Generator

Jai Ganesh · Yesterday 18:17:42

Generator

Gist

Electric generator is any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. Generators also produce the electrical power required for automobiles, aircraft, ships, and trains.

A generator is a device that converts mechanical energy (like rotation from an engine or turbine) into electrical energy, working on the principle of electromagnetic induction (Faraday's Law) where a conductor moving through a magnetic field creates an electric current. These machines power electrical grids, provide backup power, and are essential for converting various power sources (steam, wind, gas, water) into usable electricity, producing either Alternating Current (AC) or Direct Current (DC).

Summary

In electricity generation, a generator, also called an electric generator, electrical generator, and electromagnetic generator is an electromechanical device that converts mechanical energy to electrical energy for use in an external circuit. In most generators which are rotating machines, a source of kinetic power rotates the generator's shaft, and the generator produces an electric current at its output terminals which flows through an external circuit, powering electrical loads. Sources of mechanical energy used to drive generators include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. Generators produce nearly all of the electric power for worldwide electric power grids. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday.

The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators are very similar. Some motors can be used in a "backward" sense as generators, if their shaft is rotated they will generate electric power.

In addition to its most common usage for electromechanical generators described above, the term generator is also used for photovoltaic, fuel cell, and magnetohydrodynamic powered devices that use solar power and chemical fuels, respectively, to generate electrical power.

Details

A generator refers to an electrical device that converts a form of energy into electricity.

The input energy can be in the form of fuel like petrol, diesel, or natural gas. It could also be from water (hydroelectric), wind, or solar power.

How Do Generators Work?

Generators work by using a fuel source to create mechanical energy.

It is essential to note that a generator does not actually 'create' electrical energy.

Instead, it utilizes the mechanical energy supplied to it to force the movement of electric charges available in the wire of its windings through an external electric circuit.

This flow of electric charges forms the output electric current supplied by the generator.

Michael Faraday discovered the modern-day generator, which works on the principle of electromagnetic induction. This is where a magnetic field is used to create voltage and an electric current in a nearby conductor.

Types of Generator

There are two types of generators:

1) Dynamos

A dynamo uses mechanical energy to create direct current (DC) electricity.

It is considered the first electrical generator used to transfer power for industry and the basis of many other later electric-power conversion devices such as the electric motor, rotary converter, and alternating-current alternator.

2) Alternators

The second type of generator is the alternator, also known as a synchronous generator, which uses mechanical energy to create alternating current (AC) electricity.

Alternators are used to produce the power for the electrical systems of modern vehicles. Another usage is in the diesel-electric locomotives.

Functions of Generators

Generators have many functions. Some of these include:

1) Back-up Power During Power Outages

When there are power outages, most especially for non-emergency reasons, one of the functions of generators is to provide backup power.

Generators are beneficial for homes and businesses that rely on electricity to function.

2) Standby Power for Businesses

Another common usage for generators is standby power for businesses. This is where a generator is used as a backup in case the main power supply is lost. This ensures that the business can continue its operation as usual without interruption.

Temporary Power Supply

A generator can also be used as a temporary power supply for events or construction sites. This is where a generator is used to provide power for a limited period of time.

Permanent Power

In some cases, generators are used as a permanent power source. This is where the generator is used to provide power for an extended period of time.

Supporting the Main Power Supply

Generators are sometimes used to support the main power supply. This is where the generator is used to supplement the power supply during times of high demand.

Generator Safety Tips

Here are ten useful safety tips to follow when using a generator:

1. Do not set a generator indoors or in an enclosed space. The generator must be placed at least 20 feet from the house, and the engine when exhaust must be directed away from windows or doors.

2. When buying a generator, it must have a built-in carbon monoxide (CO) safety technology. There are new generators that have a device that detects dangerous levels of carbon monoxide and turns off the machine when levels rise too high.

3. Avoid electrical hazards. The outlets on the generator can be used if you do not have a transfer switch yet. Just make sure you follow certain precautions. Thus, it is advisable to plug in devices directly to the generator.4.

4. Do not attempt to backfeed your house. Backfeeding refers to the attempt to power the wiring on your home by plugging the generator into a wall outlet.

This reckless and dangerous act could present an electrocution risk to utility workers and neighbors with the same utility transformers. Thus, this could also be a cause of an electrical fire.

