Basic Structure And Application of Diesel Generator Set

A diesel generator set combines a diesel engine and an alternator to produce reliable electrical power for a wide range of applications. The diesel engine provides the mechanical power required to drive the generator, which then converts that energy into electricity. Due to their durability, efficiency, and dependable performance, diesel generators are widely used across industries including construction, mining, manufacturing, healthcare, transportation, telecommunications, and emergency backup power systems.

A typical diesel generator set consists of four main components: the diesel engine, the AC alternator, the control system, and the base frame. These integrated components work together to ensure stable power generation, efficient operation, and easy monitoring. The illustration below provides a clear overview of the main parts and structure of a diesel generator set.

Structure of Diesel Generator Set

Diesel Engine

Diesel Engine is a compression ignition engine with diesel fuel. It is widely used as the prime mover for electrical power generating unit in the range from 20 KW to 5000 KW.

Diesel engine is classified in different ways. It can be classified in accordance to its number of strokes, cooling way, air admission way, cylinder number, cylinder arrangement and rotation speed. The detailed information is as follows:

1. By Engine Cycle
Diesel engines are commonly available in two-stroke and four-stroke configurations. Among these, four-stroke diesel engines are the most widely used due to their superior fuel efficiency, reliability, and lower emissions.

2. By Cooling System
According to the cooling method, diesel engines are divided into air-cooled and water-cooled types. Water-cooled engines are more common in modern diesel generator sets because they provide better temperature control and are suitable for continuous operation.

3. By Air Intake System
Based on the air induction method, diesel engines can be naturally aspirated or turbocharged. Turbocharged engines deliver higher power output and improved performance, making them the preferred choice for most industrial generator applications.

4. By Number of Cylinders
Diesel engines are available in single-cylinder and multi-cylinder configurations. Multi-cylinder engines are widely adopted in commercial and industrial power generation due to their smoother operation and greater power capacity.

5. By Cylinder Arrangement
Depending on engine design, cylinders may be arranged in several layouts, including inline, V-type, horizontally opposed, and horizontal configurations. Each arrangement offers specific advantages in terms of engine size, balance, and power output.

6. By Operating Speed
Diesel engines can also be classified according to their rotational speed, typically as low-speed, medium-speed, or high-speed engines. The appropriate speed category depends on the intended application, load requirements, and operating environment.

Low speed range can be as low as 150 to 450 rpm for large size machines.

Medium speed can be from 600 to 1200 rpm for medium size machines.

High speed can be from 1500 to 1800 rpm for medium and small size machines.

Control Panel

The main purpose of control panel is to distribute the electric energy output by diesel generator set to users’ load or electric equipment through control panel.

Generally, it is equipped with voltmeter, ammeter, frequency and control switches related electrical equipments on the control panel. It aims to show the operation of the generator set and to maintain the voltage stability of the genset under the condition of load change.

Application of generating set

As self-contained power supply and standby power supply, diesel generator set has been widely used in communication base stations to guarantee the stability and reliability of power supply system.

Self-contained power supply: It is prepared as standby power supply when the power supply system blackouts. When the power supply interruption, the self-contained power supply will be put into the system immediately to work. It applies for the scene that needs less power.

Reserve power supply: It is also known as emergency power supply. Such power supply applies for the scene that power supply security requirement is relatively high.

Peaking power source: It is mainly used to make up for the shortage of electricity supply. It applies for the power cuts scene.

Portable power source: It is generally designed as the form of power vehicle. And it is mainly used for the mobile work scene. Some portable power source also share the nature of emergency power supply.

Common types of diesel genset

There are many types of diesel generator set, which can be divided into the following types according to its sructure, control mode and protection function.

1) Basic type genset

2) Automatic starting genset

3) Micro control automation genset

Working environment requirements of diesel genset 

Altitude: < 1000m

Ambient temperature: 5°C - 40°C

Relative humidity: <85% (25°C)

Longitudinal inclination when working: < 10°C

The engine room should be equipped with fire extinguisher. And maintainer and operator should know how to use it.