Introduction to Electric Generator
As the name itself suggests, an electric generator generates electricity. The electric generator or an AC electric generator is a device that converts mechanical energy to electrical energy in the form of current or alternating emf. In other words, the electric generator converts its kinetic energy into potential difference without violating the law of conservation of energy. Electric generators work on the principle of Electromagnetic induction.
Depending upon the type of electricity produced the electric generator is classified into AC generator and the DC generator. The electric generators are mainly used to provide power supply to domestic lines, industrial purposes, and commercial factories.
Physics as a subject is very interesting and mesmerizing at the same time. The subject correlates with other subjects like mathematics and chemistry. Your learnings should not only be confined to examination purposes and thus we aim at making it more interesting and fun. In this particular article, we shall discuss one such important concept of Physics and try to make the most out of the topic.
We shall be learning the following from the particular article -
Electric generator - An introduction
Working of an electric generator
Components of an electric generator
Important facts
Frequently asked questions
Explain the Working of Electric Generator
Before getting started with the working of an electric generator, let us first study the components of an electric generator.
Components of an Electric Generator
The schematic representation of an electric generator is as shown below. The construction of a generator is identical to the electric motor only difference being instead of a battery a galvanometer is used. The galvanometer is a device used for detecting the presence of electricity.
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The Electric Generator Consists of the Following Components
A rectangular wireframe or a rectangular coil, which is connected to the brushes.
Two strong magnets can be any kind like horseshoe magnets, a bar magnet, etc.
The ends of the coils are connected to the rings as shown in the diagram. The edges of the rings are further connected to brushes.
To detect the electricity a galvanometer is used.
As technology improves, an electric generator has its advancement and is widely used. An actual generator used for domestic purposes or industrial lanes it will consist of the following components:
An engine is used as a source of mechanical energy.
A lubrication system
A Fuel System
A Voltage Regulator
An Exhaust system
A charger
Main Control
Working of An Electric Generator
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Now let us understand what is the working of the generator. A rectangular coil is placed between the two magnets. Let us assume that we are rotating the coil in a clockwise direction with the help of axles connected to the rings.
On rotating the coil in a clockwise direction AB arm will move upwards and the CD arm will move downwards. We can apply Fleming’s Right-hand rule to the AB arm and the current flows from A to B. Similarly, we use Fleming’s Left-hand rule to the CD arm and we note that current flows from C to D. Hence the current will flow from B2 to B1.
Now after half rotation we see that CD will be on the left side and AB arm on the right side. Now, applying Fleming’s right-hand rule to the CD arm, results in the current flowing from C to D, and using Fleming’s left-hand rule for the AB arm, the resulting current flows from A to B. Hence the current will enter B1 and flow through B2.
Thus the direction of current changes after every rotation resulting in producing the altering current. Hence the electric generator generally is also known as the AC generator. If we want to produce DC, we will place a commutator between the rings.
This is the explanation for the construction and working of an electric generator. The above concept explains the electric generator in detail. If the question demands the construction of an AC electric generator we can give the same explanation.
Did You Know?
The first electric generator developed was back in 1660. Back in time, Otto invented a device that generated electricity due to friction. It was termed static electricity.
The credit for the invention of electric generators goes to Micheal Faraday.
He invented an electric generator as an application of his electromagnetic induction theory. He gave a simple experimental demonstration using a large horseshoe magnet and coil.
Due to generators even during power cuts, we can do our daily routines without interruption.
FAQs on Electric Generator
1. What is an electric generator?
An electric generator is a device that converts mechanical energy (the energy of motion) into electrical energy in the form of an electric current. It does not create energy but rather transforms it from one form to another, operating on the principle of electromagnetic induction and adhering to the law of conservation of energy.
2. What is the working principle of an electric generator?
An electric generator works on the principle of electromagnetic induction. This principle, established by Michael Faraday, states that when a conductor, such as a wire coil, is moved through a magnetic field, an electromotive force (voltage) is induced across the conductor. This induced voltage drives the flow of electric current.
