Explain the principle, construction, and working of an electric motor with the help of a labeled diagram. Also, state th

Question

Explain the principle, construction, and working of an electric motor with the help of a labeled diagram. Also, state the role of the split ring in an electric motor.

Accepted Answer

Principle of Electric Motor
An electric motor works on the magnetic effect of current. It is based on the principle that when a current-carrying rectangular coil is placed in a magnetic field, it experiences a force and rotates. The direction of rotation is given by Fleming's Left-Hand Rule. Construction Armature Coil (ABCD): An insulated copper wire wound around a soft iron core forming a rectangular loop. Strong Magnets (N and S): Permanent magnets that provide a strong magnetic field across the coil. Split Rings (Commutator - $R1, R2$): Two halves of a metallic ring that reverse the direction of current flowing through the coil every half rotation. Brushes ($B1, B2$): Two conducting carbon brushes that press against the split rings to provide electrical contact from the external battery. Battery: Source of direct current. Working When the key is closed, current flows from the battery through brush $B1$, split ring $R1$, coil ABCD, split ring $R2$, and brush $B2$. According to Fleming's Left-Hand Rule, arm AB experiences a downward force, while arm CD experiences an upward force. These equal and opposite forces create a turning couple (torque) that rotates the coil in a clockwise direction. After half a rotation, the positions of $R1$ and $R2$ interchange with the brushes. The current in arm AB now flows outwards (previously inwards), reversing the direction of current in both arms. Consequently, the arm that was pushed down is now pushed up, ensuring continuous rotation in the same direction. Role of Split Ring (Commutator)
The split ring acts as a current reverser. In an electric motor, the commutator reverses the direction of current in the coil after every half rotation, ensuring that the motor continues to rotate in the same direction continuously without stopping.

Magnetic Effects of Electric Current

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