induction generator. Presentation on the topic "device and principle of operation of the generator" Presentations on the structure of biological generators

Class: 11

Lesson Objectives:

• continue studying the topic of alternating current;
• explain the device and principle of operation of a three-electrode lamp, types and types of alternating current generators;
• continue the formation of natural science ideas on the topic under study;
• create conditions for the formation of cognitive interest, activity of students;
• promote the development of convergent thinking;
• formation of communicative communication.

Equipment: interactive complex SMART Board Notebook, on each table there is a “Collection of Physics” by G.N. Stepanova.

Lesson teaching method: Conversation using the interactive SMART Board Notebook.

Lesson plan:

1. Orgmoment
2. Checking knowledge, updating it (by the method of frontal survey)
3. Learning new material (the framework of the new material is the presentation)
4. Anchoring
5. Reflection

During the classes

tube generator

Above, the use of a three-electrode lamp in an electronic amplifier was considered. However, triodes are also widely used in tube generators, which are used to create alternating currents of various frequencies.

The simplest circuit of a tube generator is shown in fig. 192. Its main elements are a triode and an oscillatory circuit. To power the filament of the lamp, a Bn filament battery is used. The anode circuit includes an anode battery Ba and an oscillatory circuit consisting of an inductance coil Lk and a capacitor Ck. The coil Lc is included in the grid circuit and is inductively connected to the coil Lk of the oscillatory circuit. If you charge a capacitor and then close it to an inductor, then the capacitor will periodically discharge and charge, and damped electrical current and voltage oscillations will occur in the oscillatory circuit circuit. The damping of oscillations is caused by energy losses in the circuit. To obtain undamped oscillations of alternating current, it is necessary to periodically add energy to the oscillatory circuit with a certain frequency using a high-speed device. Such a device is a triode. If the cathode of the lamp is heated (see Fig. 192) and the anode circuit is closed, then an electric current will appear in the anode circuit, which will charge the capacitor Sk of the oscillatory circuit. The capacitor, discharging onto the inductor Lk, will cause damped oscillations in the circuit. The alternating current passing through the coil Lk induces an alternating voltage in the coil Lc, which acts on the lamp grid and controls the current strength in the anode circuit.

When a negative voltage is applied to the grid of the lamp, the anode current in it decreases. With a positive voltage on the grid of the lamp in the anode circuit, the current increases. If at this moment there is a negative charge on the upper plate of the capacitor Sk of the oscillatory circuit, then the anode current (electron flow) will charge the capacitor and thereby compensate for the energy loss in the circuit.

The process of decreasing and increasing current in the anode circuit of the lamp will be repeated during each period of electrical oscillations in the circuit.

If, with a positive voltage on the grid of the lamp, the upper plate of the capacitor Sk is charged with a positive charge, then the anode current (electron flow) does not increase the charge of the capacitor, but, on the contrary, reduces it. In this position, the oscillations in the circuit will not be maintained, but will be damped. To prevent this from happening, it is necessary to correctly turn on the ends of the coils Lk and Lc and ensure that the capacitor is charged in a timely manner. If oscillations do not occur in the generator, then it is necessary to swap the ends of one of the coils.

The tube generator is a converter of the DC energy of the anode battery into AC energy, the frequency of which depends on the inductance of the coil and the capacitance of the capacitor, forming an oscillatory circuit. It is easy to understand that this transformation in the generator circuit is performed by a triode. The emf, induced in the coil Lc by the current of the oscillatory circuit, periodically acts on the lamp grid and controls the anode current, which in turn recharges the capacitor at a certain frequency, thus compensating for energy losses in the circuit. This process is repeated many times during the entire operation of the generator.

The considered process of excitation of undamped oscillations in the circuit is called the self-excitation of the generator, since the oscillations in the generator support themselves.

