What is an Electric Generator and Its Working

The electric generator was invented before the correlation between electricity as well as magnetism was discovered. These generators use electrostatic principles to operate with the help of plates, moving belts which are charged electrically as well as disks to carry charge toward an electrode with high potential. Generators use two mechanisms to generate the charge like the triboelectric effect otherwise electrostatic induction. So, it generates low current as well as very high voltage due to the complexity of insulating machines as well as their inefficiency. The power ratings of Electrostatic generators are low so they never utilized for electrical power generation. The practical applications of this generator are to supply power to X-ray Tubes as well as in atomic particle accelerators.

What is an Electric Generator?

An alternate name of an electric generator is a dynamo for transmission as well as the distribution of energy over power lines to different applications like domestic, industrial, commercial, etc. These are also applicable in aircraft, automobiles, trains, ships for generating electrical power. For an electrical generator, the mechanical power can be obtained through a rotary shaft that is equivalent to the shaft torque which is multiplied by using angular or rotational velocity.


The mechanical energy can be obtained through different sources like hydraulic turbines at waterfalls/dams; steam turbines, gas turbines, and wind turbines, where steam can be generated through heat from the ignition of fossil fuels otherwise from nuclear fission. Gas turbines can burn the gas directly within the turbine otherwise diesel engines & gasoline. The generator construction as well as its speed may change based on the mechanical prime mover’s characteristics.

A generator is a machine that converts mechanical energy into electrical energy. It works based on the principle of the faraday law of electromagnetic induction. The faradays law states that whenever a conductor is placed in a varying magnetic field, EMF is induced and this induced EMF is equal to the rate of change of flux linkages. This EMF can be generated when there is either relative space or relative time variation between the conductor and the magnetic field. So the important elements of a generator are:

  • Magnetic field
  • The motion of the conductor in a magnetic field

Features

The main features of the electric generators include the following.

Power


The power output capacity of an electric generator is a wide range. By selecting an ideal generator, high and low power requirements can be easily met through identical output power.

Fuel

Several fuel options like petrol, diesel, LPG, natural gas are accessible for electric generators.

Portability

Electrical generators are portable because they designed with handles and wheels. So, they can be easily moved from one location to another.

Noise

Some generators include noise reduction technology so that noise pollution can be reduced.

Construction of Electric Generator

The construction of an electric generator can be done using different parts like alternator, fuel system, voltage regulator, cooling & exhausts system, lubrication system, battery charger, control panel, frame or main assembly.

Alternator

The conversion of energy that occurs in a generator is known as an alternator. This includes both stationary as well as moving parts which work jointly to generate the electromagnetic field as well as electrons flow to generate electricity.

Fuel System

The fuel system in the generator is used to generate the required energy. This system comprises a fuel pump, fuel tank, a return pipe, and a pipe that is used for connecting the engine and tank. A fuel filter is used to eliminate debris before it reaches the engine & an injector makes the fuel to flow into the combustion chamber.

Engine

The main function of the engine is to supply electrical energy to the generator. The range of power generated by a generator can be decided through the power of the engine.

Voltage Regulator

This component is used to control the voltage of the electricity that is generated. It also converts the AC electricity to DC if required.

Cooling & Exhaust Systems

Generally, generators produce a lot of heat so reduce the heat from the overheat of a machine, the cooling system is used. The exhaust system is used to eliminate the fumes during its operation.

Lubrication System

In a generator, there are several small as well as moving parts which are necessary to lubricate them sufficiently using engine oil so that smooth operation can be obtained as well as it protects from surplus wear. The levels of lubricant should be checked frequently for every 8 hours of the process.

Battery Charger

Batteries are mainly used to provide power to the generator. It is a complete automatic component used to make sure the battery is prepared to go once necessary by supplying it using a stable low-level voltage.

Control Panel

The control panel is used to control every feature of the generator while operating from beginning to end. Modern units are capable of sensing when the generator turns ON/OFF automatically.

Frame/Main Assembly

The frame is the body of the generator & it is the part where the structure holds it all in place.

Working of Electric Generator

Generators are basically coils of electric conductors, normally copper wire, that is tightly wound onto a metal core and is mounted to turn around inside an exhibit of large magnets. An electric conductor moves through a magnetic field, the magnetism will interface with the electrons in the conductor to induce a flow of electrical current inside it.

Electric Generator
Electric Generator

The conductor coil and its core are called the armature, connecting the armature to the shaft of a mechanical power source, for example, a motor, the copper conductor can turn at exceptionally increased speed over the magnetic field.

The point when the generator armature first starts to turn, then there is a weak magnetic field in the iron pole shoes. As the armature turns, it starts to raise the voltage. Some of this voltage is making on the field windings through the generator regulator. This impressive voltage builds up a stronger winding current, raises the strength of the magnetic field.

The expanded field produces more voltage in the armature. This, in turn, makes more current in the field windings, with a resultant higher armature voltage. At this time the signs of the shoes depended on the direction of flow of current in the field winding. The opposite signs will give the current to flow in the wrong direction.

How Does Electrical Generator Creates Electricity?

