Converting an asynchronous motor into a low-speed generator. We make a generator from an asynchronous electric motor on our own at home

The desire to develop an autonomous source of electricity production made it possible to build a generator from a conventional asynchronous motor. The development is reliable and relatively simple.

Types and description of asynchronous motor

There are two types of motors:

1. Squirrel cage rotor. It includes a stator (non-moving element) and a rotor (rotating element), which moves due to the operation of bearings attached to two motor shields. The cores are made of steel, and they are also insulated from each other. An insulated wire is located along the grooves of the stator core, and a rod winding is installed along the grooves of the rotor core or molten aluminum is poured. Special jumper rings play the role of a closing element of the rotor winding. Independent developments transform the mechanical movements of the motor and create alternating voltage electricity. Their advantage is that they do not have an alkaline collector mechanism, which makes them more reliable and durable.
2. Slip rotor– an expensive device that requires specialized service. The composition is the same as that of the short circuit rotor. The only exception is that the rotor and stator windings of the core are made of insulated wire, and its ends are connected to rings attached to the shaft. Special brushes pass through them, which connect the wires with an adjusting or starting rheostat. Because of low level reliability, it is used only for those industries for which it is intended.

Application area

The device is used in various industries:

1. Like a conventional engine for wind powered power plants.
2. For your own independent supply of an apartment or house.
3. Like small hydroelectric power stations.
4. As an alternative inverter type of generator (welding).
5. For creating uninterrupted system AC power supply.

Advantages and disadvantages of the generator

The positive qualities of the development include:

1. Simple and quick assembly with the ability to avoid disassembling the electric motor and rewinding the winding.
2. The ability to rotate electric current using a wind or hydraulic turbine.
3. Use of the device in motor-generator systems to convert a single-phase network (220V) to a three-phase (380V).
4. The ability to use development in places where there is no electricity, using an internal combustion engine for promotion.

Minuses:

1. It is problematic to calculate the capacitance of the condensate that is attached to the windings.
2. It is difficult to reach the maximum power mark that self-development is capable of.

Principle of operation

The generator produces electrical energy provided that the number of rotor revolutions is slightly higher than the synchronous speed. The simplest type produces about 1800 rpm, taking into account that its synchronous speed level becomes 1500 rpm.

Its operating principle is based on the conversion of mechanical energy into electricity. You can force the rotor to rotate and produce electricity using a strong torque. IN ideal– constant idling, which is able to maintain the same speed.

All types of motors that do not operate under force direct current, are called asynchronous. In them, the magnetic field of the stator spins faster than the field of the rotor, accordingly directing it in the direction of its movement. To change the electric motor into a functioning generator, you will need to increase the speed of the rotor so that it does not follow the magnetic field of the stator, but begins to move in the other direction.

You can get a similar result by connecting the device to the mains, with a large capacitance or a whole group of capacitors. They charge and accumulate energy from magnetic fields. The capacitor phase has a charge that is opposite to the motor current source, which causes the rotor to slow down and the stator winding to generate current.

Generator circuit

The circuit is very simple and does not require any special knowledge and skills. If you start the development without connecting it to the network, rotation will begin and, after reaching a synchronous frequency, the stator winding will begin to generate electrical energy.

By attaching a special battery of several capacitors (C) to its terminals, you can obtain a leading capacitive current, which will create magnetization. The capacitance of the capacitors must be higher than the critical designation C 0, which depends on the dimensions and characteristics of the generator.

In this situation, a self-starting process occurs, and a system with symmetrical three-phase voltage. The current generated directly depends on the capacitance of the capacitors, as well as the characteristics of the machine.

Do it yourself

To convert an electric motor into a functional generator, you will need to use non-polar capacitor banks, so it is better not to use electrolytic capacitors.

In a three-phase motor, you can connect a capacitor according to the following diagrams:

• "Star"– makes it possible to generate generation at a lower number of revolutions, but with a lower output voltage;
• "Triangle"- comes into operation when large quantities rpm, accordingly produces more voltage.

You can create your own device from a single-phase motor, but provided that it is equipped with a short-circuit rotor. To start the development, you should use a phase-shifting capacitor. A single-phase commutator-type motor is not suitable for conversion.