Alternators

Electric current is generated in generators - devices that convert energy of one form or another into electrical energy. Generators include galvanic cells, electrostatic machines, thermobatteries, solar panels, etc. The scope of each of the listed types of electric power generators is determined by their characteristics. So, electrostatic machines create a high potential difference, but are unable to create any significant current in the circuit. Galvanic cells can give a large current, but the duration of their action is short. The predominant role in our time is played by electromechanical induction alternators. These generators convert mechanical energy into electrical energy. Their action is based on the phenomenon of electromagnetic induction. Such generators have a relatively simple device and make it possible to obtain large currents at a sufficiently high voltage.

At present, there are many types of induction generators. But they all consist of the same basic parts. This is, firstly, an electromagnet or a permanent magnet that creates a magnetic field, and, secondly, a winding in which a variable EMF is induced (in the considered model, this is a rotating frame). Since the EMF induced in series-connected turns add up, the amplitude of the induction EMF in the frame is proportional to the number of turns in it. It is also proportional to the amplitude of the alternating magnetic flux Ф = BS through each turn. To obtain a large magnetic flux in generators, a special magnetic system is used, consisting of two cores made of electrical steel. The windings that create a magnetic field are placed in the grooves of one of the cores, and the windings in which the EMF is induced are placed in the grooves of the other. One of the cores (usually internal), together with its winding, rotates around a horizontal or vertical axis. That is why it is called a rotor. The fixed core with its winding is called the stator. The gap between the stator and rotor cores is made as small as possible. This ensures the highest value of the flux of magnetic induction. In large industrial generators, an electromagnet, which is a rotor, rotates, while the windings in which the EMF is induced are laid in the slots of the stator and remain motionless. The fact is that current is supplied to the rotor or removed from the rotor winding to an external circuit with the help of sliding contacts. To do this, the rotor is equipped with slip rings attached to the ends of its winding. The fixed plates - brushes - are pressed against the rings and connect the rotor winding with the external circuit. The strength of the current in the windings of an electromagnet that creates a magnetic field is much less than the strength of the current given by the generator to the external circuit. Therefore, it is more convenient to remove the generated current from the fixed windings, and to supply a relatively weak current through the sliding contacts to the rotating electromagnet. This current is generated by a separate DC generator (exciter) located on the same shaft. In low-power generators, the magnetic field is created by a rotating permanent magnet. In this case, rings and brushes are not needed at all. The appearance of EMF in the fixed stator windings is explained by the appearance of a vortex electric field in them, generated by a change in the magnetic flux during the rotation of the rotor.

A modern electric current generator is an impressive structure of copper wires, insulating materials and steel structures. With dimensions of several meters, the most important parts of the generators are manufactured with millimeter precision. Nowhere in nature is there such a combination of moving parts that could generate electrical energy so continuously and economically.

The main characteristics of electrical materials lesson development presentation. Alternator transformer production transfer and use. Receiving and transmitting alternating electric current Transformer. Devices with permanent magnets for generating electricity. Getting electricity with an alternator. Report on the discipline of physics on the topic of the use of a transformer. Obtaining alternating current using an induction generator. Obtaining alternating current using induction generators. Alternators play a role in power generation. Scope of industrial alternators. Alternators and generating alternating current emf. Calculation of EMF in an alternating magnetic field.

Regional State Autonomous Vocational Educational Institution "Borisov Agromechanical College"

• Presentation for the lesson on the topic; The device and principle of operation of a car generator.

• according to MDK 01 02 "Device, maintenance
• and car repair

• Zdorovtsov Alexander Nikolaevich

The device and principle of operation of a car generator Generator

• - a device that converts the mechanical energy received from the engine into electrical energy. Together with the voltage regulator, it is called a generator set. Alternators are installed on modern cars.

Requirements for the generator:

• the output parameters of the generator must be such that in any modes of vehicle movement there is no progressive discharge of the battery;
• the voltage in the car's on-board network, fed by the generator, must be stable over a wide range of changes in speed and loads.