3. How does an electric generator work?
An electric generator functions by rotating a coil of wire (armature) within a magnetic field created by strong magnets. As the coil spins, it cuts through the magnetic field lines, causing a change in the magnetic flux. According to Faraday's law of induction, this change induces an electric current in the coil. The direction of this current is determined by Fleming's Right-Hand Rule. This current is then collected by brushes and sent to an external circuit.
4. What are the main components of a simple electric generator?
A simple electric generator, as per the CBSE 2025-26 syllabus, consists of four main components:
- Armature: A rectangular coil of insulated copper wire that rotates within the magnetic field.
- Field Magnet: A strong magnet (permanent or electromagnet) that produces a uniform magnetic field.
- Rings: These can be either slip rings for an AC generator or a split-ring commutator for a DC generator. They facilitate the transfer of current from the rotating armature.
- Brushes: Conductive carbon or metallic blocks that press against the rings to collect the current and deliver it to the external circuit.
5. What are the different types of electric generators?
Based on the type of electrical current they produce, electric generators are primarily categorised into two types:
- AC (Alternating Current) Generator: Produces a current that periodically reverses its direction. It uses two continuous slip rings to maintain the alternating nature of the induced current in the external circuit.
- DC (Direct Current) Generator: Produces a current that flows in only one direction. It uses a split-ring commutator, which reverses the current's direction every half rotation, resulting in a unidirectional current flow in the external circuit.
6. What are the real-world applications and importance of an electric generator?
Electric generators are fundamentally important for modern society. Key applications include:
- Power Plants: They form the core of large-scale power stations (hydroelectric, thermal, nuclear) that supply electricity to the power grid.
- Backup Power: They provide an uninterrupted power supply to hospitals, homes, and businesses during power outages.
- Remote Locations: They supply electricity to areas not connected to the main power grid, such as remote villages, construction sites, and for outdoor events.
7. Why is a strong magnet an essential component in an electric generator?
A strong magnet is essential because the amount of electricity generated is directly proportional to the strength of the magnetic field. A stronger magnet creates a denser magnetic field, which means the rotating coil cuts more magnetic field lines in a given amount of time. This induces a larger electromotive force (EMF) and a stronger electric current. Without a magnetic field, the phenomenon of electromagnetic induction cannot occur.
8. How is an electric generator different from an electric motor?
Although they share a similar construction, a generator and a motor perform opposite functions:
- Energy Conversion: A generator converts mechanical energy into electrical energy. Conversely, a motor converts electrical energy into mechanical energy (motion).
- Operating Principle: A generator operates on electromagnetic induction (Fleming's Right-Hand Rule), while a motor operates on the principle that a force acts on a current-carrying conductor in a magnetic field (Fleming's Left-Hand Rule).
- Function: In simple terms, you spin a generator to get electricity, whereas you supply electricity to a motor to make it spin.
9. Can an electric generator create energy from nothing? Explain with respect to the law of conservation of energy.
No, an electric generator cannot create energy from nothing. It must strictly follow the law of conservation of energy, which states that energy can only be transformed from one form to another. A generator is an energy converter, taking an input of mechanical energy (from a source like a turbine) and transforming it into electrical energy. The electrical energy output is always less than the mechanical energy input due to energy losses, primarily as heat from resistance.
10. What is the role of split-ring commutators in a DC generator compared to slip rings in an AC generator?
The type of ring system used is the key structural difference that determines the output current:
- Slip Rings (AC Generator): An AC generator uses two separate, complete rings. Each end of the armature coil is connected to one ring. This setup allows the naturally alternating current induced in the rotating coil to be transferred directly to the external circuit.
- Split-Ring Commutator (DC Generator): A DC generator uses a single ring split into two insulated halves. The commutator reverses the connection to the brushes every half rotation. This action effectively rectifies the current, ensuring that while the current in the armature coil is alternating, the current flowing into the external circuit is always in a single direction (direct current).