5. Install a transfer switch prior to the next storm. The purpose of a transfer switch is to connect the generator to your circuit panel and allows you to power hardwired appliances while averting the safety risk of using extension cords.

6. Never set a portable generator in the rain. Keep your generator shielded from the rain. Never operate a generator inside a wet or damp area to avoid electrocution.

7. Disable a gas-powered generator and let it cool before refueling. Letting the engine cool lowers the risk of burns while refueling.

8. Keep extra gasoline and store it properly. When you store extra gasoline, be sure to store it in a container approved by the American National Standards Institute (ANSI) and position it in a cool and well-ventilated area.

9. Only use generators that are rated for the voltage and amperage required by your equipment. Using a generator that is not properly rated could cause damage to your equipment.

10. Make sure the generator is properly grounded. Your generator must properly be grounded to avoid electrocution.

Key Takeaways

A generator is a machine that changes mechanical energy into electrical energy.

Generators can be utilized for various purposes, such as backup power during power outages, standby power for businesses, temporary power supply, permanent power, and supporting the main power supply.

There are different types of generators, such as dynamos and alternators.

Generators must be used safely to avoid risks, such as electrocution and fires.

Some safety tips include never running a generator in an enclosed space or indoors, placing the generator at least 20 feet from the house and engine, and using a generator with built-in carbon monoxide (CO) safety technology.

Installing a transfer switch is also recommended to avoid using extension cords. If you must use extension cords, make sure they are heavy-duty.

Extra gasoline should be stored in a container approved by the ANSI in a cool and well-ventilated area.

When using a generator, make sure that it is properly rated for the voltage and amperage required by your equipment and properly grounded.

By observing these safety tips, you can use a generator safely and effectively.

FAQs

1. What is a generator?

A generator converts mechanical energy into electrical energy. It is usually powered by an internal combustion engine, such as a diesel or gasoline engine.

2. How do generators work?

Generators work by using a fuel source to create mechanical energy. It utilizes the mechanical energy supplied to it to force the movement of electric charges available in the wire of its windings through an external electric circuit. This flow of electric charges forms the output electric current supplied by the generator.

3. What are the different types of generators?

The two main types of generators are dynamos and alternators. A dynamo uses mechanical energy to create direct current (DC) electricity. An alternator uses mechanical energy to create alternating current (AC) electricity.

4. What are the functions of generators?

Generators can be utilized for various purposes, such as backup power during power outages, standby power for businesses, temporary power supply, permanent power, and supporting the main power supply.

5. What are some generator safety tips?

Some safety tips for using generators include never running a generator in an enclosed space or indoors, placing the generator at least 20 feet from the house and engine, and using a generator with built-in carbon monoxide (CO) safety technology. Installing a transfer switch is also recommended in order to avoid using extension cords. If you must use extension cords, make sure that they are heavy-duty. Extra gasoline should be stored in a container that is approved by the ANSI in a cool and well-ventilated area. When using a generator, make sure that it is properly rated for the voltage and amperage required by your equipment and properly grounded.

Additional Generator

electric generator, any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. Generators also produce the electrical power required for automobiles, aircraft, ships, and trains.

The mechanical power for an electric generator is usually obtained from a rotating shaft and is equal to the shaft torque multiplied by the rotational, or angular, velocity. The mechanical power may come from a number of sources: hydraulic turbines at dams or waterfalls; wind turbines; steam turbines using steam produced with heat from the combustion of fossil fuels or from nuclear fission; gas turbines burning gas directly in the turbine; or gasoline and diesel engines. The construction and the speed of the generator may vary considerably depending on the characteristics of the mechanical prime mover.

Alternating-current generators

Nearly all generators used to supply electric power networks generate alternating current, which reverses polarity at a fixed frequency (usually 50 or 60 cycles, or double reversals, per second). Since a number of generators are connected into a power network, they must operate at the same frequency for simultaneous generation. They are therefore known as synchronous generators or, in some contexts, alternators.