Pulley

• - serves to transfer mechanical energy from the engine to the generator shaft through a belt

generator housing

• consists of two covers: front (from the side of the pulley) and rear (from the side of the slip rings), designed to mount the stator, install the generator on the engine and place the bearings (supports) of the rotor. The back cover contains a rectifier, a brush assembly, a voltage regulator (if it is built-in) and external leads for connecting to an electrical equipment system;

Rotor -

• The rotor consists

• steel shaft with two beak-shaped steel bushings located on it. Between them there is an excitation winding, the conclusions of which are connected to slip rings. The generators are predominantly equipped with cylindrical copper slip rings;

• 1. rotor shaft; 2. rotor poles; 3. excitation winding; 4. slip rings.

stator

• generator stator

• - a package made of steel sheets, having the shape of a pipe. In its grooves there is a three-phase winding, in which the power of the generator is generated;

• 1. stator winding; 2. winding conclusions; 3. magnetic core

Assembly with rectifier diodes

• Assembly with rectifier diodes

• - combines six powerful diodes, pressed three into the positive and negative heat sinks;

• 1. power diodes; 2. additional diodes; 3. heat sink.

Voltage regulator

• - a device that maintains the voltage of the vehicle's on-board network within the specified limits when the electrical load, generator rotor speed and ambient temperature change;

brush knot

• – Removable plastic construction. It has spring-loaded brushes in contact with the rotor rings;

Generator device Types of generators installed on cars

• Non-contact generator with excitation from permanent magnets.
• Beak-shaped alternator with slip rings
• Inductor alternator.

• a - generator model;
• · b-rotor with permanent magnet NS and with six claw-shaped poles;
• · in - a six-pole stator with three phase windings connected by a "star";
• · NS - cylindrical permanent magnet with N and S poles;
• M - stator magnetic circuit;
• · R- magnetic circuit of the rotor in the form of claw-shaped tips made of solid steel;
• · Ф - magnetic flux of the rotor;
• 8- air gap;
• F. - phase winding of the stator;
• · EF - EMF induced in the phase winding;
• · w - circular frequency of rotation of the rotor;
• 1. 2, 3, total - conclusions of the phase windings connected by a "star".

Non-contact generator with permanent magnet excitation

• the spinning rotor is a permanent magnet and the phase windings are coils on a fixed stator. Such a generator is called a non-contact permanent magnet excited alternator. It can be single phase or multidimensional. The generator is simple in design, reliable, not afraid of dirt, does not require electrical excitation, does not have rubbing electrical contacts, the service life is determined by the drying of the insulation of the phase windings. But on modern passenger cars, a generator with excitation from permanent magnets is not used due to the impossibility of strictly maintaining a constant operating voltage in it when changing the speed of the internal combustion engine.

Beak-shaped alternator with slip rings

• a - generator model; b - a dissected rotor with an excitation coil W„ and with six north N and six south S beak-shaped poles of a permanent electromagnet; c - simplified design of the generator;
• 1 - magnetic circuit M of the stator with phase windings Wf
• 2 - beak-shaped pole pieces of the rotor;
• 3 - excitation winding Wв;
• 4 - fan impeller;
• 5 - drive pulley;
• 6 - magnetic circuit R of the rotor;
• 7 - body covers;
• 8 - built-in rectifier;
• 9 - contact rings K;
• 10 - brush holder KShM with brushes.

Beak-shaped alternator with slip rings

• The winding Wb is connected with its terminals to the slip rings K, which, in turn, are connected through the brushes of the KShM to the external electrical excitation circuit. In this way, the beak-shaped rotor becomes a multi-pole permanent electromagnet, the magnetomotive force of which can be easily adjusted by changing the excitation current, which is very important for automotive power generators.
• The beak-shaped rotor generator with slip rings has the widest application in modern passenger cars.

• a - generator model;
• b - connection diagram of the windings on a single-phase stator;
• c - simplified design of the generator;
• 1 - - groove of the rotor
• ;2 - bearing;
• 3 - rotor shaft;
• 4 - rotor pole
• ;5 - generator housing; Wv, Wf - excitation and phase windings.

