9 Electric Generator Parts and their Functions Explained

Electric generator parts include engine; fuel system, engine, alternator, control panel, voltage regulator, lubrication system, cooling system, main frame, and battery charger.

Each of these parts is briefly discussed as follows;






1). Engine as one of the Electric Generator Parts

The engine is one of the most important parts of an electric generator.

A generator engine is the unit in which most of the energy conversions occur. Chemical-to-heat energy conversion occurs when the fuel undergoes combustion, as the fuel is supplied to the engine.

Heat-to-mechanical energy conversion occurs when the heat energy from combustion of the fuel, is transformed to mechanical energy in the engine, through fluid-heating and hydrodynamic processes [9].

Mechanical energy is subsequently converted to electricity in the engine, through electromagnetic processes.

Based on the foregoing assessment, it can be argued that the engine is responsible for a large portion of the role of electricity generation, compared to other parts of an electric generator.

The primary function of a generator engine is to generate usable energy and power from fuel. Engines may vary greatly in design, based on factors such as the type of fuel to be used and the amount of power supply that is required.

A wide variety of fuels can be used as energy source in a generator engine. These include propane, natural gas, diesel and gasoline, among others [7]. It is important to note that these fuels vary based on their energy density and combustion efficiency.

As an energy source, fuels also differ in terms of their effect on the environment. While some may have minimal environmental effect, others may contribute significantly to environmental degradation, climate change and global warming.

Like other parts of an electric generator the size of the engine may differ. This size determines the portability, capacity, and utilization conditions of the electric generator.

generator engine, parts of an electric generator

Parts of an Electric Generator : The Engine (Credit: Biswarup Ganguly 2014 .CC BY 3.0.)


2). Fuel System

The fuel system comprises of all parts of an electric generator which are involved in storage and dispensation of fuel.

This system works in conjunction with the engine to ensure that a primary source of energy is made available to the components that need them. It is as important as the engine, because it determines if and how the generator will work.

The length of operation of an electric generator in each recharge depends on the size and capacity of the fuel system. Also, a fuel system must be recharged with its specific type of fuel in order to ensure optimal operation of the generator.

Components of an electric generator fuel system include fuel tank, flow pipe, fuel pump, separator, vent hose, overflow hose and injector.

The fuel tank is the main reservoir which collects and holds the fuel that is used by the electric generator. Its capacity determines how much fuel can be stored by the generator at any given time, and hence, how long the generator can operate on a single recharge.

Fuel from the tank is supplied to the engine by the flow pipe of fuel pipe. In some electric generators, there is also a reverse-flow pipe, to return excess fuel from the engine to the tank.

Where this integrated reverse-flow pipe is not available, the overflow pipe is used to channel excess fuel to the drain system of the generator, thereby minimizing spillage.

The fuel tank is also often equipped with a ventilation pipe or vent hose, which controls fluid pressure in the tank to prevent hazards and malfunctions.

Where there are support systems to the main fuel system, a fuel pump is needed to channel fuel from the main tank to an auxiliary one.

Potentially harmful impurities are isolated from the fuel system by the filter. This component protects other parts of an electric generator from potential damage, by removing foreign materials from fuel as it is introduced into the system.

Fuel injector serves the purpose of supplying fuel to the combustion chamber, in an atomized form [8] that is compatible with the working-pace and mechanism of fuel combustion in the generator.


3). Alternator as one of the Electric Generator Parts

The alternator can be described as a subsystem which comprises of all parts of an electric generator involved in the electromagnetic conversion of mechanical energy to electricity.

It is a highly important subsystem and may be alternatively referred to as the generator head or “genhead“.

Subcomponents of the alternator include rotor, stator, and bearings. These work in synchrony to generate electricity through electromagnetic induction.

The stator is a stationary body in the electric generator [5], which may occur either as a homogenous, solid metal or as a coil of conductive wire around a solid metal core. It interacts with the rotor to generate electricity through electromagnetic induction.

The rotor is a moving component which may perform rotary or translational motion. As a result of this motion, a moving magnetic field is created, which interacts with the stator to generate electricity.

