Working of DC Motor, The field magnets are excited Developing Alternate N and S poles; The Armature Conductors carry current.

Working of DC Motor

When the Terminals of the motor are connected to an External source of dc supply then

(i) The field magnets are excited Developing Alternate N and S poles;

(ii) The Armature Conductors carry current.

All conductors under N-pole carry current in one direction while all the conductors under S-pole carry current in the opposite direction. Suppose the conductors under N-pole carry current into the plane of the paper. And those under S-pole carry current out of the plane of the paper as shown in Fig. Since each armature conductor is carrying current and is placed in the magnetic field, mechanical force acts on it.

It is evident that force on each conductor is tending to rotate the Armature in an Anticlockwise direction when Fleming’s left hand rule is applied. All of these forces combine to create a driving torque that causes the armature to begin rotating. When a conductor switches from one side of a brush to the other,. The current flowing through it is reversed, and at the same time, the next pole, which has the opposite polarity, begins to influence it. As a result, the conductor is still under the same force.