Actually, electrical generators don’t create electricity; instead of creating they change the energy from mechanical to electrical or chemical to electrical. This energy conversion can be done by capturing the motion power & converting it into electrical form through pushing electrons from the exterior source using an electrical circuit. An electric generator is basically working in reverse to the motor.

Some generators which are used at Hoover Dam will provide a vast amount of energy through transmitting the power which is created by turbines. The generators which are used in commercial, as well as residential, are very small in size but they depend on different fuel sources such as gas, diesel as well as propane to generate mechanical power.

This power can be used in a circuit to induce a current.
Once this current has been created then it is directed by using copper wires to power exterior devices, machines otherwise whole electrical systems.

Present generators use the principle of Michael Faraday’s electromagnetic induction because he discovered that once a conductor rotates within a magnetic field, then electrical charges could be formed to create a current flow. An electric generator is related to how a water pump forces water using a pipe.

Types of Electric Generators

The generators are classified into types.

  • AC generators
  • DC generators

AC Generators

These are also called alternators. It is the most important means of producing electrical power in many of the places since nowadays all the consumers are using AC. It works based on the principle of electromagnetic induction. These are of two types one is an induction generator and another one is a synchronous generator.

The induction generator requires no separate DC excitation, regulator controls, frequency control, or governor. This concept takes place when conductor coils turn in a magnetic field actuating a current and a voltage. The generators should run at a consistent speed to convey a stable AC voltage, even no-load is accessible.

AC Generator
AC Generator

Synchronous generators are large size generators mainly used in power plants. These may be rotating field type or rotating armature type. In the rotating armature type, the armature is at the rotor and the field is at the stator. Rotor armature current is taken through slip rings and brushes. These are limited due to high wind losses. These are used for low power output applications. Rotating field type of alternator is widely used because of its high power generation capability and the absence of slip rings and brushes.

It can be either 3 phase or two-phase generators. A two-phase alternator produces two completely separate voltages. Each voltage may be considered as a single-phase voltage. Each is generated voltage completely independent of the other. The three-phase alternator has three single-phase windings spaced such that the voltage induced in any one phase is displaced by 120º from the other two.

These can be connected either delta or wye connections. In Delta Connection each coil end is connected together to form a closed loop. A Delta Connection appears like the Greek Letter Delta (Δ). In Wye Connection one end of each coil connected together and the other end of each coil left open for external connections. A Wye Connection appears as the letter Y.

These generators are packaged with an engine or turbine to be used as a motor-generator set and used in applications like naval, oil and gas extraction, mining machinery, wind power plants, etc

Advantages

The advantages of AC generators include the following.

  • These Generators are generally maintenance-free, because of the absence of brushes.
  • Easily step up and step down through transformers.
  • Transmission link size might be thinner because of the step-up feature
  • Size of the generator relatively smaller than the DC machine
  • Losses are relatively less than DC machine
  • These Generator breakers are relatively smaller than DC breakers

DC Generators

DC generator is typically found in off-grid applications. These generators give a seamless power supply directly into electric storage devices and DC power grids without novel equipment. The stored power is carried to loads through dc-ac converters. The DC generators could be controlled back to an unmoving speed as batteries tend to be stimulating to recover considerably more fuel.

DC Generator
DC Generator

Classification of DC Generators

D.C Generators are classified according to the way their magnetic field is developed in the stator of the machine.

  • permanent-magnet DC generators
  • Separately-excite DC generators and
  • Self-excited DC generators.

Permanent magnet DC generators do not require external field excitation because it has permanent magnets to produce the flux. These are used for low power applications like dynamos. Separately-excite DC generators require external field excitation to produce the magnetic flux. We can also vary the excitation to get variable output power.

These are used in electroplating and electrorefining applications. Due to residual magnetism present in the poles of the stator, self-excited DC generators can able to produce their own magnetic field once it is started. These are simple in design and no need to have the external circuit to vary the field excitation. Again these self-excited DC generators are classified into shunt, series, and compound generators.

These are used in applications like battery charging, welding, ordinary lighting applications, etc.

Advantages

The advantages of a dc generator include the following.

  • Mainly DC machines have a wide variety of operating characteristics which can be obtained by selection of the method of excitation of the field windings.
  • The output voltage can be smoothed by regularly arranging the coils around the armature. This leads to fewer fluctuations which are desirable for some steady state applications.
  • No shielding need for radiation so cable cost will be less as compared to AC.

Other Types of Electric Generators

Generators are classified into different types like portable, standby, and inverter.

Portable Generator

These are extremely used in different applications and these are available in different configurations by changing power. These are helpful in normal disasters once grid power damages. They are used in residential, slighter commercial establishments like shops, retail outlets, at construction field to provide power to smaller tools, outdoor weddings, camping, outdoor events & to provide supply to agricultural devices like bore wells otherwise drip irrigation systems.

