What is the main purpose of a generator?

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.

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.

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.

Britannica Quiz

Energy & Fossil Fuels

Rotor

elementary synchronous generator

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. 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 in Figure 2 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.

Are you a student? Get Britannica Premium for only $24.95 - a 67% discount!

Subscribe Now

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 in Figure 2 and will be maximum in the opposite direction 180° later. The waveform of the voltage will be approximately of the sine form shown in Figure 1.

Further reading:
Energy

Energy Choice: How to Switch Your Electric Company
The 3 Different Types of Solar Power Systems Explained
How Much Do Solar Batteries Cost? (2024 Guide)
How do you know if diesel is getting into oil?

Frequency

The rotor structure of the generator in Figure 2 has two poles, one for magnetic flux directed outward and a corresponding one for flux directed inward. One complete sine wave is induced in the stator coil for each revolution of the rotor. The frequency of the electrical output, measured in hertz (cycles per second) is therefore equal to the rotor speed in revolutions per second. To provide a supply of electricity at 60 hertz, for example, the prime mover and rotor speed must be 60 revolutions per second, or 3,600 revolutions per minute. This is a convenient speed for many steam and gas turbines. For very large turbines, such a speed may be excessive for reasons of mechanical stress. In this case, the generator rotor is designed with four poles spaced at intervals of 90°. The voltage induced in a stator coil, which spans a similar angle of 90°, will consist of two complete sine waves per revolution. The required rotor speed for a frequency of 60 hertz is then 1,800 revolutions per minute. For lower speeds, such as are employed by most water turbines, a larger number of pole pairs can be used. The possible values of rotor speed, in revolutions per minute, are equal to 120 f/p, where f is the frequency and p the number of poles.

All About Functions of Generator

What is the function of every generator? Generators play a vital role to meet the demands of power for residential or industrial premises during a power outage. Different brands of new or used diesel generators for sale at CSDG work best to keep your lighting and appliances running. One of the crucial sources of backup power, generators, help you to meet electricity needs in an emergency.

Generators create electrical energy to power appliances running on electricity by burning the fuel it uses for producing electricity. The generator includes different elements like a fuel system, engine, voltage regulator, alternator, a control panel, lubrication system, cooling, and exhaust system.

How Do Generators Function?

Let’s check out some essential components used in the functioning of the generator:

#1 Alternator of the generator:

An alternator is the component of the generator that creates electrical output for producing the electricity. The stator and rotor of alternators surround the latter through a housing unit that includes the significant functions of the generator. Though housing is of plastic or metal, metal is highly favorable as it is less receptive to the destruction that can uncover the moving parts. The primary constituents of alternators are needle bearings or ball bearings. From the two fundamental elements, ball bearings have a higher lifespan as compared to needle bearings.

#2 Fuel system of the generator:

The fuel system of a generator has major components such as the connection of the pipe from the fuel tank to the engine, a ventilation pipe, and the overflow connection from a tank of fuel to the drainage pipe, a fuel filter, a fuel pump, and a fuel injector. An external fuel tank is for large commercial generators. Small generators include fuel tanks either at the top or located at the base. At CSDG, we have top brands of generators like caterpillar c27, Kohler, blue star, etc.

#3 Control panel of the generator:

Full functioning is at the control panel of the generator and is also the part where the generator is switched on. Significant components of the control panel are an electric start and the shut-down. While automatic functioning is provided by some of the generator sets when there is no power supply. Engine gauges along with a voltage regulator are also present in the control panel. It helps to keep a check on the temperature of the coolant, the pressure of the oil, and the battery voltage.

#4 Engine of the generator:

One of the significant parts of the generator that produces mechanical energy is the engine. Generators are available in engines of a wide range. Engines regulate entirely electricity created by the generator in the generator. Different fuels on which generator engines function are natural gas, diesel, gasoline, and liquid propane.

Types of generators:

Different variety of generators are industrial generators, residential standby generators, commercial standby generators, portable diesel generators, to name a few. However, different operating applications are in association with varying types of generators. Portable generators use the extension to power small electrical appliances. In the case of other generators, the transfer switch is connected to the main electrical panel to transport electricity directly without the involvement of cords.

Summing Up:

So, the aforementioned are the essential parts of the generators used in terms of function. The usage of the generator ultimately depends on the application for which it applies, commercial use or residential use. Therefore, you must consider a purchase of one of the top-rated brands of generators such as the blue star, Cummins c15 generator, Caterpillar, Kohler diesel generator, etc. At CSDG, we have different types of diesel generators that you can choose as per your budget and preference. To buy diesel generators, you can contact us, and we will assist you to select the right choice as per your requirement.

CONTACT US FOR ANY ASSISTANCE

Read more articles about Kohler diesel generators

Frequently asked questions

What is the function of a generator?

Generators create electrical energy that is used to power important appliances. The energy is created by burning fuel and turning this energy into electricity. Generators are often used in large facilities, such as hospitals and building sites, to provide backup power for vital machinery.

What is a voltage regulator?

A voltage regulator is a system that is designed to automatically maintain a constant voltage. Most voltage generators use a feed-forward design and some include negative feedback. Voltage regulators ensure that generators are working efficiently.

Do diesel generators require a fuel tank?

Yes. Diesel generators require a fuel tank to supply the generator with burning material. Fuel tanks must supply the generator with a continuous flow of fuel. This is transferred via an electric motor through a pump to a smaller tank and then flows through to the main engine. The engine fuel indicator helps the operator know the existing level of fuel in the tank.

How does a generator use mechanical energy?

Diesel generators use mechanical energy to create electricity. Diesel fuel provides the generator with chemical energy that is then converted into mechanical energy through combustion. This mechanical energy is used to propel the generator to create energy that can be used to power appliances.

How does a generator work?

Generators convert energy, produced by fuel or rotation, into electrical power that can power appliances. All generators rely on combustion to create the energy that is needed and the elements of the process will differ depending on the generator fuel type. Diesel generators use an exhaust system to diffuse any unwanted chemicals. In an electric generator, a conductor coil is used to create energy.