Introduction
An AC generator also called the Alternating Current Generator is a type of device that converts the mechanical energy that is present into alternating energy for daily use in various appliances. AC generators contain slip rings to produce alternating currents whereas DC generators tend to use direct current as the result of the DC generator. Bicycles, electric scooters, microwaves, and sailboats all use the AC generator to produce AC current. Mechanical energy is provided by steam and gas turbines as well as internal combustion engines to the AC generators. These are also highly useful in wind turbines and small hydropower plants in order to convert the high-pressure gas streams to lower pressure zones. Students can hence now know more regarding the AC Generator - Principle, Parts, Uses and Working through Vedantu.
AC Generator - Principle, Parts, Uses and Working
The machine that transforms mechanical energy into electrical energy is known as an Electrical generator. The generator is usually classified into type based on the supply of power, namely AC and DC. For the DC generator, the supply to the machine is single directional, and the vice versa is applicable for the AC generator. With this difference in input supply, the internal operation differs for the generators.
AC Generator, its construction, how EMF is induced, its parts and applications, and more will be discussed here in this article. Slip rings are used in AC for the generation of the alternating current in the machine. The generated voltage or current is initially alternating one in both the kinds of the generator.
AC Generator Definition
The machine which converts the mechanical energy into electrical energy in the output of alternating current or voltage is known as AC Generator. The machine works on Faraday's law of Electromagnetic induction. Here, the Direct Current voltage is made to rotate inside the fixed coil, like a huge power generator that produces the AC current.
By using Fleming's right-hand rule, the direction of the alternating current in the generator is determined. The below diagram shows the four-pole single-phase generator:
Circuit Diagram AC Generator
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What are the Parts of an AC Generator?
Here is the list of the parts of the AC generator, which mainly consists of the yoke, permanent magnets, coils or loop wound with wires, pole core, armature core, pole shoe, slip rings, and brushes. The frame acting as the protecting cover of the generator is known as a yoke. All the components mentioned above are within the yoke. The magnets generate the magnetic field between the air gaps. The coil made up of four-wire AB, BC, CD, and DC is placed inside the magnetic field. The schematic diagram of the AC generator is shown below with all the labels for your understanding.
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The pole shoe is within the pole core to house the windings—the armature windings placed in the armature core. The armature flux results in the production of the armature core. The operation is conducted smoothly, with the use of slip rings. The rings are attached to the brush through which the current passes. As the slip rings pass smoothly through the brushes, it avoids the twisting of the wires.
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Working of AC Generator
The principle of Faraday's law of electromagnetic induction is followed for the working of the AC generator.
An EMF is induced whenever a conductor cuts the lines of magnetic flux, which causes the current to pass through the conductors. For a better insight into the mechanism of an AC Generator, let's consider a simple loop generator which is placed under the influence of a magnetic field.
Name the loop placed in the magnetic field named ABCD; as mentioned earlier, the loop of wire is named as AB, BC, CD, and DC. With the help of an external shaft which acts as the primary mover, the loop is rotated. In the below diagram, it shows the working of the AC generator.
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The magnetic flux lines will move from left to right and from north pole to south pole. With the help of the shaft, the loop is rotated as it cuts the magnetic flux. This develops the EMF, which causes the current to flow through the conductors. With the help of Fleming's right-hand rule in generators, the direction of the current is determined.
As per Fleming's right-hand rule, the middle finger, forefinger and thumb are positioned perpendicular to each other, which is shown in the figure below.
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As per the diagram below, the loop rotates; the rule determines the direction of the current inside the wire AB. For a half cycle, the current flows inside the wire AB. With the rotation of the loop, the current inside the wire AB reverses for the other cycle. The same procedure is performed for the other wires, i.e., in BC, CD, and DC, as the loop rotates the direction of the current changes for every half cycle. The figure shown below considers the above two cases for the working of the AC generator.
The slip rings are attached to the loop end and are responsible for the movement of the wires when the loop is rotated. The current passes through the slip ring to the brushes and then to load as it passes smoothly the slip rings through the brushes.
For every half-cycle of the loop, the direction of the current gets changed. By using a galvanometer, we can observe the alternating current at the load end. This is how the Alternating Current Generator generates an alternating voltage or current.
The Bottom Line!