This kind of generator is powered through diesel fuel otherwise gas to provide short-term electrical power. The main characteristics of the portable generator are

  • It conducts electricity by using a combustion engine.
  • This can plug into different tools otherwise appliances through its sockets.
  • It can be connected into subpanels.
  • It is utilized in remote areas.
  • It uses less power to operate the freezer, Tv, and refrigerator.
  • The speed of the engine should be at 3600 rpm to make the typical current with a frequency of 60hz of current.
  • The engine speed can be controlled through the operator
  • It provides power to lights as well as tools

Inverter Generator

This type of generator uses an engine by connecting it into an alternator for generating AC power, and also uses a rectifier to change the AC to DC power. These are used in refrigerators, air-conditioners, boat automobiles which require the values of specific frequency as well as voltage. These are available in less weighty & solid. The characteristics of this generator mainly include the following.

  • It depends on modern magnets.
  • It uses higher electronic circuits.
  • It uses 3-phases for generating electricity.
  • It maintains a stable current supply to a device.
  • It is energy efficient because the speed of an engine will adjust itself based on the required power.
  • When it is used with the proper device then its alternating current can be fixed to any voltage as well as frequency.
  • These are lightweight and used in a car, boat, etc.

Standby Generator

This is one kind of an electrical system, used to operate through an automatic transfer switch that gives a signal to power up a device in power loss. The best characteristics of a standby generator include the following.

  • The operation of this can be done automatically
  • It is used in safety systems for standby lighting, elevators, life support equipment, medical & fire protection systems.
  • It provides stable power protection
  • It monitors utility power constantly
  • It executes self-tests automatically every week to check that it is responding properly or not to loss of power.
  • It includes two components like an automatic transfer switch & a standby generator
  • It detects the loss of power in seconds & enhances electricity
  • It operates by using natural gas otherwise liquid propane.
  • It uses a combustion engine internally.

Industrial Generators

Industrial generators are something different as compared with commercial otherwise residential applications. These are robust & rugged that perform under harsh conditions. The power supply characteristics provide will range from 20 kW-2500 kW, 120-48 volt & 1- phase to 3-phase supply.

Usually, these are more customized as compared with other types. The classification of these generators can be done based on the fuel used to make the engine run so that electric power can be generated. The fuels are natural gas, diesel, gasoline, propane, and kerosene,

Induction Generators

These generators are two types like self-excited and externally excited. Self-excited are used in windmills where the wind is used like a nontraditional energy source that converts to electrical energy. Externally excited are used in the applications of regenerative braking applications like cranes, hoists, electrical locomotives, and elevators.

Maintenance of Electric Generator

Electric generator maintenance is fairly similar to all types of engines. For every manufactures, it is very important to know its maintenance for all the generators. Normal maintenance is general inspection like leakage checking, coolant levels, glancing at the hoses & belts, cables & battery terminals checking. It is significant to examine the oil to change it frequently. The frequency of oil change mainly depends on the maker, how frequently it is used. If the generator uses diesel then it is necessary to change the oil for 100 hours of activity.

Once a year, filtering and fuel cleaning will degrade the diesel fuel very quickly. After some days of operation, this fuel can degrade through water pollution & microbes which results in blocked fuel lines as well as filters. Fuel cleaning uses biocides per annum within all types of generators apart from the standby generator, where it will attract dampness.

The cooling system should be maintained because it needs checking the level of coolant at accessible intervals during the shutdown time.

Battery power needs to check because issues within a battery can cause failures. Regular testing is required to notify the current status of the battery. It involves verifying the electrolyte levels as well as the exact gravity of the electric batteries.

It is also very significant to eliminate the generator for 30 minutes on a weekly basis under load. Remove surplus moisture, grease the engine & filter the fuel as well as foil. Once any movable pieces found anyplace on the generator must be located steadily in.

For further inspection, one should maintain its records to know the status of your generator.

Applications

The applications of electric generators include the following.

  • Across different cities, generators provide the supply to most of the power networks
  • These are utilized in transportation
  • Small scale generators give an excellent backup for household power requirements otherwise small businesses
  • These are used to drive electric motors
  • These are used before the power is set up at construction fields.
  • These are used in laboratories to give the range of voltage
  • Energy-efficient like fuel utilization can be reduced significantly

Disadvantages

The main drawback is they cannot stop major voltage fluctuations, due to this reason, conventional-type generators are not appropriate to operate voltage-sensitive consumers like PCs. laptops, TV sets otherwise music systems because they can damage them in the bad case.

Thus, this is all about an overview of an electric generator. An electric generator works on the electromagnetic induction principle. This principle was discovered through Michael Faraday. Basically, generators are electric conductor coils or generally a copper wire. This wire is tightly wound over a metal core & is placed to rotate approximately in an exhibit of big magnets.

An electric conductor rotates in a magnetic field and the magnetism will connect through the electrons within the conductor to provoke a current flow in it. Here, the conductor coil as well as its core is named as the armature. This is connected to the shaft of a power source. Now you have clearly understood the working and types of generators. Furthermore, any further more queries on this topic or on the electrical and electronic projects leave the comments below.

Electric Generator Image Source: topalternative

15 Comments

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  3. pravin Khanderao says:

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  5. Vidya singh says:

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