Question

Question 17 (9 points) (a) Label the parts of the DC motor. (5 marks) 1 2 3 5 (b) Explain the Motor Principle in relation to the operation of the DC motor. ( marks) (c) Explain the role of the commutator in the DC motor. (2 marks)

Answer 1

a)

1. Copper Wire terminals.

2. Permanent magnet (north pole)

3. Commutator segments

4. Carbon Brush

5. Armature slot (rotor)

b)

Dc motor working principle is given by Lorentz Law, which states that “ when a the current-carrying conductor placed in a magnetic field it experiences a force” and hence experienced force is called the Lorentz force. Basically here permanent magnets will provide a constant magnetic field and current after entering through the brushes reverse its direction with the help of commutator which is commutation and this alternating current helps in producing unidirectional torque hence motor rotates.

c)

Commutator in DC machines helps in the process of commutation which is the process of reversing of current .

Hence in case of dc motors it converted dc into alternating current which is similar to the functional of inverter.