Required Tools

Creating your own generator is not difficult, the main thing is to have all the necessary elements:

1. Asynchronous motor.
2. Tachogenerator (device for measuring current) or tachometer.
3. Capacity for capacitors.
4. Capacitor.
5. Tools.

Step by step guide

1. Since you will need to reconfigure the generator so that the rotation speed exceeds the engine speed, you must first connect the engine to the mains and start it. Then use a tachometer to determine the speed of its rotation.
2. Having found out the speed, you should add another 10% to the resulting designation. For example, technical indicator motor is 1000 rpm, then the generator should have about 1100 rpm (1000*0.1%=100, 1000+100=1100 rpm).
3. You should select a capacitance for the capacitors. To determine the sizes, use the table data.

Capacitor table

Important! If the capacity is large, the generator will begin to heat up.

Select appropriate capacitors that can provide the required rotation speed. Be careful when installing.

Important! All capacitors must be insulated with a special coating.

The device is ready and can be used as a source of electricity.

Important! A device with a squirrel-cage rotor creates a high voltage, so if 220V is required, you should additionally install a step-down transformer.

Magnetic generator

The magnetic generator has several differences. For example, it does not require the installation of capacitor banks. The magnetic field that will create electricity in the stator winding is created by neodymium magnets.

Features of creating a generator:

1. It is necessary to unscrew both engine covers.
2. The rotor will need to be removed.
3. The rotor must be sharpened by removing upper layer required thickness (magnet thickness + 2mm). Perform this procedure yourself without turning equipment extremely difficult, so you should contact a turning service.
4. Make a template for round magnets on a piece of paper, based on the parameters, the diameter is 10-20 mm, the thickness is about 10 mm, and the swearing force is about 5-9 kg per cm 2. The size should be selected depending on the dimensions of the rotor. Then attach the created template to the rotor and place the magnets with their poles and at an angle of 15-20 0 to the rotor axis. The approximate number of magnets in one strip is about 8 pieces.
5. You should have 4 groups of stripes, each with 5 stripes. Between the groups there should be a distance of 2 magnet diameters, and between the strips in the group - 0.5-1 magnet diameter. Thanks to given location the rotor will not stick to the stator.
6. Having installed all the magnets, you should fill the rotor with a special epoxy resin. Once dry, cover the cylindrical element with fiberglass and impregnate it with resin again. This fastening will prevent the magnets from flying out during movement. Make sure that the diameter of the rotor is the same as before the groove, so that during installation it does not rub against the stator winding.
7. After drying the rotor, it can be installed into place and screw both engine covers.
8. Conduct tests. To start the generator, you will need to turn the rotor using an electric drill, and at the output measure the resulting current with a tachometer.

To redo or not

To determine whether the operation of a self-made generator is effective, you should calculate how justified the efforts to convert the device are.

This is not to say that the device is very simple. Engine asynchronous motor is not inferior in complexity to a synchronous generator. The only difference is the absence of an electrical circuit to initiate operation, but it is replaced by a battery of capacitors, which does not simplify the device in any way.

The advantage of capacitors is that they do not require additional maintenance, and receive energy from magnetic field rotor or the electric current produced. From this we can say that the only advantage of this development is the absence of the need for maintenance.

Another positive quality– clear factor effect. It consists in the absence of higher harmonics in the generated current, that is, the lower its indicator, the less energy is spent on heating, magnetic field and other aspects. For a three-phase electric motor this figure is about 2%, while for synchronous machines it is at least 15%. Unfortunately, taking this indicator into account in everyday life, when different types of electrical appliances are connected to the network, is unrealistic.

Other indicators and properties of the development are negative. It is not capable of providing the rated power frequency of the voltage produced. Therefore, the devices are used together with rectifying machines, as well as for charging batteries.

The generator is sensitive to the slightest fluctuations in electricity. In industrial developments, a battery is used for excitation, and in homemade version part of the energy goes to the capacitor bank. When the load on the generator is higher than its nominal value, it does not have enough electricity to recharge and it stops. In some cases, capacitive batteries are used, which change their dynamic volume depending on the load.