Synchronous generators

A major reason for selecting alternating current for power networks is that its continual variation with time allows the use of transformers. These devices convert electrical power at whatever voltage and current it is generated to high voltage and low current for long-distance transmission and then transform it down to a low voltage suitable for each individual consumer (typically 120 or 240 volts for domestic service). The particular form of alternating current used is a sine wave, which has the shape shown in Figure 1. This has been chosen because it is the only repetitive shape for which two waves displaced from each other in time can be added or subtracted and have the same shape occur as the result. The ideal is then to have all voltages and currents of sine shape. The synchronous generator is designed to produce this shape as accurately as is practical. This will become apparent as the major components and characteristics of such a generator are described below.

Rotor

An elementary synchronous generator is shown in cross section in Figure 2. The central shaft of the rotor is coupled to the mechanical prime mover. The magnetic field is produced by conductors, or coils, wound into slots cut in the surface of the cylindrical iron rotor. Because of Faraday’s law of induction, the rotating magnetic field produces a changing magnetic flux that induces a voltage in the stator. This set of coils, connected in series, is thus known as the field winding. The position of the field coils is such that the outwardly directed or radial component of the magnetic field produced in the air gap to the stator is approximately sinusoidally distributed around the periphery of the rotor. In Figure 2, the field density in the air gap is maximum outward at the top, maximum inward at the bottom, and zero at the two sides, approximating a sinusoidal distribution.

Stator

The stator of the elementary generator consists of a cylindrical ring made of iron to provide an easy path for the magnetic flux. In this case, the stator contains only one coil, the two sides being accommodated in slots in the iron and the ends being connected together by curved conductors around the stator periphery. The coil normally consists of a number of turns.

When the rotor is rotated, a voltage is induced in the stator coil. At any instant, the magnitude of the voltage is proportional to the rate at which the magnetic field encircled by the coil is changing with time—i.e.,the rate at which the magnetic field is passing the two sides of the coil. The voltage will therefore be maximum in one direction when the rotor has turned 90° from the position shown and will be maximum in the opposite direction 180° later.

Waterwheel generators

Hydraulic turbines are of various types, the choice depending largely on the height of water fall and on the power rating. The range of speed for which hydraulic turbines give acceptable efficiency is much lower than for steam turbines. The rotational speed is generally in the range of 60 to 720 revolutions per minute. The construction of low-speed synchronous generators is substantially different from that of high-speed units. To produce power at 60 hertz, the number of rotor poles is in the range of 10 to 120 for the above speed range. For these machines the rotor poles are of the projecting, or salient, type. Each pole, made of laminated magnetic steel, is encircled by a field coil. The pole is shaped so as to make the air-gap magnetic field distribution approximately sinusoidal.

Large hydraulic generators may have individual ratings in excess of 200 megavolt-amperes. They are mounted with a vertical shaft directly coupled to the turbine. The combination is usually supported on a single bearing, either above or below. The diameter is made relatively large to obtain a high peripheral velocity at low rotational speeds. The axial length of the generator is relatively short. The windings are frequently water-cooled. The rotor has to be designed to withstand a considerable overspeed condition that may arise if the generator loses its electrical load and there is a significant time delay in cutting off the water flow to the turbine.

Generators for motor vehicles

Vehicles such as automobiles, buses, and trucks require a direct-voltage supply for ignition, lights, fans, and so forth. In modern vehicles the electric power is generated by an alternator mechanically coupled to the engine. The alternator normally has a rotor field coil supplied with current through slip rings. The stator is fitted with a three-phase winding. A rectifier is used to convert the power from alternating to direct form. A regulator is used to control the field current so that the output voltage of the alternator-rectifier is properly matched to the battery voltage as the speed of the engine varies.

Permanent-magnet generators

For some applications, the magnetic field of the generator may be provided by permanent magnets. The rotor structure can consist of a ring of magnetic iron with magnets mounted on its surface. A magnet material such as neodymium-boron-iron or samarium-cobalt can provide a magnetic flux density in the air gap comparable to that produced with field windings, using a radial depth of magnet of less than 10 millimetres. Other magnet materials such as ferrite can be used, but with a considerable reduction in air-gap flux density and a corresponding increase in generator dimensions.

Permanent-magnet generators are simple in that they require no system for the provision of field current. They are highly reliable. They do not, however, contain any means for controlling the output voltage. A typical example of use is with a wind turbine where the generator output of variable voltage and frequency is supplied to a power system through an electronic frequency converter.

Math Is Fun Forum

#1 Yesterday 18:17:42

Generator

Board footer