Generators are useful devices that supply electricity during power outages and prevent daily outages or disruption to business activities. Generators are available in a variety of electrical and physical configurations for use in a variety of applications.
The following is how the generator works, the main components of a generator and how the generator works as a secondary source of electricity in residential and industrial applications.
How a generator works
An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as output. It is important to know that a generator does not actually generate electrical energy, instead a generator of mechanical energy supplied It uses the transfer of electrical charges in its coil through an external electrical circuit, which circulates the output current supplied by the generator.
This mechanism can be understood by considering that the generator is similar to a water pump. That is as it pumps the water to flow throws but really flow of water through it is not created, generators modern on the principle of induction Altrv magnet in the years 1831 and 1832 by Faraday’s discovery, work, Faraday discovered By moving an electrical conductor, such as a wire containing an electric charge, a higher electric current can be created in a magnetic field , which creates a potential difference between the two ends of a wire or electrical conductor, which in turn causes a current to flow. Falling electrical charges and thus generating electricity.
The main components of a generator
The main components of an electric generator can be broadly classified as follows: (see image above)
- Alternating or alternating current generating device
- Fuel system
- Voltage regulator
- Cooling and exhaust systems
- Lubrication system
- Battery charger
- Control panel
- The main set or frame
The description of the main components of the generator is given below:
1- Generator motor
The source of mechanical energy is the input to the generator. The size of the motor is directly proportional to the maximum output power of the generator that it can supply.
There are several factors to consider when evaluating a generator motor.
Consult the engine manufacturer for complete engine specifications and maintenance plans.
Type of fuel used by the generator
Generator engines run on a variety of fuels such as diesel, gasoline, propane (in liquid or gaseous form) or natural gas.
Smaller engines usually run on gasoline, while larger engines run on diesel, liquid propane, propane gas or natural gas.
Some engines can also run on dual diesel and gas in dual-mode operation.
OHV motors compared to non-OHV motors
OHV engines are different from other engines in that the inlet and outlet valves of the engine are placed at the head of the engine cylinder.
OHV motors have several advantages over other motors, including:
Simpler mechanism of action
Longevity and permanence
User friendly in operation
Low noise in operation
Low emission levels
However, OHV engines are more expensive than other engines.
Cast iron sleeve or liner (CIS) in the engine cylinder
CIS is lined on the engine cylinder. So that it reduces wear and tear and ensures the durability of the engine.
Most OHV motors are equipped with CIS, but it is necessary to check this feature in the generator motor.
CIS is not an expensive feature, but it plays an important role in engine durability, especially if you need to use the generator often or for a long time.
2- Alternating power generating device
It is part of the generator that generates electrical output from the mechanical input supplied by the motor. Which consists of a set of fixed and movable parts placed in a chamber.
The components work together to cause relative motion between magnetic and electric fields, which in turn generate electricity.
- a. Stator
This component is fixed. It consists of a set of electrical conductors placed in coils on an iron core.
- b. Rotor or armature
It is a moving component that produces a rotating magnetic field in all three ways:
- Induction: These are known as brushless rotations and are commonly used in large generators.
- With permanent magnets: which is common in small rotating units.
- Using an actuator: An actuator is a small source of direct current (DC) that energizes the rotor through a set of conductive slip rings and brushes.
The rotor creates a moving magnetic field around the stator, thus inducing a voltage difference between the stator windings, which produces the alternating current (AC) output of the generator.
The following factors should be considered when evaluating an AC generator or alternator generator:
Metal chamber compared to plastic chamber
An all-metal design ensures the durability of the alternator.
Plastic containers deform over time, leaving the moving parts of the alternator unprotected.
This increases wear and tear and, most importantly, is dangerous for the user.
Ball bearings compared to needle bearings
Ball bearings are usually more preferred and more durable.
An alternator does not use a brush so it requires less maintenance.
3- Fuel system
Usually the fuel tank has enough capacity to continue the operation of the generator for 6 to 8 hours on average.
In the case of small generator units, the fuel tank is part of the generator base or is mounted on top of the generator frame.
Commercial applications may require the construction and installation of an external fuel tank.
Common features of the fuel system are:
- Pipe fittings from fuel tank to engine
The supply line transports fuel from the tank to the engine and the return line transports fuel from the engine to the tank.
- Ventilation pipe for fuel tank
The fuel tank has a vent pipe to prevent pressure or vacuum during filling and emptying the tank again.
When refilling the fuel tank, make sure there is a metal-to-metal connection between the filler nozzle and the fuel tank to prevent sparks.
