Question

Draw a labelled circuit diagram of a simple electric motor
and explain its working. In what way these simple electric
motors are different from commercial motors?​

Answer 1

Electric motor: A motor is a device which converts electrical energy into mechanical energy.

Principle of motor : A motor works on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it. A force acts on the coil which rotates it continuously.

When electric current is passed into the rectangular coil, this current produces a magnetic field around the coil.

The magnetic field of horse shoe-type magnet then interacts with the magnetic field of the coil and causes the coil to rotate continuously.

If ABCD is in horizontal position current from battery enters the coil through brush B _{ 1 }, and commutator half ring C:. The current flows in the direction ABCD

and leaves via ring and brush B _{ 2 }

The direction of current is from A to B, the direction of current is from C to D. The force on side AB of the coil is in the downward direction. Whereas the force on the side CD of the coil is in the upward direction. ABCD rotate in anti-clockwise direction.

While rotating when the coil reaches vertical position then the brushes B _{ 1 } and B _{ 2 } will touch the gap between the commutator rings and current to the coil is cut off. But the coil does not stop rotating because it has already gained momentum.

The coil CD comes on the left side and AB comes to the right side. Again they come in contact with brush B _{ 1 } Current direction is reversed.

The reversing of current in the coil is repeated after every half rotation due to which the coil continue to rotate as long as current from the batter is passed through it. The rotating shaft of electric motor can drive a large number of machines which are connected to it.

Mark me as brilliant

Answer 2

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Your diagram is on the attachment

It is a rotating device that converts Electrical Energy into Mechanical Energy.

$\huge\boxed{\red{Principle}}$

It is based on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it, two equal and opposite forces act on the coil which rotates it continuously.

$\huge\boxed{\orange{Working}}$

● Let coil ABCD be in horizontal position.

When the key is closed, current flows back to the battery through brush X and flows to the battery through The brush Y via ring R2

● No force acts on arms BC and AD as they are parallel to magnetic field. Arm AB experiences a force in downward direction and arm CD experiences an equal force in upward direction.

The direction of force is obtained by applying Fleming's left hand rule. This causes the coil to rotate in the anti-clockwise direction.

● When the coil rotates is in the vertical position, the brushes lose contact with the rings and current stops flowing.

But the coil does not stop due to inertia of motion.

● When the coil rotates, the rings change their positions and come in contact with opposite brushes.

This reverses the direction of current through the coil but the direction of current on right hand side of the coil remains the same.

●So, the force on right hand side is always upward and a force on left hand side is always in downward direction. Thus, the coil continues to rotate in anti-clockwise direction.

$\huge\boxed{\purple{Components}}$

The electric motor has the following components :

◇ An electromagnet instead of a permenant magnet.

◇ A large number of turns of conducting wire in the current carrying coil.

◇ A soft iron core.

Difference between Electric and commercial Motors

• The most obvious difference is the type of current eachmotor turns into energy, alternating current in the caseof AC motors, and direct current in the case of DCmotors.

• AC motors are known for their increased power output and efficiency, while DC motors are prized for their speed control and output range.

$\huge{\mathfrak{\orange{hope\; it\; helps}}}$