. motor has got maximum self relieving property ?

A. Series motor
B. Shunt motor
C. Cumulatively compounded motor
D. Differentially compounded motor

View Answer

A. Series motor

 

Which method of braking is generally used in elevators ?

A. Plugging
B. Regenerative braking
C. Rheostatic braking
D. None of the above

View Answer

A. Plugging

 

Armature reaction in dc motor results ?

A. decrease in speed
B. increase in speed
C. short circuit
D. open circuit

View Answer

B. increase in speed

 

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