What is a diesel Genset?

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Modern society is inseparable from electricity. From wi-fi and communications to lighting and climate control, businesses and homes need a stable power supply to function properly.

The generator set can add an extra layer of safety in the event of a power outage or blackout. Back-up generators can keep critical systems in medical facilities, businesses, and homes running in case the utility power is interrupted.

A generator set or “generator set” is a portable device consisting of an engine and an alternator/generator to provide energy. Generating sets are often used in developing areas and other areas that are not connected to the power grid; places where power outages are frequent; and/or where power outages may cause particularly serious or dangerous problems, such as in deep mines. They can be used as main energy sources or auxiliary power sources, perhaps during peak usage hours.

A diesel generator (DG) (also called a diesel Genset) is a combination of a diesel engine and a generator (usually an AC) to generate electrical energy. This is a special case of engine generators. Diesel compression ignition engines are usually designed to run on diesel fuel, but some types are suitable for other liquid fuels or natural gas.

Diesel generator sets are used in places that are not connected to the grid, or as an emergency power source when the grid fails, and for more complex applications such as peak shaving, grid support, and output to the grid.

The proper size of diesel generators is essential to avoid low loads or power shortages. Due to the characteristics of modern electronic products, especially non-linear loads, size adjustment becomes complicated.


A genset is a combination of a prime mover (usually an engine) and an alternator. The engine converts the chemical energy of the fuel into mechanical energy. This mechanical energy is used to rotate the alternator rotor; the mechanical energy is converted into electrical energy. The alternator consists of two main parts; the rotor and the stator. The alternator rotor is rotated by the magnetic field between the rotor and the stator, and a voltage is generated on the alternator stator through electromagnetic induction. When the voltage on the stator is connected to the load, current flows and the generator produces electricity.

In short, generator sets have created portable energy sources. When a generator is used in combination with a diesel engine, to give just one example, this will create a diesel generator set.


A diesel generator set usually has the following components:

(1)Engine/motor. The main component of a generator set, which runs on fuel. A good engine is strong enough to meet the needs and functions under adverse conditions (ie, bad weather).

(2)Alternator. This component converts mechanical energy into electrical energy; without it, there is no power.

(3)control Panel. It acts as the “brain” of the generator set, controlling and regulating all other components.

(4)Fuel System. The assembly consists of a storage tank and hoses that deliver fuel to the engine.

(5)Voltage Regulator. This controls the amount of voltage generated by the generator set and converts AC current to DC current.

(6)Base frame/shell. The base frame supports the generator and fixes the components together. It can also be used as an anti-vibration and grounding system, and may or may not hold a fuel tank. It can be mounted on wheels to make it easy to carry.

(7)Drawstring mechanism or battery. An initial spark is required to start the combustion process of the portable generator. This usually happens through a wire-pull mechanism (such as a lawn mower) or a starter motor powered by a DC battery.

(8)Manual or automatic transfer switch. The transfer switch directs power between the main power source (utility power source) and the auxiliary power source (generator). This keeps the current consistent and prevents dangerous interruptions.

(9)Baffle box or enclosure. The container is usually made of stainless steel, which reduces noise, prevents corrosion and promotes airflow to cool the engine.

The generator does not require intensive maintenance, but it is important to understand its internal mechanism. This way, you can perform preventive and general maintenance as needed, while knowing how to order replacement parts.


Set sizes range from 8 to 30 kW (also 8 to 30 kVA single-phase), suitable for homes, small shops and offices, while larger industrial generators range from 8 kW (11 kVA) to 2,000 kW (2,500 kVA three-phase) ) Used in large office complexes, factories and other industrial facilities. A 2,000 kW unit can be installed in a 40-foot (12 m) ISO container, which contains fuel tanks, control devices, power distribution equipment, and all other equipment required to operate as an independent power station or as a backup power source for the grid. These devices are called power modules and are generator sets mounted on large three-axle trailers weighing 85,000 pounds (38,555 kg) or more. The combination of these modules is used in small power stations. Each power section may use 1 to 20 units. These sections can be combined into hundreds of power modules. In these larger sizes, the power modules (engine and generator) were taken to the trailer site and connected together by large cables and control cables to form a complete synchronous power plant. There are also many options to meet specific needs, including control panels for automatic startup and mains parallel connection, soundproof enclosures for fixed or mobile applications, ventilation equipment, fuel supply systems, exhaust systems, etc.

Diesel generators are not only used for emergency power, but may also have auxiliary functions to supply power to the utility grid during peak periods or during shortages of large generators.

Ships usually also use diesel generators, sometimes not only to provide auxiliary power for lights, fans, winches, etc., but also indirectly for main propulsion. With electric propulsion, the generator can be placed in a convenient location to allow more cargo to be carried. Electric drives for ships were developed before the First World War. Many warships built during World War II designated electric drives because the manufacturing capacity of large reduction gears was in short supply compared with the manufacturing capacity of electrical equipment. This diesel-electric arrangement is also used in some very large land vehicles, such as railway locomotives.

When the diesel generator set runs under its design conditions, it has higher efficiency and longer service life. However, it is important to understand the difference between kilowatts (kW), kilovolt-amperes (kVA), and power factor (PF):

Kilowatts (kW) are used to measure the actual power provided by generators, which are used directly by electrical appliances and equipment in buildings.

The kilovolt-ampere (kVA) measures apparent power. This includes active power (kW) and reactive power (kVAR) consumed by equipment such as motors and transformers. Reactive power is not consumed, but circulates between the power source and the load.

Power factor is the ratio of active power to apparent power. If the building consumes 900 kW and 1000 kVA, the power factor is 0.90 or 90%.

The nameplate of the diesel generator has ratings of kW, kVA and PF. However, the operating conditions are determined by the connected load, not by the generator. To ensure that your building has a suitable generator set, the best advice is to have a professional electrical engineer determine the size of the generator set.


Diesel fuels are named after diesel engines; diesel engines are only compression-ignition engines and can use a variety of different fuels, depending on configuration and location. Where it is possible to connect to a gas grid, gas is usually used because the gas grid will remain pressurized during almost all power outages. This is achieved by introducing gas into the intake air and using a small amount of diesel for ignition. It can be immediately converted to 100% diesel fuel operation.

In more rural situations, or for factories with low load factors, diesel oil extracted from crude oil is a common fuel; it is less prone to freezing than heavy oil. Endurance will be limited by the size of the fuel tank. Diesel engines can use a variety of crude oil distillates, from natural gas, alcohol, gasoline, wood gas to fuel oil, from diesel to cheaper residual fuels similar to lard at room temperature, and must be heated to enable it to follow the fuel The pipeline flows down.

Larger engines sometimes use heavy oil, mainly tar, from the end of the refining process. Keeping the fuel oil heated to make it flow, while reducing the risk of fire caused by overheating of the fuel, adds a slight complexity, which makes these fuels undesirable for smaller, usually unmanned power plants.

Other possible fuels include biodiesel, pure vegetable oil, animal fat and tallow, glycerin, and coal water slurry. These should be used with caution: due to their composition, they usually have an adverse effect on engine life.

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