Electrical energy is the main source of all kinds of development. Electricity is used in lights, fans, televisions, refrigerators, various industrial plants, transportation systems, etc. Fan, refrigerators, television, etc. are all machines. A machine is a mechanical object that is made up of a combination of different parts to perform a specific task. The machine can be electrical or mechanical. An electric machine is a mechanical method that converts electrical energy into mechanical energy or mechanical energy into electric energy. Like televisions, fans, refrigerators, transformers, etc. generators are also a type of machine (2). This article will explain how do electric generators work? and types of electric generator and differences.
An electric generator is a type of electrical device that converts mechanical energy or power into electrical energy or power. Electric generators use the law of dynamic electromagnetic power generation to bring about this transformation.
According to Faraday’s electromagnetic law, when a conductor passes through a magnetic flux, a dynamic electromagnetic induction is created in it. When a conductive substance is inserted into a closed circuit, an electric current is obtained due to this flux thus creating electricity.
History of making electric generators
Scientists use static electric generators for their high voltage requirements in early times. Before the relationship between electricity and magnetism was discovered, generators were built on the law of static electricity. The British scientist James Wilmshurst created such a static electrical device.
People have known the use of static electricity since ancient times. But in the eighteen century, the British scientist Michael Faraday discovered the potential difference between the two ends of a moving electrode along a perpendicular with a magnetic field. This is called Faraday’s electromagnetic law. Based on this law, Faraday was the first to build an electric generator. This generator is capable of generating electricity.
Dynamo (1832) were first made using Faraday’s law. The device was made by French equipment manufacturer Hippolyta pixie. This is the first electric generator capable of supplying electricity to industrial plants. Using Faraday’s law, the dynamo converts mechanical energy into a vibrating one-way electric current (2).
Types of electric generator
There are two types of electric generator mainly AC generators and DC generators.
1. AC generator
An AC generator is a type of generator that produces variable voltage. AC generators are made based on the theory of electromagnetic induction. These generators required magnetic fields and armatures to generate variable voltages. It is a device through which mechanical energy can be converted into electrical energy. This device is also called an alternator (4).
Structure of AC generator
Currently, AC generators are the most used in daily life. The AC generator has a field magnet and a rectangular coil of wire on a raw iron sheet in the middle of the magnet. The raw iron plate here is called an armature. The armature is mechanically rotated at a speed between the two poles of the magnet. The two ends of the rectangular coil are connected by two slip rings. The slip ring can rotate along the same axis of the two armatures. The two carbon brushes are placed in such a way that they touch the slip ring when the armature is rotating. External resistors are attached to both brushes (1) & (5).
The function of the AC generator
When the armature is rotated the armature coil intersects the ball lines of the magnetic field. According to the law of electromagnetic induction, an electric current is absorbed in the coil and a periodic electric current is generated in the circuit to keep the two ends of the coil connected to the outer circuit. The direction of the induced electric current also changes one time in one rotation of the coil. In this way, electric energy is generated from the mechanical energy of the electric generator. The direction of the induced current can be identified using Fleming’s right-hand law (5).
Type of AC generator
There are two types of AC generators (5).
1. Induction generator
An induction generator is an alternating current generator just like a normal generator. This generator works in the same way as a normal generator. The function of this generator is similar to that of a transformer. The only difference is that the transformer is a static device and this generator is a rotating device. These are used in small machines such as mixers.
2. Synchronous generator
The Synchronous generator operates according to Faraday’s law of electromagnetic induction. This generator is an alternating current generator that rotates at synchronous speed. These are used in power plants because of their high efficiency.
2. DC generator
Dc generator is a direct current generator. It acts as a kind of electrical machine that converts mechanical energy into direct current. This generator is made based on Faraday’s electromagnetic law (1).
Structure of DC generator
DC generators consist of different parts. The various parts of this generator are yoke, poles, pole shoes, field winding, rotor or armature core, stator, armature winding, commutator, and brushes. The stator is an important part of a DC generator. The stator provides the magnetic field where the coils rotate. Rotor or armature core is the second part of this generator. The rotor of a DC generator consists of socketed iron layers. These layers are equipped to shape a cylindrical armature core. The outer covering of the generator is called the yoke. It is made of cast iron or steel. The poles are attached to the yoke. Field windings are made of copper. The field winding is twisted with the pole. Armature winding is a spiral copper coil that stays in the armature slot. Armature conductors are insulated from one another and also separate from the armature core. Pole shoes are used to spread the magnetic flux so that the field coil does not fall. The commutator is cylindrical in shape. The commutator stores the current. The brush is used to supply contacts. And the output is supplied from here (5).
The function of the DC generator
When the armature located in the static magnetic field of a DC generator is rotated, its coil cuts the magnet flux. As a result, AC voltage is generated according to Faraday’s electromagnetic law in the coil. The generated voltage is converted to DC voltage by a commuter connected to the armature and transmitted to the external circuit. This is how a DC generator works (1) & (5).
Type of DC generator
There are two types of DC generators.
In this type of generator, the field coils are powered by the current generated from the generator. Self-excited generators are of three types. These are series generator, shunt generator, compound generator.
2. Separately excited
In this type of generator, the field coils are energized from an independent external DC source.
The work of the electric generator
The generator does not actually generate electricity. The electric generator converts mechanical energy or power into electric energy. They capture the kinetic energy and convert it into electrical energy by forcing electricity from an external source through an electrical circuit. When the armature is rotated the armature coil intersects the ball lines of the magnetic field. According to the law of electromagnetic induction, an electric current is absorbed in the coil and a periodic electric current is generated in the circuit to keep the two ends of the coil connected to the outer circuit. The value of this induced electric current usually depends on the magnitude of the magnetic field and the speed of rotation. The direction of the induced electric current also changes one time in one rotation of the coil. Thus electric energy is generated from the mechanical energy of the electric generator (5).
Uses of electric generator
Nowadays, the use of generators is widespread. Because it is not yet possible to produce electricity as per the demand in our country. So many people are becoming dependent on generators. Electric generators are most commonly used, especially in small and large industrial plants. Electric generators are also used in various education in various educational institutions, offices, courts. Hospitals and various occasions. Many people also use mini generators to meet the constant demand for electricity in their homes (2) & (5).