Selasa, 22 Maret 2011


When the main power outages (PLN), the required reserve supply of electricity and the generator-set conditions are expected to supply power mainly to priority loads. Generator can be used as an electrical backup system or "off-grid" (resources that depend on user needs). Genset is often used by hospitals and industries that require the resources steady and reliable (a high level of reliability of supply), and also to rural areas that do not have access to commercially supplied electricity through the existing distribution network PLN.

A diesel engine generator set consists of:
1. Pengerak prime mover or first, in this case diesel engine (in English called diesel engines)
2. Generator
3. AMF (Automatic Main Failure) and ATS (Automatic Transfer Switch)
4. Battery and Battery Charger
5. ACOs Panel (Automatic Change Over Switch)
6. Security for Equipment
7. Installing Power Supplies

Diesel Engine

Diesel engines including engines with internal combustion or motor fuel referred to, in terms of how to obtain thermal energy (heat energy). To generate electricity, a diesel engine connected to the generator in one axis (the axis of the diesel engine is coupled with shaft generator).

Advantages using diesel engines as prime movers:
* The design and simple installation
* Auxilary equipment (auxiliary equipment) simple
* When loading a relatively short

Losses on the use of diesel engines as early Mover:
* Weight machines are very heavy because it must be able to withstand vibration and high compression.
* Starting weight early, because the compression height of about 200 bar.
* The greater the power the diesel engine is the greater dimension, it caused trouble if the engine power is very big.
* Fuel consumption using fuel oil relatively more expensive compared to the power plants that use other fuel types, such as gas and coal.

How Diesel Engines Work

Prime mover or prime movers are devices that function to produce mechanical energy required to rotate the generator rotor. In the diesel engine / diesel engine ignition occurs alone, because the working process based on pure compressed air in the cylinder at high pressure (± 30 atm), so that the temperature inside the cylinder rises. And at that moment the fuel is sprayed in the cylinder temperature and high pressure exceeds the flash point fuel injected fuel will ignite automatically. The addition of heat or energy is always carried out at constant pressure.

Pressure fuel gas and combustion air will push piston is connected to the crankshaft using a piston rod, so the piston can move back and forth (reciprocating). Piston back and forth motion is converted into rotational motion by crank shaft (crank shaft). And vice versa crankshaft rotational motion is also converted into alternating piston movement in the compression step.

Based on analyzing how the system works, diesel motors can be divided into two, namely diesel motor that uses airless injection system (solid injection) were analyzed with a dual cycle and diesel engine that uses water injection system is analyzed with the diesel cycle (while motor gasoline were analyzed with
otto cycle).

The difference between diesel and gasoline engines is noticeable is located on the fuel combustion process, the gasoline motor fuel combustion occurs because of the fire jumps the electricity generated by two-electrode spark plug (spark plug), while in diesel combustion occurs because the increase in mixture temperature air and fuel due to compression piston until it reaches the flame temperature. Because the principle of the fuel ignition due to pressure of the diesel engine is also known as compression ignition engines, while motor gasoline spark ignition engine is called.

In diesel engines, piston do 2 short step towards the cylinder head at each power step.

1. The first step is a step above the entry and exploitation, here the air and fuel enter while the crankshaft rotates downward.
2. The second step is the compression stroke, the crankshaft continues to rotate causing the piston to rise and push the fuel, causing combustion. Both these processes (1 and 2) including the combustion process.
3. The third step is the expansion step and work, here the two valves of suction and exhaust valves closed while the crankshaft continues to rotate and withdraw the piston down.
4. The fourth step is the removal step, here the exhaust valve opens and causes the combustion gases due to residual waste out. Gas to get out because the process of this fourth piston moves up again upwards and causes the gas to exit. These last two processes (3 and 4) including the disposal process.
5. After the fourth process, then the next process will repeat again that the first process, where air and fuel re-entry.