- Overflow connections from fuel tank to drain pipe
This is necessary so that any overflow does not cause liquid leakage in the generator set when refilling the tank.
- Fuel pump
Which transports fuel from the main storage tank to the day tank. The fuel pump normally operates electrically.
- Water separator from fuel or fuel filter
Separates foreign matter and water from liquid fuel to protect against corrosion and contamination of other generator components.
- Fuel Injector
Which converts liquid fuel into powder and sprays the required amount of fuel into the engine combustion chamber.
4- Voltage regulator
This component, as its name implies, regulates the output voltage of the generator.
This mechanism is described below with each component that plays a role in the voltage regulation cycle process:
Voltage regulator: Convert AC voltage to DC current
The voltage regulator injects a small portion of the output of the AC voltage generator and converts it to DC current.
The voltage regulator then transmits this DC current to a set of secondary windings in the stator, also known as actuator windings.
Actuator windings : Convert DC current to AC current
The actuator windings now act like the original stator windings and produce a small AC current.
Actuator windings are connected to units known as “rotary rectifiers”.
Rotary rectifiers: Convert AC current to DC current
Which rectifies the AC current generated by the actuator windings and converts it to DC current.
This DC current is fed to the rotor / armature to create an electromagnetic field in addition to the rotating magnetic field of the rotor / armature.
Rotor or armature: Convert DC current to AC voltage
The rotor / armature now induces a larger AC voltage across the stator windings.
The generator now produces a larger output voltage AC.
This cycle continues until the generator begins to generate an output voltage equal to its total operating capacity.
As the output of the generator increases, the voltage regulator produces less DC current.
When the generator reaches its full operating capacity, the voltage regulator reaches equilibrium and generates enough DC current to keep the generator output at the full operating level.
When a load is added to the generator, its output voltage decreases slightly.
This causes the voltage regulator to operate and the high cycle begins. This cycle continues until the generator output gradually reaches its main operating capacity.
5- Cooling and exhaust systems
- cooling system
Continuous use of the generator causes its various components to start heating.
It is necessary to have a cooling and ventilation system in order to release the heat generated in this process.
Raw or fresh water is sometimes used as a coolant for generators, but these are mostly limited to certain situations, such as small generators in urban applications or very large units of 2250 kW and above.
Hydrogen is sometimes used as a coolant for the stator windings of large generator units because it is more efficient at absorbing heat than other coolers.
Hydrogen removes heat from the generator and transfers it through a heat exchanger to a secondary cooling circuit that contains non-mineral water as a coolant.
This is why very large generators and small power plants often have large cooling towers nearby.
For other common applications, both residential and industrial, a standard radiator and fan are mounted on the generator and act as the main cooling system.
It is essential to check the cooling levels of the generator daily.
The cooling system and raw water pump should be washed after every 600 hours and the heat exchanger should be cleaned after every 2400 hours of generator operation.
The generator should be placed in an open and ventilated environment that provides enough fresh air.
The National Electricity Act, or NEC, states that a minimum distance of 3 feet is allowed around the generator to ensure the free flow of cooling air.
Exhaust fumes emitted by a generator are just like the exhaust fumes from any other gasoline or diesel engine and contain highly toxic chemicals that must be properly managed.
Therefore, it is necessary to install a suitable exhaust system to expel the exhaust gases.
Exhaust pipes are usually made of cast iron, iron or steel.
In order to minimize vibrations and prevent damage to the generator output system, the output pipes are usually connected to the motor using flexible connections.
Exhaust or exhaust pipe ends outside.
Make sure that the generator output system is not connected to any other equipment.
6- Lubrication system
Because the generator contains moving parts in its engine, it needs lubrication to ensure durability and uniform operation over a long period of time.
The generator motor is lubricated with oil stored in the pump.
The lubricating oil level should be checked every 8 hours for generator operation.
You should also check for any lubricant leaks and change the operation of the lubricating oil generator every 500 hours.
7- Battery charger
The starting function of a generator is battery operated. The battery charger charges the generator battery with an accurate buoyancy voltage.
If the buoyancy voltage is too low, the battery will remain uncharged.
If the buoyancy voltage is too high, it will shorten the battery life.
Battery chargers are made of stainless steel to prevent corrosion.
They are also fully automatic and do not need to change settings.
The DC voltage output from the battery charger is set at 2.33 volts per cell, which is the exact buoyancy voltage for lead batteries.
The battery charger has a separate DC voltage output.
8- Control panel
This is the user interface of the generator and contains regulations for electrical outputs and controls.
9- The main set / frame
All generators, portable or fixed, have custom enclosures that provide support for the structure base.
The frame also allows the generator to be grounded for safety.
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