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Diesel generator and its major components

Learn about the major components of a diesel generator, working principle, types and lots more in this detailed guide by BISON. Let’s get started.

Table of Contents

All diesel generator components are combined in a motor to convert energy from one source to another form of energy. Therefore, generators operate by converting mechanical energy into electrical energy.

In a nutshell, a diesel generator fuels an alternator with mechanical energy, which, in the presence of a magnetic field and electromagnetic induction, is transformed into electrical current. To make the most of this product, it is crucial to comprehend the components of diesel generators.

Michael Faraday’s electromagnetic induction theory serves as the foundation for the operation of either a single or a number of synchronous generators. When discussing the various components of diesel generators, we shall explain this.

A generator is a machine used to generate electricity in many applications, from minor electrical equipment to large industrial machines. A popular option is to use grid electricity generated by fossil fuels or wind turbines and steam turbines in power plants.

There are many types of generators, including gasoline generator, portable, inverter, home generators that can run on natural gas, backup generators to keep the power on during a power outage, and substantial industrial generators. This article will focus on the diesel generator, how it works, and its essential components.

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Diesel generators

Diesel generators provide continuous or backup power to users such as homes, schools, hospitals, and industrial centers. They can be portable or large enough to fit around the house. However, there is a suitable unit for every user. Diesel generators convert fuel energy into electricity to power loads.

Diesel generator’s major components

Each diesel generator consists of at least nineteen components. Here’s each component with a brief description.

1) Diesel engine

Mechanical energy is produced by a diesel engine. Because the size of the engine directly correlates to the amount of electrical power generated, engine size is significant. This means that the engine size will be more significant if the required output is higher. Diesel engine types are also commonly used in cars, trucks, or larger vehicles.

2) Alternator

The alternator is the component responsible for generating the power output. Here, electromagnetic induction comes into play, as described below.

An alternator contains many complex parts, but the rotor is one of the most critical parts. It consists of a shaft rotated by mechanical energy provided by a motor and several permanent magnets mounted around it to generate a magnetic field.

This magnetic field continuously rotates around another critical part of the alternator, the stator. This set of different electrical conductors wound tightly around an iron core. Electromagnetic induction means that if an electrical conductor is held stationary and a magnetic field surrounds it, a current is induced.

To sum up, the alternator uses the mechanical energy which is generated by the diesel engine to drive the rotor, which produces a magnetic field that moves around the stator, thereby generating alternating current.

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3) Fuel system

The fuel system usually consists of a fuel tank and a pipe connecting it to the engine. From here, diesel can be supplied directly to the engine to start the process. The size of the fuel tank ultimately determines how long the generator can run.

A fuel tank on the base of the generator is usually supplied as standard with various silent canopy generators. If a large capacity of fuel is required; we can design and produce a custom extended base fuel system or add to an additional freestanding bulk fuel tank. Silent diesel generators have steel or plastic surrounds to reduce noise.

For more extensive generator plans that require the generator set to be placed in a soundproof room, the separate fuel system is usually located inside or below the room, or sometimes both.

Come to BISON and find out what you need to know about reducing fuel consumption of diesel generators.

4) Stabilizer

The voltage regulator is the most complex part of the generator. This part has an explanatory purpose: to regulate the voltage output. The things inside the voltage regulator are very detailed, so that we won’t go into details in this article.

It makes sure that the generator generates electricity at an adequately regulated voltage. Without a voltage regulator, there would be extreme fluctuations based on engine speed. All the electronic devices we use cannot control this erratic power supply. The goal of this part is to keep everything smooth and consistent.

5) Cooling system and exhaust system

Both parts have essential functions. The cooling system must prevent the generator from overheating. Coolant is released in the alternator, offsetting all the extra heat from the engine and alternator. The coolant then goes through the heat exchanger to absorb all this heat and expel it from the generator.

The exhaust system works similarly to the exhaust system of a car. It captures any gasses the diesel engine produces, enters them through the ductwork, and removes them from the generator set.

6) Lubrication system

The lubrication system is the part connected to the engine, and oil is pumped into it to ensure that each part works smoothly and does not rub against other parts. With a proper lubrication system, the diesel generator is likely to succeed.