From the above article, we had an overview of the Alternating Current Generator. The device converts the mechanical energy into electrical energy and gives an output of alternating current or voltage. Apart from that, the above article gives you insight into the working parts, uses, and their application in daily life.
FAQs on AC Generator
1.What is a 3-phase AC generator?
In an asymmetric three-phase power supply system there is a presence of three conductors that carry alternating current each of the same frequency and voltage amplitude which will be relative to the common reference but has a phase difference of one-third the period. The most commonly used reference is the one that connects to the ground and will often be a current-carrying conductor that will have no net current in it. Due to the phase difference that arises the voltage on any conductor tends to reach its peak when one-third of a cycle after one of the other conductors and one-third of the cycle before the remaining conductor. This delay in phase provides a constant power transfer to a balanced linear load. It also tends to make it possible to generate a rotating magnetic field that is present in an electric motor and hence generate another phase arrangement while using the transformers.
2.What is the emf induced in an AC generator?
If a coil of N turns and area A has been rotated at v revolutions per second in a uniformly present magnetic field then the motional emf that is produced will be given as follows:
E = NBA (2πv) sin(2πv) t
Where we assume that there at time t = 0 the coil will stay perpendicular to the field. The direction of this induced emf will be provided by Fleming’s rule or by Lenz’s law. Fleming’s first-hand rule states that when you stretch the forefinger, the middle finger, and the thumb of the right hand in such a way that they are perpendicular to each other then the forefinger will indicate the direction of the magnetic field, the thumb will indicate the direction of the motion of the conductor and the middle finger will indicate the induced current present in the conductor.
3.What are the advantages of an AC generator over a DC generator?
There are a few advantages of AC generator over the DC generator and can be provided as follows:
AC generators can be easily increased or decreased with the help of transformers.
Due to the step-up feature of the AC generators, it is seen that the transmission link size is smaller in the AC generator than what is observed in the DC generator.
The loss observed in the AC generator is much lower than what is observed in the DC machine.
The size of an AC generator will always be smaller than a DC generator hence it needs much smaller space as compared to a DC generator.
4.What is the process involved in the generation of electricity via an AC generator?
AC generators work on the principle of Faraday’s law of electromagnetic induction. It is seen that when the armature rotates between the two magnetic opposite poles on an axis that is perpendicular to the magnetic field the flux linkage of the armature tends to change continuously. Due to this change that occurs over continuously, there is an emf that is induced in the armature. As a result, the electric current flows through the galvanometer and the slip rings and brushes.
5.How is AC Generator - Principle, Parts, Uses, and Working an important topic and why is it important for students to know more about it?
The topic AC Generator - Principle, Parts, Uses and Working is one of the most important topics that are present in Physics. This topic needs students to have a strong foundation along with a piece of sound knowledge in the field of Physics. This is hence a topic of much importance. It is also one of the most widely used appliances in the house and hence it is needed that students would be aware of the generators. By learning about the theory of the AC generators it is possible to know more about its applications in real life. Students can also take a look at the Vedantu NCERT Solutions for Physics to know more about the AC Generator - Principle, Parts, Uses, and Working.
6.What is the Principle of the AC Generator?
On the principle of Faraday's law of electromagnetic induction, the AC generator works.
The diagram above shows the simple working of an AC generator. As shown in the figure, as the coil rotates, it experiences a change in the magnetic flux. According to Faraday's law of electromagnetic induction, the electrons are moved by the EMF induced in the coil which causes the generation of an electric current. The circuit is closed through the load (lamp), where the current generated is alternating in nature as the flux is alternating in nature.
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As shown in the figure, the rotating coil is known as rotor, and field poles as stator.
But in practice, AC generators or alternators are constructed in such a way that the rotating part (rotor) is a magnetic field. In contrast, the coil is stationary (stator) of the machine.
7.What are the Uses of the AC Generator?
The Uses of AC Generators are a Pervasive Component in Many Applications Such as,
In automobiles, where they are known as alternators
power generation from windmills
power generation from hydro-electric dams
AC Generators have Many Significant Advantages over DC Generators:
The design is simple.
The maintenance cost is low.
Losses are less
The size of the equipment is compatible.
AC generators are cheaper to manufacture
It is easy to step up and step down the power generated by the AC generator with the help of the transformers
These are the explanations that AC generators are the leading technology in most applications.