8/2/2019 Assign 4 DC Motor

1/4

UniKL-MIAT Sdn. Bhd.

Name : .......Class : .... Date :

Assignment # 4

1. Motor is a machine which convert ______________________ energy to

_____________________ energy.

02. _____________________________ rule is used to determine direction of acurrent carrying conductor moves within a magnetic field.

03. The amount of force that provide by DC motor depends on

a. _______________________________________________________

b. _______________________________________________________

c. _______________________________________________________

04. In D.C. motor, when the armature turn within the magnetic field, induce e.m.f.

occur on the armature (generator action) is known as _________________ e.m.f.

05. Name three types of DC motor:

a. ______________________________________________

b. ______________________________________________

c. ______________________________________________

06. A _________________ wound DC motor is often used as a starter because of high

starting torque characteristic and it must be start _____________ load.

07. A motor that must be start off load is a ______________ wound motor due to low

starting torque characteristic.

08. To reverse direction of rotation of DC motor is by reversing the polarity to its

______________________ or ______________________

09. The back emf induced on the armature is maximum when the armature rotate at

___________________________ speed.

10. Name two losses in DC motor :

a. _________________________________________

b. _________________________________________

1mazlan/elect fund ii

8/2/2019 Assign 4 DC Motor

2/4

11. The effect of changing current to its field and armature simultaneously will cause

the motor to rotate in ______________________ direction.

12. The reason of inserting a starter resistance in series with the armature is to

______________________ the starting current during initial start.

13. The force that produce by a magnetic interaction between the two field (armature

and stator) is known as _________________________

14. The armature iron core being laminated, this is to reduce ____________________

15. The induce back emf is such that it always opposes the applied emf is known as

________________ Law.

16. Initial starting current of DC motor is very high due to no ______________ e.m.f.

17. A motor that can be rotate in both direction is known as _____________________

____________________ motor.

18. The field current (IF) is the same as current flow to the armature (IA). This

statement refer to _____________________ wound motor.

19. A shunt motor has _____________ turns of ________________ copper wire and

has very _____________ resistance.

20. A motor which has a series field and shunt field together is known as a

______________________ motor.

21. The armature current in dc motor is automatically control by the present of

____________________ emf.

22. Back emf is always _________________ than the applied emf.

2mazlan/elect fund ii

8/2/2019 Assign 4 DC Motor

3/4

Answers

Assignment # 4

1. Motor is a machine which convert electrical energy to mechanical energy.

02. Flemings Hand rule is used to determine direction of a current carrying

conductor moves within a magnetic field.

03. The amount of force that provide by DC motor depends on

a. Strength of magnetic field

b. Amount of current flow in a conductor

c. Length of conductor

04. In D.C. motor, when the armature turn within the magnetic field, induce e.m.f.

occur on the armature (generator action) is known as back e.m.f.

05. Name three types of DC motor:

a. Series motor

b. Shunt motor

c. Compound motor

06. A series wound DC motor is often used as a starter because of high starting torque

characteristic and it must be start ON load.

07. A motor that must be start off load is a shunt wound motor due to low starting

torque characteristic.

08. To reverse direction of rotation of DC motor is by reversing the polarity to its

field or armature

09. The back emf induced on the armature is maximum when the armature rotate at

higher speed.

10. Name two losses in DC motor :a. Copper losses

b. Iron losses

3mazlan/elect fund ii

8/2/2019 Assign 4 DC Motor

4/4

11. The effect of changing current to its field and armature simultaneously will cause

the motor to rotate in same direction.

12. The reason of inserting a starter resistance in series with the armature is to

limit/reduce the starting current during initial start.

13. The force that produce by a magnetic interaction between the two field (armature

and stator) is known as Torque

14. The armature iron core being laminated, this is to reduce eddy current

15. The induce back emf is such that it always opposes the applied emf is known as

Lenzs Law.

16. Initial starting current of DC motor is very high due to no back e.m.f.

17. A motor that can be rotate in both direction is known as split field series

motor.

18. The field current (IF) is the same as current flow to the armature (IA). This

statement refer to series wound motor.

19. A shunt motor has many turns of thin copper wire and has very high resistance.

20. A motor which has a series field and shunt field together is known as a

compound motor.

21. The armature current in dc motor is automatically control by the present of

back emf.

22. Back emf is always less than the applied emf.

4mazlan/elect fund ii