How To Choose The Right Lubricant?

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7) Battery charger

A diesel engine needs a tiny electric motor to help it run. The small motor works with the battery and needs to be charged.

Come to BISON, check Maintain The Battery Of The Diesel Generator.


8) Control panel

This part is only in the case of controlling and operating the generator. This has every control object, including the start button, engine fuel indicator, frequency switch, coolant temperature indicator, etc., enabling the user to perform different jobs or check certain things.

The control panel starts and stops the generator and monitors the engine and alternator for monitoring, maintenance, and control. The control panel makes sure everything is running correctly. It can also provide synchronization for parallel job activations.

9) Assembly frame

Every generator needs to be fixed somehow; this is the main frame of the assembly. It houses the entire generator; all the different diesel generator parts are manufactured here.

It holds everything together and may be an open design – or closed for extra security and sound attenuation. Outdoor generators are often installed in a weatherproof protective frame to prevent damage.

10) Diesel tank

As known by its name it is used to store diesel oil. They usually range from 500 to 1000 liters. Diesel tank capacity also depends on the length of time for backup.

11) Water separator

Most of the time, the diesel generator set is in the open air, and water may flow into its fuel tank during the rainy season. That’s why this oil water separator is used to separate water.

12) Actuator

With the help of actuators, we can get information on how much diesel to load wisely. This saves on extra diesel costs. In many ways, it saves both fuel and money.

13) Radiator and fan

If the generator runs for a longer time, the distilled water will also get hot and must be cooled. For this, radiators and fans are necessary.

14) Turbocharger

It injects filtered air into the engine and expels the carbon dioxide produced.

15) Silencer

There is a lot of noise only when the DG unit is on. Silencer has been used to block out this noise.

16) Coupling

It is used to connect the alternator and engine. As the engine spins, it also spins as the alternator is connected with the help of a coupling.

17) Exciter

The voltage is set according to the commands received from the AVR.

18) Flywheel

The flywheel prevents sudden changes when the engine rotor spins at 1500 RPM.

19) Circuit breaker

Even if the DG unit accidentally suffers a short circuit or any electrical fault, this will prevent a lot of damage inside the machine by tripping it.

Types of diesel generators

Here are the types of diesel generators:

1)  Portable generator

Portable generator is used to run small devices. Therefore, gas or diesel is used as combustion fuel. This is an affordable and good tool for temporary supplies.

2) Inverter generator

This type of machine uses an alternator to generate electricity. It is connected to the diesel engine. In this way, power is obtained in 3 stages.

It is supplied with alternating current, which is changed into direct current. Utilized in the previous phase and once more using AC power obtained from the DC power source.

3) Standby generator

Everyone around us must have seen this diesel generator. It is more prominent in size and more common in standby mode. This generator is only run in emergencies. Due to the high rating, KVA is available in the market.


You are familiar with the working principle of diesel generators and all components. In a nutshell, a diesel engine provides mechanical energy to an alternator, which is then converted into electrical current by the action of a magnetic field and electromagnetic induction.

Find the right generator from BISON

At china BISON generator, we pride ourselves on being able to provide our customers with quality and affordable generators of different types. We only supply inspected and verified equipment, ensuring you can rely on our products. We’re the wholesale suppliers of generators across the world.

We have knowledgeable industry experts who will help you find the generator and products that best meet your needs and budget. Our dedication to providing reliable, cost-effective, and high-quality machinery helps us meet the power generation needs of companies worldwide.

B Checks are performed weekly or after (300-350) hours of operation. The following parameters should be checked during this inspection:


  • Change the engine oil.
  • Change oil, fuel, and bypass filters.
  • Replace the air filter.
  • Replace the water separator if necessary.

The output produced by the alternator in a diesel generator is an alternating current, which is converted to direct current with the help of a rectifier.

KVA is 1,000 Volt Amperes. Volts are electrical voltages. Amperes are electric currents. The apparent power is equal to the product of volts and amperes. Watt (W) is a measure of absolute power.

The most common diesel and gasoline engines spin at 1500 rpm or 3000 rpm, or revolutions per minute. (Engine RPM can also be lower than 1500).

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what is generator THD?

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