Energy cannot be created nor can it be destroyed, but energy can be converted to other forms of energy. For example, electrical energy can be converted into motion energy through an electric motor, and vice versa energy can also be converted to electrical energy through a generator.
Then, what is the explanation of electric generators and how can electric generators work to convert motion energy to electrical energy? see more in this article.
Definition and Function of Electric Generator
The generator is an electronic device that functions to convert input in the form of kinetic energy into electrical waves that take place continuously or once against input.
The waves that are reunited will cause a potential difference so that an electron flow will form from the negative pole to positive. This is what we know as electrical energy.
The functions of the generator are several types, namely;
- In general generators are used to produce electrical energy for power sources of circuits that require electricity
- The generator is also used as a tool to detect the frequency of a kinetic motion.
- In some measuring instruments, the working principle of a generator is used to measure a movement.
Energy sources of generators, come from various kinds. The easiest example of a power plant, the source of energy comes from a windmill that is driven by wind energy or water.
While on vehicles, generators are referred to as altenators because they produce AC currents. The source, comes from the rotation of the engine itself.
Types of electric generators
1. When viewed from a magnetic field
- Inner pole generator; has a magnetic field located inside, exactly a rotor that will emit a magnetic field.
- Outer pole generator; has a magnetic field outside (covering rotot), or in other words a stator that will emit a magnetic field.
2. When viewed from the current that is raised
- AC generator; generator that generates alternating electrical energy (AC)
The working principle
of an AC generator
The working principle of an AC generator (alternating current) refers to Faraday’s Law. In Farday’s law it is stated, that if a conductor is in a changing magnetic field and cuts the magnetic force line, an electromotive force is formed at the end of the conductor. Then the results of the electromotive force are called GGL and have Volt units. The amount of voltage produced by a generator depends on the speed of rotation, the number of turns that cut the fluk, the amount of magnetic flux that is generated by the magnetic field, and the construction of the generator.
- DC generator; generator that generates direct electricity (DC)
The working principle of a DC generator
Basically the working principle of a DC generator is almost the same as an AC generator. But the induced current on the DC generator does not change because it uses a commutator.
You need to know that electric machines are grouped into 3 types, namely
- Electric generator,
- Electric motors and
The three types of tools are of course different functions,
electric generators are electrical machines that function to produce electrical
energy by changing mechanical energy (motion).
Then the electric motor functions as a transformer of electrical energy into motion energy while the transformer is a transfer of electrical power whether it is step-down or step-up.
Today I do not discuss the three types of tools but only in general. If you already understand, please ignore this article, the electricity generator was originally from the theory by an English scientist, Michael Faraday.
“If a conductive wire is moved to cut the Flux / magnetic field, then on the wire there will be an Electric Motion Style”, from the theory it was developed to make a generator.
Working Principle of Electric Generator:
The working principle of an electric generator now and generally, is the movement of the magnetic field on the rotor against the fixed coil on the stator.
The magnetic field is generated by giving a DC (Direct Current) voltage to the field amplifier coil on the rotor. Both those produced from the amplifier itself and separate amplifiers.
For the amplifier itself can be generated by the voltage and the current itself generated by the stator coil. For stator coils this electric generator depends on the manufacturer.
It can be designed with a 3 phase system or a 1 phase system with AC = Alternating Current. The resulting AC voltage must be made into a DC voltage by a series of rectifier diodes or slip-rings flowing to the magnetic field amplifier coil.
The electric generator with its own amplifier is always designed with AVR (Automatic Voltage Regulator) which functions as a stator output voltage controller. If the expected limit is 220 Volts or 380 Volts, the AVR will control the size of the current and voltage entering the coil on the main amplifier (Main Exciter), and will continue to channel DC voltage to the field amplifiers through the slip ring or rectifier diodes. .
AVR is not designed for frequency stabilizers, because the frequency is obtained from the rotor rotation. If the electric generator is a diesel engine then there must be an engine speed stabilizer. Although the generator load is relatively not fixed, by adjusting the fuel supply on the diesel engine or other equipment.
For example ELC (Electronic Load Controller) / DLC (Digital load Controller) on synchronous generators or governor systems in PLTMH (Tenagan Micro Hydro Electric Center).
For electric generators with separate amplifiers by supplying DC voltage from the outside of the generator. For example, from a rectifier system from the outside which is flowed to the magnetic field amplifier coil.
However, the type of generator with a separate amplifier may not be on the market due to ineffectiveness.