Inductor alternator

• The main difference of this generator is that its rotating rotor is a passive magnetically soft ferromass, and the excitation winding is installed on a fixed stator together with phase windings. To reduce magnetic losses, the ferromass of the rotor, as well as the stator, is made of a set of thin plates of electrical steel. The generator is non-contact. The operation of such a generator is based on the periodic interruption of the constant magnetic flux, the stator, which, when the rotor rotates, is achieved by periodically changing the size of the air gap between the stator and the rotor. Thus, the inductor generator is synchronous and is controlled by voltage by changing the excitation current in the stator winding. In the inductor generator, the principle of obtaining EMF by changing the magnetic conductivity in the air gap is implemented: when controlling the magnitude of the induction of the stator magnetic field. By appropriate selection of the configuration of the surface of the passive rotor and stator pole pieces, it is possible to approximate the periodicity of the change in the magnetic flux to a sinusoidal law, which provides a sinusoidal shape to the operating voltage of the generator.

Used materials and Internet resources

• http://respektt.ru/foto/generator_ustroistvo.jpg
• http://www.mlab.org.ua/articles/electric/59-electric-generator.html
• http://www.domashniehitrosti.ru/generator4.html
• Rodichev V.A.: Trucks. M.: Publishing Center "Academy", 2010-239s.

The quantitative growth in the use of energy has led to a qualitative leap in its role in our country: a large branch of the national economy has been created - energy. The electric power industry occupies an important place in the national economy of our country. Nuclear power plant in France Hydroelectric cascade

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Task: The transformation ratio of the transformer is 5. The number of turns in the primary coil is 1000, and the voltage in the secondary coil is 20 V. Determine the number of turns in the secondary coil and the voltage in the primary coil. Determine the type of transformer?

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13

It will not come as a surprise to anyone that today the popularity, demand and demand for devices such as power plants and alternators are quite high. This is explained, first of all, by the fact that modern generator equipment is of great importance for our population. In addition, it must be added that alternating current generators have found their wide application in a wide variety of fields and areas. Industrial generators can be installed in places such as clinics and kindergartens, hospitals and catering establishments, freezers and many other places that require a continuous supply of electricity. Pay attention to the fact that the lack of electricity in the hospital can lead directly to the death of a person. That is why generators must be installed in such places. Also quite common is the phenomenon of using alternating current generators and power plants in construction sites. This allows builders to use the equipment they need even in areas where there is no electrification at all. However, this was not the end of the matter. Power plants and generator sets have been further improved. As a result of this, we were offered household alternating current generators, which could be quite successfully installed for the electrification of cottages and country houses. Thus, we can conclude that modern alternators have a fairly wide range of applications. In addition, they are able to solve a large number of important problems associated with the incorrect operation of the electrical network, or its absence.

"AC circuits" - Application of electrical resonance. Vector diagram of AC voltages. Ohm's law. Current fluctuations. Electrical circuits of alternating current. electrical resonance. Diagram. Three types of resistance. Vector diagram. Diagram when there is only inductive reactance in the AC circuit.

"Alternating current" - Alternating current. Alternator. Alternating current is an electric current that changes in time in magnitude and direction. Definition. EZ 25.1 Obtaining alternating current by rotating a coil in a magnetic field.

""Alternating current" physics" - Capacitor resistance. Capacitor in AC circuit. Current fluctuations on the capacitor. R,C,L in AC circuit. How does a capacitor behave in an AC circuit. How does inductance behave? Let's analyze the formula for inductive reactance. Using the frequency properties of a capacitor and an inductor.

"Resistance in an alternating current circuit" - Inductive resistance - a value that characterizes the resistance provided to alternating current by the inductance of the circuit. Capacitance - a value that characterizes the resistance provided to alternating current by electrical capacitance. Are the shapes the same color? Active resistance in an alternating current circuit.

"Alternating electric current" - Consider the processes occurring in a conductor included in an alternating current circuit. active resistance. Im= Um / R. i=Im cos ?t. Free electromagnetic oscillations in the circuit quickly decay and therefore are practically not used. Conversely, undamped forced oscillations are of great practical importance.

"Transformer" - If the answer is "yes", then what current source should the coil be connected to and why? Write a summary for paragraph 35 Physical processes in a transformer. Task2. AC source. EMF of induction. K is the transformation ratio. Write a formula. Can a step-up transformer be made into a step-down transformer?