What is a diesel generators main components?
Diesel generators are made from lots of different parts. The main parts are:
- Diesel Engine including
- Fuel System
- Lubrication System (oil system)
- Cooling System
- Electrical System
- Exhaust System
- The turbo charger
- AC Alternator containing
- Main Rotor
- Main Stator
- Automatic Voltage Regulator (AVR)
- Exciter Stator
- Exciter Rotor
- Radiator with
- The radiators frame
- the radiators core
- A top tank / expansion tank
- An intercooler
- Base Frame or Base Tank
- Control Panel containing
- Control Module
- Terminal Rail
- Current Transformer
- A Circuit Breaker
The diesel engine
The diesel engine is the workhorse in the generator. It provides the power to turn the AC alternator.
The engines fuel System
The fuel system includes the fuel injection pump, the lift pump, the injectors and all the fuel pipes. There will also be some fuel filters and maybe a water separator preventing poor quality fuel from damaging your diesel engine.
The engines lubrication system / oil system
The lubrication system keeps your engine running smoothly, preventing the moving parts from wearing by using the oil under pressure to lubricate and reduce friction. The oil system will have an oil pump and oil filters to keep the oil clean from containments.
The engines cooling system
The cooling system handles the engine coolant - normally a mixture of distilled water and glycol with some additional additives to help prevent corrosion. There may also be a coolant filter on some engines and a "water pump" which is actually a coolant pump. The coolant pump is used to push the coolant round the engine and whichever device is used to cool the liquid - usually a radiator, but sometimes a heat exchanger.
The engines exhaust system
Getting rid of the waste combustion gas is very important - moving the waste gas from the engines cylinders out through the exhaust manifold to the main muffler system that reduces the noise. The muffler isn't usually part of the engine, but an addition to reduce the noise to the customers requirements. The exhaust gas will pass through the turbo-charger to make it spin where one is fitted.
The engines Turbo charger
Most engines will have a turbo fitted. This device compresses the combustion air to make the engine more powerful.
The AC Alternator
The AC alternators main rotor
Part of the excitation system, the main rotor is connected to the engine and spins a magnetic field inside the main stator, to generate a voltage.
The AC alternators main stator
The automatic voltage regulator
The automatic voltage regulator, or AVR monitors and controls the voltage in the generator. It sends power to the exciter stator and adjusts it to keep the voltage at the main rotor at a preset level.
The AC alternators exciter stator
The exciter stator takes power from the AVR and induces a current in the exciter rotor.
The AC alternators exciter rotor
A radiator is usually fitted to the generator (if not an alternative method of cooling must be used). The heat generated as the engine runs is taken away by the engines coolant and the radiator fan blows air through the core, cooling the engine.
The radiators frame
The frame supports the radiators core as the fan blows air through it and the engine frame vibrates as it runs.
The radiators core
This is where the cooling happens. The core is made up of tubes and fins. Coolant flows through the tubes and the heat transfers to the fins. The air blown by the fan moves this heat away from the generator.
The Radiators fan (or fans)
The fan does the work, it can be mechanically powered from the engines crank shaft via pulleys and belts, or it could be electrically driven by an electric motor. There can be multiple fans on a radiator, especially when they are electrically driven.
The expansion tank / top tank
The expansion tank is where you can check the coolant level and to it up. There is space for the coolant to expand and sensors, such as a low coolant level sensor can be found fitted here.
The intercooler is essentially a second radiator core - except instead of cooling the coolant that flows round the engine, it is used to cool the combustion air after it has been through the turbocharger. This air becomes more dense as it cools and helps to improve combustion and available power.
Base frame or Base tank
The base frame or base tank holds the weight of the diesel engine and alternator. A fuel tank may be found in the base, especially on smaller diesel generator models. You may also see anti-vibration mounts on the base frame, which help to prevent the vibration being transmitted to the frame when the engine is running.
Generator Control Panel
Providing monitoring, protections and control, the generator control panel is the brains behind the magic. The control panel monitors the engine and alternator and ensures everything is running correctly. It can also provide synchronising to enable running in parallel.
The control module
The control module is the heart of the panel. This electronic module is essentially a small PLC, taking in the electrical signals and deciding what to do next. These are usually programmable to achieve different outcomes for different applications.
The terminal rail
The terminal rail - not always fitted but generally useful. it is a connection point for all the cables coming from the engine and alternator, these are then connected to the control module. Equally outputs from the control module are taken to the terminal rail and then fed to the engine and alternator. Fuses or small circuit breakers are often found on the terminal rail and act as protection devices.
Current transformers are used to convert the high current output of the alternator to a lower current for monitoring. Sensitive electronics in the control module cannot monitor directly the huge currents coming from the alternator terminals. Typically current transformers convert the current to a 0-5A range for monitoring.
A circuit breaker
the main output breaker - not always found in the control panel - it can be separate and free-standing on large units. The circuit breaker is used to stop the flow of current in the case of overload or short-circuit.