Introduction of generator types
Today let's talk about generators
The main function of generators is to convert other forms of energy (such as water power, wind power…… etc.) into electrical equipment, which are widely used in industrial processes, agricultural production, national defense technology and daily life.
Also because of the wide range of uses of generators, it is subdivided into many types
Regarding generators, Longzhong has also used diesel generators to do related engineering performance cases:Generator electrostatic capacitance leakage detection alarm project
Without further ado, let us Longzhong introduce some common types of generators for you！
According to the "type of working power supply", it can be divided into: DC generator and AC generator
A DC generator is a rotating electrical machine that uses rotation to generate direct current. Although DC power must be used in some occasions, such as electroplating, electrolysis, and battery charging, railway electrification also uses DC power. However, power plants do not use DC generators, but use AC generators to generate AC power, which is then transformed and rectified. Supply DC load for DC current.
In fact, the development of DC generators came earlier than that of AC motors, but at present, the utilization rate is far less common than AC motors.
The two ends of the AC generator coil are respectively connected to two annular collector rings, and each ring is in contact with a brush at a fixed position. When the surface of the coil is perpendicular to the direction of the magnetic field, the most magnetic lines of force pass through the coil; when the surface of the coil is parallel to the direction of the magnetic field, the number of magnetic lines of force passing through the coil is the least (it can be regarded as zero). When the coil rotates in the magnetic field, the current in the coil changes direction once every half-turn (180 degrees). When the collector ring rotates with the coil, the positive and negative electrodes of the brushes change with time. The alternating direction of the output current is called alternating current.
In principle, the alternator can be divided into: synchronous generator, asynchronous generator, single-phase generator, three-phase generator
Synchronous generators are the most common among alternators and work according to the principle of electromagnetic induction. They convert mechanical energy into electrical energy through the relative motion of the rotor magnetic field and the stator windings. This type of generator is excited by DC current, which can provide both active power and reactive power, and can be used to supply power to various load devices that require AC power. Depending on the fuel and the prime mover used, it can be subdivided into many different types of generators.
In principle, an asynchronous generator is the same as a synchronous motor, which uses the rotating rotor magnetic field to induce power generation in the stator. The difference is that the magnetic field of the rotor is established in different ways. Synchronous motors are more intuitive, and the excitation power creates a magnetic field in the rotor through the excitation winding. In the asynchronous motor, the stator winding acts as the excitation winding of the rotor and also acts as the generator winding.
Single-phase generator (Single-Phase generator) When a single-phase sinusoidal current passes through the stator winding, the motor will generate an alternating magnetic field. The magnetic field strength and direction change sinusoidally with time, but the spatial direction is fixed. So it is also called alternating pulsating magnetic field. The alternating pulsating magnetic field can be decomposed into two rotating magnetic fields with the same rotation speed and opposite directions. When the rotor is stationary, the two rotating magnetic fields generate two torques in the rotor that are equal in magnitude and opposite in direction, so that the combined torque is zero and the motor cannot rotate.
Three-phase generator (Three-Phase generator) generates electromagnetic force through the current-carrying rotor conductor under the action of the stator rotating magnetic field, thereby forming electromagnetic torque on the motor shaft and driving the motor to rotate. In order to ensure the stable operation of the generator, the generator needs at least three windings.
The general public is very unfamiliar with three-phase AC power, the main reason is that three-phase AC power is more directly used by factories in industrial areas.
Synchronous generators are classified according to the prime mover: steam turbine generators, hydraulic generators, and wind turbines. They can be divided into diesel generators and gasoline generators by "fuel".
A hydro-generator is a generator that converts water energy into electrical energy with a hydro-turbine as the prime mover. When the water flows through the turbine, the water energy is converted into mechanical energy, and the rotating shaft of the turbine drives the rotor of the generator to convert the mechanical energy into electrical energy for output.
The rotational speed of the hydro-generator is low, about 100 to 1000 revolutions per minute (ie 100rpm & sim; 1000 rpm). In order to generate enough frequency power, it has a large number of poles. From Table 18-2 in Chapter 18 You can compare the rotation speed that various pole number generators should have. The output voltage of the hydro-generator is between 3 kV and 16.5 kV.
Turbo Generator, also known as thermal power plant burning coal or oil to generate heat, nuclear power plant splits nuclear fuel to generate energy, evaporates water into water vapor, drives the steam turbine to rotate, and then uses the steam turbine to drive the generator to rotate. The generator of the method is the turbine generator. The speed of the turbine generator is fast, about 1500 rpm to 3600 rpm, in order to generate a frequency of 50 Hz or 60 Hz, the number of poles is either 4 or 2, and its output voltage is between 11 kV and 36 kV, Higher voltage than hydro-generators.
Turbine-generator refers to a generator driven by a steam turbine. The superheated steam generated by the boiler enters the steam turbine and expands to do work, which makes the blades rotate to drive the generator to generate electricity.
It is usually used as an emergency power supply generator in factories, hospitals, buildings and public places, and is used as the main power source in temporary places, remote areas on outlying islands and ships.
Diesel generators (Diesel generators) are small power generation equipment that uses diesel fuel as fuel and rotates the crankshaft of the diesel engine to drive the generator to rotate and generate electricity. The whole set is generally composed of diesel engine, generator, control box, fuel tank, battery for starting and control, protection device, emergency cabinet and other components. It is usually used for daily power generation and emergency power generation in various households, offices, large, medium and small enterprises.
Gasoline Generator uses gasoline as fuel, and the energy generated by the combustion of steam turbine fuel or nuclear fission is converted into mechanical energy and transmitted to the generator, which is then converted into electrical energy by the generator. The interior is composed of stators, rotors, end covers and bearings. The kinetic energy is generated by burning the fuel in the cylinder to drive the reciprocating motion of the piston in the engine cylinder, thereby driving the connecting rod connected to the piston and the crank connected to the connecting rod to reciprocate circular motion around the center of the crankshaft to output power.
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