Electromagnetic principle-generator

The AC generators can also be divided into single-phase generators and three-phase generators.

Generator Principle
<1> generator Overview

A generator is a mechanical device that converts other forms of energy into electrical energy. It is driven by a turbine, a steam turbine, a diesel engine, or other power machinery, and uses water flow and air flow, the energy produced by fuel combustion or nuclear fission is converted into mechanical energy and transferred to the generator, and then from the generator to the electric energy. Generators are widely used in industrial and agricultural production, national defense, science and technology, and daily life.

There are many generator forms, but their working principles are based on the law of electromagnetic induction and the law of electromagnetic force. Therefore, the general principle of its construction is: Use appropriate magnetic conductivity and conductive materials to form a magnetic circuit and circuit for mutual electromagnetic induction, in order to generate electromagnetic power, to achieve the purpose of energy conversion.

The quality licensing system for exported generators has been implemented, and products that have not obtained an export quality license are not allowed to be exported.

<2> the classification of generators is summarized as follows:

Generator: DC Generator and AC Generator
Generators: Synchronous Generators and asynchronous generators (rarely used)
The AC generators can also be divided into single-phase generators and three-phase generators.

<3> generator structure and working principle

The generator is usually composed of stator, rotor, End Cover and bearing components.
The stator is composed of the stator core, wire package winding, seat, and other structural parts fixed.
The rotor is composed of the rotor core (or magnetic pole, magnetic pole) winding, protection ring, center ring, Sliding Ring, Fan and shaft.
The stator and rotor of the generator are connected and assembled by the bearing and end cover so that the rotor can rotate in the stator to cut the magnetic line and generate the induction potential, when connected to the loop, the current is generated.

Working principle of diesel generators
The diesel engine drives the generator and converts the diesel energy into electric energy.
In the cylinder of the diesel engine, the clean air filtered by the air filter is fully mixed with the high-pressure atomizing diesel fuel sprayed by the nozzle. Under the piston's uplink extrusion, the volume decreases and the temperature increases rapidly, reach the diesel fuel point. Diesel fuel is ignited, mixed gas burning, rapid expansion of the volume, push the piston downstream, known as the "work '. Each cylinder works in sequence, and the thrust acting on the piston goes through the connecting rod to become the force that pushes the crankshaft rotation, thus driving the crankshaft rotation.
When the brushless synchronous AC generator is installed in a coaxial manner with the crankshaft of the diesel engine, the rotation of the diesel engine can be used to drive the rotor of the generator. Based on the principle of "electromagnetic induction", the generator will output the induction potential force, closed load loop can generate current.
Here we only describe the most basic working principle of the generator set. To achieve usable and stable power output, a series of Diesel Engine and generator control and protection devices and circuits are also required. For details, please go to >>>

Gasoline generator principle
The gasoline engine drives the generator and converts the gasoline energy into electric energy.
In the gasoline engine cylinder, mixed gas combustion, rapid expansion of the volume, to promote the downstream piston. Each cylinder works in sequence, and the thrust acting on the piston goes through the connecting rod to become the force that pushes the crankshaft rotation, thus driving the crankshaft rotation. If the brushless synchronous AC generator is installed in a coaxial manner with the crankshaft of the gasoline engine, the rotor of the generator can be driven by the rotation of the gasoline engine. By using the 'electromagnetic induction 'principle, the generator will output the induction potential force, closed load loop can generate current. For details, please go to >>>

Working principle of Synchronous Generators
· Main magnetic field establishment: the excitation winding is connected to DC excitation current to establish polar excitation magnetic field, that is, the main magnetic field is established.
· Streaming conductor: A three-phase symmetric Armature Winding acts as a power winding and acts as a carrier for inductive potential or current.
· Cutting motion: the original motor is dragged to the rotor for rotation (input mechanical energy to the motor ), polar excitation magnetic field rotates along the axis and sequentially cut the stator phase winding (equivalent to the winding conductor reverse cutting excitation magnetic field ).
· Generation of Alternating Potential: due to the relative Cutting Motion Between the armature winding and the main magnetic field, the armature winding will sense the size and direction of the three-phase symmetric alternating potential with periodic changes. AC power supply can be provided through the guide line. For details, please go to >>>

