Question

Explain structure and working of electric motor,and on what principle is it based on?​

Answer 1

Answer:

Electric Motor

Electric motor is a device that converts electrical energy to mechanical energy.

Parts of a Electric Motor

Insulated Copper wire: A rectangular coil of wire ABCD

Magnet Poles: A magnet as placed above ie North Pole and South Pole. This creates a magnetic field as shown above.

Split Rings: Two disjoint C-shaped rings P and Q. It acts as a commutator (which can reverse the direction of current)

Axle: The split rings are placed on the axle which can rotate freely.

Brushes: The outside of the split rings are connected to conducting brushes X and Y.

Source Battery: To source current.

Working

When the current begins to flow, current flows through brush X, then A to B, B to C, C to D and then to brush Y and into the battery.

Now applying Fleming's Left Hand Rule to wire AB, Current is along AB, Magnetic Field is as shown (North-> South), the motion of the wire is downwards.

Now applying Fleming's Left Hand Rule to wire CD, Current is along CD, Magnetic Field is as shown (North-> South), the motion of the wire is upwards.

The rectangular coil begins to move in the anti-clockwise direction

Note that during anti-clockwise motion, the split rings and axle also move, whereas the brushes don't move.

After half a rotation, Wire CD and Split ring Q moves to the left.  Wire AB and Split ring P moves to right. Brushes X and Y donot move.

Now applying Fleming's Left Hand Rule to wire CD, Current is along DC. (Battery -> Split ring Q -> DC , Magnetic Field is as shown (North-> South), the motion of the wire is downwards.

Now applying Fleming's Left Hand Rule to wire AB, Current is along BA. (Battery -> Split ring Q -> DC --> CB -> BA --> Split ring P) , Magnetic Field is as shown (North-> South), the motion of the wire is upwards.

So, again the coil rotates in the anti-clockwise direction.

The reversal of current in the coil results in the continous rotation of the coil. The reversal of current is achieved by the commutator rings

Applications

Electric Fans

Refrigerators

Mixers

Washing machines

Explanation: