For our example of an electrical power generation unit we will look at a diesel powered, a mobile, trailer mounted system. There are various components that constitute the system and their functions explored.
Parts & Functions of a Diesel Generator
Engine: The ideal engine will be simple and reliable, as compact as possible, with low noise, emissions levels and user friendly. Most overhead valve (OHV) engines provide these advantages. The intake and exhaust valves are located in the head and most modern engines; gas, diesel or multi-fuel engines are of this design. CIS or cast iron sleeves are an integral part of any quality engine.
Alternator or ‘Genhead’: This is the electrical generator part of the unit, converting the rotating power from the engine input to electrical output.
Stator: The stator is a stationary component with electrical conductors wound over an iron core. The rotor or armature is the rotating component that produces a magnetic field, by using field through induction or incorporating a permanent magnet. Induction systems utilize a DC current to energize the magnet. As the rotor either rotates around the stator or enclosed by the stator the magnetic field induces a voltage difference in the windings of the stator producing an alternating current.
Fuel & Fuel Lines: To cut down on servicing the generator must have sufficient fuel to run about 8 hours or more. The unit is equipped with fuel lines to supply the fuel pump which pressurizes the fuel prior to injection inside of the engines cylinder, common to most modern diesel engines.
Vents, Overflow Lines & Water Fuel Separators: There are also vents, overflow lines and water-fuel separators as well.
Voltage Regulators or Exciter Windings: A means of converting a portion of the AC power to DC power is incorporated to produce the direct current for charging the starting system batteries and supplying power to the rotor. This is done by voltage regulators or exciter windings connect to rotating rectifiers.
Lubrication Systems: All systems have a lubrication system both in the engine and lubrication for the genhead bearings.
Heat Exchanger & Radiator: Most diesels are liquid cooled though there are large stationary units that may circulate hydrogen through a heat exchanger. For efficient cooling the radiator needs access to fairly large volumes of moving air. Exhaust systems need to reduce running noise in compliance with local regulations.
DC Power: DC power for startup can be supplied either by the generator DC system or a separate automotive type alternator externally mounted on the engine.
Governors: The engines run on governors that regulate fuel flow according to the load. It is important that engine speed remain at a constant speed to produce the 60 Hz alternating current used in North America.
Control Panel & Output Meters: Lastly some means of starting, stopping and controlling running operations is incorporated into a control panel. This panel either utilizes an LED, liquid crystal or analog output meters to monitor the functions of the unit. Both engine and generator output gauges and controls are used to for feedback of operations and to provide fine tuning of the system.
Enclosure: The enclosure is insulated to reduce noise and moderate the internal environment from the weather. It protects the engine from weather and wind debris.
Engine air filters: These remove particulates that maybe detrimental to the systems operation.
Household systems operate on a 120 or 240 volt single phase. But many industrial operations require 3-phase power at 408 volts. Compressors, powered machinery are all geared to triple phase power supply. An effective generation system needs to be a multi-phase/voltage unit to be utilized in varying conditions and requirements.