Principles of asynchronous generators

Working principle of DC generators
The working principle of the DC Generator is to convert the Alternating Voltage force generated by the induction in the armature coil by the commutator with the reversing function of the brush to convert it from the brush end to the DC voltage.
Without the DC voltage on the brush, use the original motor to drag the armature to make it rotate at constant speed in the clockwise direction. The magnetic lines under different polarity magnetic poles are cut on both sides of the coil, and the induction generates an EMR in it, the direction of the potential force is determined by the right hand. This electromagnetic condition is shown in the figure. Due to the continuous rotation of the armature, the magnetic line at the edge of the coil AB and Cd in the magnetic field must be cut alternately by the magnetic line at the N pole and S pole, although each side of the coil and the entire coil are alternating in the direction of the induction potential. the induction EMF in the coil is an alternating EMR, while in the brush a, the EMF at the B end is a DC EMR (to be exact, it is a constant pulse-induced EMR in the direction ). Because, no matter where the armature is transferred during the rotation process, the commutator works with the brush to change the direction, electric Brush a always has positive polarity due to the potential force in the coil side of the cut N Pole Magnetic line. In the same way, brush B always has a negative pole, so the brush end can lead to the same direction but the size change of the Pulse vibration potential. If the number of coils increases at each pole, the pulse vibration degree can be reduced to obtain the DC potential. This is how the DC generator works. It also shows that the sub-DC Generator is essentially an AC generator with a commutator.
From the perspective of the basic electromagnetic situation, a DC motor can operate either as a motor or as a generator in principle, but the constraints are different. Add the DC voltage on the two brush ends of the DC motor to input the armature of the electric energy and output the mechanical energy from the motor shaft. Drag the production machinery to convert the electric energy into mechanical energy and turn it into a motor, if the source motor is used to drag the armature of the DC motor, and the brush does not add a dc voltage, the brush end can lead to the dc emr as the DC power supply and output power, the motor converts mechanical energy into electrical energy and becomes a generator. The principle that one motor can run as a motor or generator is called reversible principle in the motor theory. For details, please go to >>>

Working principle of the AC Generator
Click to view the Principle Demonstration of the AC Generator

Steam Turbine Generator Principle
The steam engine uses high-temperature and high-pressure steam expansion to work. Through the connecting rod and crank, the reciprocating movement of the piston is converted into the rotation of the main shaft to drive the generator to generate electricity.
A steam turbine is used to push the rotation of a turbine. The basic principle of its operation is similar to that of a common windmill, A steam turbine is a main structure composed of a very thick steel plate and a steel plate with many dense strip leaves along the outer side. When the high-pressure overheated steam from the boiler is sprayed from the nozzle to the blade, the turbine rotates, the greater the steam speed, the faster the turbine rotates (that is, the kinetic energy of steam can be converted into the kinetic energy of steam in the injection, and its kinetic energy is converted into the mechanical energy of the machine shaft rotation ). For details, please go to >>>

Principle of hydro-generator
The Installation Structure of the hydro-generator is usually determined by the type of the turbine. There are mainly the following types:
1) The horizontal structure of the hydro-generator is usually driven by an impact turbine.
2) vertical structures are widely used in domestic hydro-generators. A vertical hydro-generator set is usually driven by a Mixed-flow or axial-flow turbine. The vertical structure can be divided into two types: suspension and umbrella. The thrust bearing of the generator is in the upper part of the rotor collectively referred to as suspension type, located in the lower part of the rotor collectively referred to as umbrella type.
3) the tubular turbine is driven by a tubular turbine. A tubular turbine is a special type of Axial-Flow Turbine with fixed or adjustable Runner Blades. It is mainly characterized by horizontal or inclined layout of the runner axis, which is consistent with the direction of the water flow of the turbine inlet pipe and outlet pipe. Tubular Turbine Generators have the advantages of compact structure and light weight. They are widely used in power stations with low water heads. For details, please go to >>>

Principle of hand-cranked generators

Principles of wind generators

Principle and Application of new water-cooled generators
Water-cooled generators use water instead of fans for cooling. The stator is the main heating part of the AC generator, and the stator and coil winding are the key cooling part of the water-cooled AC generator. The Front End Cover and Rear End Cover of the generator are made of aluminum, and a water channel trough is opened. The stator and coil winding are fixed and sealed by synthetic resin, and the aluminum enclosure and water channel are isolated between the stator and the rotor. The water channels are connected to the inlet and outlet pipes, and the inlet and outlet pipes are connected to the engine cooling water system respectively.

In this way, when the engine is running, the cooling water flow cyclically under the engine water pump. Through the generator housing, the stator coil winding and stator core can be effectively cooled, at the same time, it also cools the rotor, inner-Tibet type regulator, bearings and other hot parts.

Compared with air-cooled generators, water-cooled generators have complicated internal structures, higher leak-proof sealing requirements, and higher costs. At the same time, due to the connection pipe problem, the installation and layout are also subject to many restrictions, reducing the degree of freedom. However, the power generation and low noise performance of water-cooled generators are incomparable to those of wind and cooling generators.

First, water-cooled generators have good low-speed charging characteristics. We know that there is an inflection point on the current characteristic curve of the AC generator, that is, the current is generated only after the so-called "0 ampere speed", and the current can be charged only when it rises to a certain extent. At which speed or above, the "inflection point" occurs and the rechargeable current is related to the excitation current size.

Because water-cooled generators greatly reduce the temperature rise of stator, rotor, and regulator, excitation current can be increased accordingly. The larger the excitation current, the higher the output voltage, therefore, when the water-cooled AC generator rotates at low speed, it also has a good charging performance. This low speed charging performance is very important for the normal use of urban vehicles.

Second, water-cooled generators have low noise. The fan is omitted, so there is no noise from the generator fan. It is introduced that the noise of water-cooled generators is 15 decibels lower than that of air-cooled generators at 3500 rpm.

The advantages of water-cooled generators are favored and considered as the development direction of Automotive generators. Some people think that in a 12 volt car, less than 2500 Watts is suitable for use in air-cooled AC generators, more than 2500 watts or 42 Volts is suitable for use in water-cooled AC generators