AC Generator

We have already studied the definition of the AC generator in class X, but there we will study the brief definition, principle, concept, working, and uses of the AC generator. We have studied that an AC generator is a device that converts mechanical energy to electrical energy. Here we are going to study its working, principle, and parts. 

Explain AC generator

AC generators are electric generators that convert/change mechanical energy to electrical energy in an alternating EMF or alternating current. In AC generators the supply of input is a mechanical energy switch supplied through combustion engines, gas turbines, and steam turbines. The generated output is alternating electrical power in the form of current and alternating voltage.

The working principle of the AC generator is based on Faraday’s Law of electromagnetic induction. The law states that the current will be induced in the conductor when placed in the magnetic field.

AC Generator Principle, Parts and  Working

The different components of an AC generator are mentioned below:-

• Field
• Slip Rings
• Rotor
• Stator
• Prime Mover
• Armature

The AC generator consists of the components listed above. So, lets us discuss the working of each part briefly:-

• Field: This element of the AC generator comprises the conductor’s coils that receive the voltage from source & create magnetic flux. Magnetic flux in the magnetic field steps down the armature to generate voltage. It is the output voltage of the AC generator. 
• Armature: An Armature is a rectangular coil with many turn wounds around a soft iron core, a shaft it can be rotated rapidly. The voltage is generated in this part of the AC generator. This component comprises coils of wires which are huge enough to transfer the full-load current of the generator.
• Field Magnet: A field magnet is a permanent solid magnet with concave poles. It has two slip rings S1 and S2, connected to the armature and thus rotate with it. Two Brushes B1 and B2 provide electrical contact with the slip ring and load, which may be a Galvanometer and shore.
• Prime Mover: It is the part used to operate the AC generator is known as the prime mover. The prime mover could either be a steam turbine, a motor, or a diesel engine.
• Rotor: Roter is the rotating module of a generator. It is one of the essential components to move the generator primarily. 
• Stator: The stationary part of an AC generator is known as Stator. The stator consists of a lamination of alloys, magnetic iron or steel to expand the loss of eddy current.
• Slip Rings: Slip rings are electrical connectors that transport electricity from and to an AC generator’s rotor. They are primarily used to transfer current from a fixed device to a revolving one.

AC Generator- Working Principle

An AC generator works on the principle of electromagnetic induction. In electromagnetic induction, an electric current or EMF is induced in the coil when there is a relative motion between a coil and a magnetic field. 

The magnetic flux associated with an armature changes continually as it rotates between the poles of the field magnet. As a result, the armature generates an EMF. As a result, an electric current flows through the armature and galvanometer, and the slip rings and brushes note that the galvanometer needle swings between negative and positive values, indicating that the galvanometer is receiving alternating current (AC).

The Direction of Electric Current

The armature ABCD is initially vertical, with its side (AB) up and another side (CD) down. The direction of the magnetic field is from left to right as the armature undergoes half rotation clockwise; one arm moves down while the other moves up. According to Fleming’s Right Hand Rule, the current will flow in the direction of DCBA. So, the current will flow from B1 to B2 through the Galvanometer during the next half rotation; arm AB moves up while arm CD moves down. Again from Fleming’s Right Hand Rule, current will flow in the direction of ABCD, from B2 to B1 bond through the galvanometer. Thus, the induced current will change its direction in every half rotation.   

Direct Current electric generator

A direct current generator or DC generator is a device that converts chemical or mechanical energy into direct current electricity. The electricity produced by this device is dynamic and has no up and down peaks like an AC generator.

Benefits of the AC Generator over the DC Generator

AC generators have numerous benefits over DC generators. Some significant advantage of AC generator over DC generator is as follows:-

• The AC is simpler to generate than DC. AC is more cost-efficient than DC
• In AC generators, during the generation of Power, energy wastage is almost negligible.
• The Size of the AC generator is smaller as compared to DC.
• AC is easy to step up and step down through the transformer. 
• Transmission link size in AC generator is thinner due to step-up future.
• AC generator is cheaper than DC.

Uses of the AC Generator 

An AC generator is one of the significant energy-generating components of many electric devices we use in our daily lives. Some of the appliances are as follows:-

• They work as alternators in automobile devices. 
• They work as power generators in a windmill.
• They work as power generators in Hydroelectric dams.

Conclusion

So, in this chapter, we learned that an AC generator is a device that converts mechanical energy into electrical energy in the form of alternating EMF or alternating current. It is based on the principle of electromagnetic induction. In AC generators the supply of mechanical energy is supplied by combustion engines, gas turbines, and steam turbines.  The working principle of the AC generator is based on Faraday’s Law of electromagnetic induction. The law states that the current will be induced in the conductor when placed in the magnetic field.  AC generators have many uses in your day-to-day life.  It is observed that this particular topic carries five marker questions in the CBSE Board examination.