Based on the above process will speed diesel engines can be classified into 3 parts, namely:
1. Low speed diesel (<400> 1000 rpm)

Starting the system or process to turn / run diesel engines are divided into 3 kinds of the starting system are:

1. Start System Manual
Start system is used to power diesel engines with a relatively small engine that is <30> 500 PK. This system uses a motor with high pressure air to start the diesel engine. How it works is by storing the air into an air bottle. Then the air is compressed so that the hot air and diesel fuel included in the Fuel Injection Pump and sprayed through the nozzle with high pressure. As a result there will be fogging and combustion in the engine. When the pressure inside the tubes down to the minimum limit, then the compressor will automatically raise the air pressure inside the tube until the pressure in the tube is adequate and ready to be used to make diesel engine starting.

AMF (Automatic Main Failure) and ATS (Automatic Transfer Switch)

AMF is a tool that functions reduce downtime and increase reliability of electric power supply system. AMF can control the transfer of Circuit Breaker (CB) or similar device, the main power supply (PLN) to the backup power supply (generator) and vice versa. And ATS is the complement of the AMF and work together.

How it Works AMF and ATS

Main Automatic Failure (AMF) to control the transfer of a device from the mains supply to the backup supply or the supply of reserves to supply utama.AMF will operate when the main power supply (PLN) is off by setting the backup power supply (generator). AMF can set the generator to operate if the mains supply from PLN dead and decided generator if the main supply from PLN alive again.

Batteries (batteries and batteries)

Battery is a process of converting chemical energy into electrical energy that is in the form of electric cell. Basically electric cell consists of two pieces of metal / conductor who differ dipped into the solution it will react chemically and produce electromotive force between the second conductor. Battery charging process is done by a current through the cells with the direction opposite the current flow in the discharge process so that the cell will be returned in its original state. Battery used in automated systems Genset serves as a source of DC current in starting the diesel.

Battery Charger

This tool serves for battery charging process by changing the voltage of 220V or from a generator PLN itself becomes 12/24 V using a rectifier circuit. Battery Charger is usually equipped with a safety short circuit (Short Circuit) in the form of fuses / fuse.

Panel ACOS

ACOs (Automatic Change Over Switch) is a generator control panel and there are several buttons that each have different functions.
Gen Set button automatic operation control, among others, namely:
Off, Automatic, Trial Service, Service Manual, Manual Starting, Manual stoping, Signal Test, Horn Off, Release, Start, Start Fault, Engine Running, Supervision On, Low Oil Pressure, Temperature To High, Over Load Generator.

Safety System Genset

The security system must be able to work quickly and accurately isolate the disturbances in order to avoid fatal damage. Protection on the engine generator there are two kinds:
1) Security alarm
Aims to inform the operator that something is not normal in the operation of the engine generator and for operators to act immediately.
2) Safety trip
Serves to prevent the engine from possible damage to the generator because there system is not functioning normally the engine will stop automatically.
Type of trip safety, among others:
1) Round more (over speed)
2) high cooling water temperature
3) low lubricating oil pressure
4) Emergency stop
5) Reverse power

Earthing (grounding)

a) Grounding the system, earth to a point in the conductive flow of the system. In general point is a neutral point of a machine, transformer, or to a particular electrical circuit.
b) Grounding system equipment, grounding for a part that does not carry current from the system, for example: All the metal as a cable channel, frame machines, rod holders of the switch, the switch box cover.

Safety relays on generators:

a) overcurrent Relay
Thermal Over Load Relay (TOLR) is used to protect motor and motor control equipment from damage due to overload or the subsequent inter-conductor short-circuit that led to a net or inter-phase.
b) Relay overvoltage
work produced by the generator when the voltage exceeds the nominal.
c) Differential Relay
work on the basis of the comparison voltage or current ratio, ie the amount of current before the stator windings with current flowing in the conductor leading to the nets.
d) turning the power relay
serves to detect the active power flow into the generator.


serves to secure the equipment or electrical installation of short circuit fault
If a fuse on top of current flow bypassed his office, then at a certain time the fuse will melt (end). The amount of current that can melt a fuse within 4 hours of work divided flow is called fusion factor ranging from 1 to 1.5.

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