In an electric generator, the magnetic field is created by excitation (using electric current), induction (using a nearby magnetic body) or by a permanent magnet. The rotor is supported by bearings, which enable it to rotate with minimal friction or resistance. This ensures that energy losses are minimized.

alternator genhead generator head, parts of an electric generator
Parts of an Electric Generator : The Alternator (Credit: Dual Freq 2008 .CC BY-SA 3.0.)


4). Voltage Regulator

The voltage regulator controls the output voltage which is produced by the combined operation of all parts of an electric generator.

One of the main functions of the voltage regulator is conversion of a portion of the alternating current (AC) produced by the generator, to direct current (DC) which is used for excitation of the generator system, among other applications. A rectifier is part of the voltage regulator, and plays a key role in current conversion and modification.


5). Lubrication System

The lubrication system in an electric generator, minimizes friction between the moving parts of the system to ensure that there is no heating, and the system operates smoothly and efficiently.

Basically, the system comprises of a pumping mechanism that transmits a lubricant to the parts of an electric generator where lubrication is most needed. The engine is a good example of these parts, which require lubrication to operate.

Oil (lubricant) in the lubrication system should be either refilled or replaced at regular intervals of time, which depend on the characteristics and mode of usage of the generator.


6). Cooling System

The role of the cooling system in an electric generator is to regulate the temperature of the system and prevent overheating, which may cause loss of energy and low-efficiency.

Cooling systems protect other parts of an electric generator from the potentially harmful effects of excessively high temperature.

In order to achieve this, there are two key subcomponents which should be present and operational in a cooling system. These are the coolant-circulation unit, and the exhaust unit.

As the name implies, the coolant-circulation unit is responsible for circulating a coolant through the electric generator system. This coolant may be comprised of conductive and heat-absorbent fluid like hydrogen and water [6].

The need for a coolant system is most significant for large generators which have complex configurations, large size and capacity, and therefore, large heat-production potential.

Using the coolant circulation unit, excess heat from the engine can be removed through heat exchange between the engine components and the conductive fluid. This mechanism is very useful for industrial generators where the demand for output-efficiency and performance is high

In large generators, the coolant fluid can be checked regularly in order to ensure optimal performance of the unit.

The exhaust unit is typically part of the cooling system of an electric generator. It comprises of a vent mechanism to remove unwanted gaseous byproducts of fuel combustion like carbon monoxide. This is important since such effluents can cause environmental degradation, health problems and global warming.


7). Control Panel as one of the Electric Generator Parts

Control panel is the part of a generator which enables users to easily and effectively operate the system.

It can also be described as a user interface that is equipped with regulatory units that control all parts of an electric generator.

There are various functions that can be integrated into the control panel. One of these is monitoring of the generator’s performance while in operation [1]. Another is to regulate and adjust the functioning mode of different parts of the generator.

In order to achieve its purpose, control panels are equipped with switches and gauges. An example of a switch that is part of the control panel, is the power switch of the generator, which enables it to start.

Gauges are used to assess the conditions under which the electric generator is functioning, such as temperature, pressure, rotor speed, voltage, and recharge (fuel, lubricant). Information on these parameters help users to prevent potential problems that could arise due to poor working conditions.

control panel, parts of an electric generator
Parts of an Electric Generator : Control Panel (Credit: Secoy, A 2016 .CC BY-SA 4.0.)


8). Battery Charger as one of the Electric Generator Parts

In an electric generator, the battery charger supplies voltage to the battery, which is used to start the generator.

The key role of this component is to provide what is known as ‘float voltage’ to the battery [4]. This voltage is responsible for keeping the battery at a sufficiently-charged level to start the generator.

The battery charger in an electric generator is usually designed based on electric motor technology [3], so that it operates similar to an electric motor. Its operation is usually spontaneous, and occurs when the start process of the generator is initiated.

Based on the capacity of the generator and the float voltage needed to charge the battery, various designs of battery chargers can be used. The materials used to make these chargers may also vary based on the demand, scale and conditions of operation.