1. Stator (permanent magnet)
Stator is a component that is tasked with producing a magnetic field, as the name implies the stator is silent (static). This stator has an air gap that has a magnetic gap.
2. Rotor (copper wire coil)
The rotor is a coil that is wrapped around a core or iron core located in the air gap in the stator. This rotor is rotating in the middle of a magnetic field.
As explained above, the rotor is a coil that rotates while the stator is a stationary magnetic field. The location of the rotor is right in the middle of the magnetic field formed on the stator.
When there is energy that rotates the rotor, that’s where the magnetic force lines intersect the coil. So, there will be a potential difference between the two poles of the coil. This is what causes electricity.
Where is this electricity going?
To find out the direction of electricity, we can follow the right hand flemming method or lorentz law about the relationship between force, magnetic field and the direction of the electric charge.
Seen in the picture that the thumb shows the direction of movement of the coil, the index finger shows the direction of the magnetic field (from U to S), while the middle finger shows the direction of the electric current.
What is the difference between an AC and DC generator
From the name alone it is clear that the electric current produced by these two types of generators is different. However, if discussed more specifically where is the difference between the construction of AC and DC generators?
1. Construction of an AC Generator
In general, the two generators have exactly the same construction. But there is a slight difference in the end area, precisely on the connection between the coil and the output cable.
In a simple generator coil, there are two cables that function as positive and negative cables.
The AC generator uses two slip rings that are connected to each end of the coil. This design makes the two ends of the coil not touch each other (only connected with one slip ring continuously).
So that when the coil is spinning, there will be an alternating current flow because it matches the flemming method, the movement on one side of the coil will go up and down (when rotating). This is what causes the end of the coil to act as a positive and act as a negative.
2. Construction of a DC generator
While the DC generator also has a coil with two ends (positive end and negative end). But there is no slip ring, but there are two brushes located on the left and right.
Brush A acts as a positive brush because on this side, the current flowing is only in the same direction. While brush B acts as a negative brush.
The difference is that with an AC generator, the two ends of the coil alternately will touch both brushes. So, the negative and positive currents will be separated by these two brushes, so that there is a direct flow of electricity.
Application of Electric Generators in Life
Generators are often used in several components such as the following;
- PLN power plants, with any input energy used to remain at the end using a generator.
- Altenator on cars, its function is to convert some engine parts into electrical energy to supply the vehicle’s electricity needs.
Benefits of Emergency
Electricity loss can be a problem.
Power failure can take several minutes to several weeks, depending on the cause and configuration of a power outage. These events can appear with or without warnings and can bring problems in the case of inoperable business and mechanical failure. Food can be damaged in a warm refrigerator and the basement can flood without a waste stream. Having an emergency backup generator prevents you and your business from suffering this inconvenience and loss of income.
Electricity is vital.
Electrical power is needed by medical facilities such as hospitals and doctors’ offices to access them so they can continue to care for patients. A person’s life can be at stake if emergency scanning and tests are not available because the facility has no electricity. Heating and cooling, lighting systems and life support machines, everything will disappear without this generator. Commercial and major businesses also began to buy emergency backup generators to prevent loss of customer contact due to electrical disruptions.
Permanent standby generator is a backup power system that is installed as part of the facility’s power cable.
The backup generator will automatically activate after a power outage, and turn itself off after the main utility power source is returned to the facility. This is usually a high ranking option if your facility is in an area that often loses electricity because it allows you to keep your vital equipment running. Many businesses are not able to wait for a power outage. For this reason, many companies choose to prepare by installing the right type and capacity of the generator to protect their companies and investments from huge losses. This permanently installed emergency power source operates at an existing fuel source facility, be it diesel or natural gas. If you don’t have one of these fuel lines yet, you can install a liquid propane tank. The size, ampere, and output of watts from the emergency backup generator will depend on the power capacity needed for what facilities and equipment to run (both heating and cooling, lighting, etc.). The stronger they are, the more combinations of outlets are possible. Usually, emergency generators come with standard duplex 120 volts, 15 amp outlets. When power increases, more channels are available.
Spikes and watt recognition.
When choosing the best emergency backup generator for your facility, it’s important to think about wattage recognition and wattage surges. A surge in wattage is how many watts are needed to start the equipment. The wattage is the amount of power needed to keep the device running. Combing these two numbers determines the number of watts that is most appropriate for your facility. After identifying how many watts are needed during a power outage, you can start choosing different types or sizes of generators. It is recommended to install a transfer system to allow a secure connection from the generator to the electrical circuit facilities.