We have already dealt with this topic in a previous article on generators or generator sets, but this time we will detail a little more the technical aspect of these important machines.
The generator sets they can generate power anywhere it is required and at any time. These teams work based on a non-renewable energy source, but represent a wide range of powers. Basically they have a thermal engine, whether gasoline, diesel or other; coupled to an electric current generator, which allows the chemical energy available in the fuel to be converted into rotational mechanical energy in the thermal engine and finally, said energy is used by the generator to obtain electrical energy.
Role and importance of generators
The main function of the generators is to provide electricity in those places where there is no standard supply of said service, such as remote and sparsely inhabited areas. And they are also used in those places where the failure of the electrical service can cause considerable damage, so they use a generator in an emergency. Some examples of these places are hospitals, factories, social institutions, food industries, communications industry, among others.
The importance of generator sets lies mainly in the fact that being an alternative energy source, they avoid or minimize severe disorders in the integrity of people and in the production of certain items, when the traditional supply of electricity fails or does not exist.
In addition, many times it is impossible to provide energy at the workplace, in these cases, the generator or generator set is the complement, for example, of a welding team.
Parts or components of a generator or generating set
A generator or generator set is made up of the following elements:
- The engine is the mechanical power source that allows the alternator to generate electricity. There is a gasoline engine and a diesel or diesel engine. The latter is the most used, due to its mechanical, ecological and economical presentation. Some adaptations have emerged that allow the use of gas.
- The motor governor is a device designed to maintain a constant speed of the motor, depending on the load requirements. Engine speed is directly related to the alternator output frequency, so any variation in engine speed will affect the output power frequency.
- The engine electrical system can be 12V or 24V, negative ground. It includes an electric starter, battery or batteries, and sensors/alarm devices. Generally, an engine has an oil pressure manocontact, a temperature thermocontact and a contact in the engine charging alternator, which allows detecting a charge fault in the battery.
- The engine cooling system can be water, oil or air based. Water or oil cooling consists of a radiator and an internal fan to cool its own elements. Air cooling consists of a large fan that circulates cold air around the engine, to cool it.
- The alternator is the component through which the output of electrical energy is generated. It is generally splash-protected, self-regulating, brushless, and precision-coupled to the motor. There are also alternators with brushes, for generators whose operation will be limited or forced to major work.
- The bench and the fuel tank. The bedplate is usually made of high-strength steel and is what the engine and alternator are attached to. This bench also includes the fuel tank, which must have a standard capacity of at least 8 hours of operation at full load for emergency use. In case of continuous use, reserve tanks must be available.
- Vibration isolation consists of anti-vibration pads designed to minimize vibrations generated by the engine and alternator. They are generally located between the base of the engine, the alternator, the control panel and the base.
- The silencer is installed on the engine to minimize noise emission.
- The control system allows to monitor and control the operation of the generator, to avoid possible failures.
- The output automatic switch allows to protect the generator with manual control. The alternator is also protected with contactors.
Other additional devices or components for generators:
- The electronic card is used to automatically regulate the speed of the motor. This board controls the “pickup” input signal and the “actuator” output signal. The main idea is to control the speed of the motor so that sudden accelerations do not occur and the power of the motor is generated continuously.
- The transfer pump is used to automatically replenish the generator fuel. This consists of an engine with a coupled pump, which is responsible for providing the fuel to the tank. A buoy indicates the maximum and minimum level, when the minimum level is marked, it activates the transfer pump.
- The preheating resistance is a heating device, in charge of maintaining the adequate temperature of the generator, when it is in a cold environment. For air-cooled generator sets, an electric radiator located under the engine is often used to keep the oil at a suitable temperature. In water-cooled generators, the preheating resistance is installed in the cooling circuit to heat the engine cooling water. This preheating resistance has an adjustable thermostat.
Generators are equipment of great utility and importance for some social and industrial sectors, which is why over time they have advanced in design and performance. In a future publication we will continue detailing the use and function of these machines, as well as some safety considerations during their use.