DC Motors MCQ Multiple Choice Questions Answers

Q: 1. A D.C. series motor is that which

Correct Answer is: has its field winding consisting of thick wire and less turns

Q: 2. A direct on line starter is used: for starting motors

Correct Answer is: iip to 5 H.P.

Q: 3. A three point starter is considered suitable for

Correct Answer is: shunt as well as compound motors

Q: 4. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of

Correct Answer is: current in the conductor aovtaat of conductor

Q: 5. As -the load is increased the speed of D.C. shunt motor will

Correct Answer is: reduce slightly

Q: 6. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit

Correct Answer is: a resistance is connected in series with armature

Q: 7. At the instant of starting when a D.C. motor is put on supply, it behaves like

Correct Answer is: a low resistance circuit

Q: 8. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of

Correct Answer is: D.C. series motor

Q: 12. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this

Correct Answer is: compound motor

Q: 13. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

Correct Answer is: series motor

1. A D.C. series motor is that which

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

2. A direct on line starter is used: for starting motors

iip to 5 H.P.
up to 10 H.P.
up to 15 H.P.
up to 20 H.P.

3. A three point starter is considered suitable for

shunt motors
shunt as well as compound motors
shunt, compound and series motors
all D.C. motors

4. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of

current in the conductor aovtaat of conductor
resultant force on conductor
none of the above

5. As -the load is increased the speed of D.C. shunt motor will

reduce slightly
increase slightly
increase proportionately
remains unchanged

6. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit

a resistance is connected in series with armature
a resistance is connected parallel to the armature
armature is temporarily open circuited
a high value resistor is connected across the field winding

7. At the instant of starting when a D.C. motor is put on supply, it behaves like

a highly resistive circuit
a low resistance circuit
a capacitive circuit
none of the above

8. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of

D.C. series motor
D.C. shunt motor
induction motor
all of above motors

9. By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?

Frame
Shaft
Commutator
Stator

10. D.C. generators are installed near the load centres to reduce

iron losses
line losses
sparking
corona losses

11. D.C. generators are normally designed for maximum efficiency around

full-load
rated r.p.m.
rated voltage
all of the above

12. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this

series motor
shunt motor
compound motor
any of the above

13. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

series motor
shunt motor
compound motor
any of the above

14. D.C. series motors are used

where load is constant
where load changes frequently
where constant operating speed is needed
in none of the above situations.

15. D.C. shunt motors are used for driving

trains
cranes
hoists
machine tools

16. Differentially compound D.C. motors can find applications requiring

high starting torque
low starting torque
variable speed
frequent on-off cycles

17. During rheostat braking of D.C. series motors

motor is run as a generator
motor is reversed in direction
motor is run at reduced speed

18. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be

level compounded
under compounded
cumulatively compounded
differentially compounded

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

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

20. For a D.C. shunt motor if the excitation is changed

torque will remain constant
torque will change but power will remain constant
torque and power both will change
torque, power and speed, all will change

21. For constant torque drive which speed control method is preferred ?

Field control
Armature voltage control
Shunt armature control
Mechanical loading system

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

it limits the speed of the motor
it limits the starting current to a safe value
it starts the motor
none of the above

23. For the same H.P. rating and full load speed, following motor has poor starting torque

shunt
series
differentially compounded
cumulativelycompounded

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

Low speed operation
High speed operation
Variable speed operation
Fixed speed operation

25. For which types of D.C. motor, dynamic braking is generally used ?

Shunt motors
Series motors
Compound motors
All of the above

26. Hopkinsons test on D.C. machines is conducted at

no-load
part load
full-load
overload

27. If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor

of lower H.P. should be selected
of higher H.P. should be selected
can be used for 50Â°C ambient temperature also
is to be derated by a factor recom-mended by manufacturer and select the next higher H.P. motor

28. If a D.C. motor is connected across the A.C. supply it will

run at normal speed
not run
run at lower speed
burn due to heat produced in the field winding by .eddy currents

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

Series motor
Shunt motor
Differentially compound motor
Cumulative compound motor

30. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

this will make armature to take heavy current, possibly burning it
this will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
nothing will happen to motor
motor will come to stop

DC Motors MCQ Multiple Choice Questions Answers for Practice

1. A D.C. series motor is that which

2. A direct on line starter is used: for starting motors

3. A three point starter is considered suitable for

4. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of

5. As -the load is increased the speed of D.C. shunt motor will

6. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit

7. At the instant of starting when a D.C. motor is put on supply, it behaves like

8. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of

9. By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?

10. D.C. generators are installed near the load centres to reduce

11. D.C. generators are normally designed for maximum efficiency around

12. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this

13. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

14. D.C. series motors are used

15. D.C. shunt motors are used for driving

16. Differentially compound D.C. motors can find applications requiring

17. During rheostat braking of D.C. series motors

18. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be

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

20. For a D.C. shunt motor if the excitation is changed

21. For constant torque drive which speed control method is preferred ?

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

23. For the same H.P. rating and full load speed, following motor has poor starting torque

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

25. For which types of D.C. motor, dynamic braking is generally used ?

26. Hopkinsons test on D.C. machines is conducted at

27. If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor

28. If a D.C. motor is connected across the A.C. supply it will

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

30. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

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DC Motors MCQ Multiple Choice Questions Answers for Practice

1. A D.C. series motor is that which

2. A direct on line starter is used: for starting motors

3. A three point starter is considered suitable for

4. According to Flemings left-hand rule, when the forefinger points in the direction of the field or flux, the middle finger will point in the direction of

5. As -the load is increased the speed of D.C. shunt motor will

6. As there is no back e.m.f. at the instant of starting a D.C. motor, in order to prevent a heavy current from flowing though the armature circuit

7. At the instant of starting when a D.C. motor is put on supply, it behaves like

8. Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of

9. By looking at which part of the motor, it can be easily confirmed that a particular motor is D.C. motor?

10. D.C. generators are installed near the load centres to reduce

11. D.C. generators are normally designed for maximum efficiency around

12. D.C. motor is to a drive a load which is almost nil for certain part of the load cycle and peak value for short duration. We will select this

13. D.C. motor is to drive a load which has certain minimum value for most of the time and some peak value for short duration. We will select the

14. D.C. series motors are used

15. D.C. shunt motors are used for driving

16. Differentially compound D.C. motors can find applications requiring

17. During rheostat braking of D.C. series motors

18. Flywheel is used with D.C. compound motor to reduce the peak demand by the motor, compound motor will have to be

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

20. For a D.C. shunt motor if the excitation is changed

21. For constant torque drive which speed control method is preferred ?

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

23. For the same H.P. rating and full load speed, following motor has poor starting torque

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

25. For which types of D.C. motor, dynamic braking is generally used ?

26. Hopkinsons test on D.C. machines is conducted at

27. If a D.C. motor designed for 40°C ambient temperature is to be used for 50°C ambient temperature, then the motor

28. If a D.C. motor is connected across the A.C. supply it will

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

30. If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens

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