9). Frame as one of the Electric Generator Parts

Also known as the main assembly, skid, or main frame, this component is responsible for assembling, enclosing, and protecting all major parts of an electric generator.

Its functions are to provide structural support, rigidity and enclosure to the generator system [2], and to protect parts of the system from damage by mechanical and environmental factors.

Because of the frame, all parts of an electric generator can be moved from one place to another as a unit. This makes it easier, safer, and more efficient to use the generator.


Secondary Components: Accessories that can be found in an Electric Generator

Accessories or secondary components of an electric generator include radiator, transfer switch, trailer and load bank.

The radiator is an accessory of the coolant system. Its role is to remove absorbed heat from the coolant, to enable it continue functioning as heat absorber for the generator engine. As a result of the radiator’s operation, the generator and coolant system are able to operate under feasible temperature conditions.

The transfer switch helps to ensure that power supply from the system is safe, by preventing interference in the power supply process, from other parts of an electric generator.

It also simplifies the power supply process by ensuring that a single point serves as the power transfer unit of the generator.

In backup generators, the transfer switch can be designed and programmed to function automatically when there is failure of the primary power source.

Trailer in an electric generator, is an accessory whose purpose is to simplify the process of moving the generator. It may come in any of various designs, depending on the size and structural configuration of the generator.

The role of load banks in an electric generator, is to regulate the electricity supply process of the system. This is achieved by assessing the performance of the generator under various loading conditions.

Load banks enable the generator to work efficiently as a power supply system, by improving the power production and supply process at the levels of fuel combustion, electricity generation and electricity transfer.  



Electric generator parts include;

  1. Engine
  2. Fuel System
  3. Alternator
  4. Voltage Regulator
  5. Lubrication System
  6. Cooling System
  7. Control Panel
  8. Battery Charger
  9. Frame


Accessories, or secondary parts of an electric generator include;

  1. Radiator
  2. Transfer switch
  3. Trailer
  4. Load bank



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2). Atoo, A. E.; Adewumi. I. O. (2014). “FUELLESS GENERATING SET: DESIGN, CONSTRUCTION & PERFORMANCE EVALUATION.” Third International Conference on Engineering and Technology Research, OGBOMOSHO OYO STATE NIGERIA, Volume: 3. Available at: https://www.researchgate.net/publication/273946299_FUELLESS_GENERATING_SET_DESIGN_CONSTRUCTION_PERFORMANCE_EVALUATION. (Accessed 15 May 2022).

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6). Martynov, P. N.; Gulevich, A. V.; Orlov, Y. I.; Gulevsky, V. A. (2005). “Water and hydrogen in heavy liquid metal coolant technology.” Progress in Nuclear Energy 47(s 1–4):604–615. Available at: https://doi.org/10.1016/j.pnucene.2005.05.063. (Accessed 15 May 2022).

7). Nwaokocha, C.; Okezie, S. (2016). “A CONVERSION OF PETROL GENERATOR TO ENABLE THE USE OF LIQUIEFIED PETROLEUM GAS (PROPANE).” Available at: https://www.researchgate.net/publication/327802863_A_CONVERSION_OF_PETROL_GENERATOR_TO_ENABLE_THE_USE_OF_LIQUIEFIED_PETROLEUM_GAS_PROPANE. (Accessed 15 May 2022).

8). Shatrov, M. G.; Malchuk, V. I.; Dunin, R. Y. (2020). “A Laboratory Investigation into the Fuel Atomization Process in a Diesel Engine for Different Configurations of the Injector Nozzles and Flow Conditions.” Fluid Dynamics and Materials Processing 16(4):747-760. Available at: https://doi.org/10.32604/fdmp.2020.08991. (Accessed 15 May 2022)..

9). Venkatesh, B. K.; Vardhan, M. V. H.; Prashanth, K. P. (2016). “Conversion of Waste Heat Energy from Internal Combustion Engine using Thermo Electric Generator.” Available at: https://www.researchgate.net/publication/331989556_Conversion_of_Waste_Heat_Energy_from_Internal_Combustion_Engine_using_Thermo_Electric_Generator. (Accessed 15 May 2022).

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