1. The device is very dangerous, so it is not recommended to use a voltage of 380 V, unless absolutely necessary.
2. In accordance with precautions and safety precautions additional grounding must be installed.
3. Monitor the thermal conditions of development. It is not inherent to it to work at idle speed. To decrease thermal effect The capacitor should be selected well.
4. Correctly calculate the power of the electrical voltage produced. For example, when in a three-phase generator only one phase is functioning, it means that the power is 1/3 of the total, and if two phases are working, respectively, 2/3.
5. It is possible to indirectly control the frequency of intermittent current. When the device is idling, the output voltage begins to increase and exceeds industrial values ​​(220/380V) by 4-6%.
6. It's best to isolate development.
7. You should equip your homemade invention with a tachometer and voltmeter to record its work.
8. It is advisable to provide special buttons to turn the mechanism on and off.
9. The efficiency level will decrease by 30-50%, this phenomenon is inevitable.

If necessary, a three-phase asynchronous electric motor with a squirrel-cage rotor of the “squirrel cage” type can be used as an alternating current generator.

This solution is convenient due to the wide availability of asynchronous motors, as well as the absence of a commutator-brush assembly in such motors, which makes such a generator reliable and durable. If there convenient way cause its rotor to rotate, then to generate electricity it will be enough to connect three identical capacitors to the stator windings. Practice shows that such generators can operate for years without the need for maintenance.

Since there is residual magnetization on the rotor, when it rotates, an induced emf will arise in the stator windings, and since capacitors are connected to the windings, there will be a corresponding capacitive current that will magnetize the rotor. With further rotation of the rotor, self-excitation will occur, due to which a three-phase sinusoidal current will be established in the stator windings.

In generator mode, the rotor speed must correspond to the synchronous frequency of the engine, which is higher than its operating (asynchronous) frequency. For example: the AIR112MV8 motor has a stator winding with 4 pairs of magnetic poles, which means its rated synchronous frequency is 750 rpm, but when operating under load, the rotor of this motor rotates at a frequency of 730 rpm, since it is an asynchronous motor. This means that in generator mode you need to rotate its rotor at a frequency of 750 rpm. Accordingly, for motors with two pairs of magnetic poles, the rated synchronous frequency is 1500 rpm, and for motors with one pair of magnetic poles - 3000 rpm.

Capacitors are selected in accordance with the power of the asynchronous motor used and the nature of the load. The reactive power provided by capacitors in this operating mode, depending on their capacitance, can be calculated using the formula:

For example, there is an asynchronous motor designed for a rated power of 3 kW when operating from three-phase network with a voltage of 380 Volts and a frequency of 50 Hz. This means that the capacitors at full load must provide all this power. Since the current is three-phase, we are talking about the capacitance of each capacitor. Capacity can be found using the formula:

Therefore, for a given 3kW three-phase induction motor, the capacitance of each of the three capacitors at full resistive load will be:

Starting capacitors of the K78-17, K78-36 and similar series for voltages of 400 Volts and higher, preferably 600 Volts, or metal-paper capacitors of similar ratings are perfect for this purpose.

Speaking about the operating modes of a generator from an asynchronous motor, it is important to note that at idle the connected capacitors will create a reactive current, which will simply heat the stator windings, so it makes sense to make the capacitor units composite and connect the capacitors in accordance with the requirements of a specific load. The no-load current, with this solution, will be significantly reduced, which will relieve the system as a whole. Loads of a reactive nature, on the contrary, will require the connection of additional capacitors exceeding the design rating due to the characteristic reactive loads power factor.

It is possible to connect the stator windings both in a star, to obtain 380 Volts, and in a triangle, to obtain 220 Volts. If there is no need for three-phase current, you can use only one phase by connecting capacitors to only one of the stator windings.

You can also work with two windings. Meanwhile, it must be remembered that the power supplied by each of the windings to the load should not exceed a third of the total power of the generator. Depending on your needs, you can connect a three-phase rectifier, or use direct alternating current. For ease of control, it is useful to organize an indicator stand with measuring instruments - voltmeters, ammeters, and a frequency meter. Automatic circuit breakers are ideal for switching capacitors.

Particular attention should be paid to safety precautions, take into account critical current values, and calculate the cross-sections of all wires accordingly. Reliable insulation is also an important safety factor.

The energy of the electric current, entering the inside of an asynchronous motor, easily turns into motion energy at the exit from it. But what if a reverse transformation is required? In this case, you can build homemade generator from an asynchronous motor. It will only function in a different mode: by performing mechanical work electricity will begin to be generated. The perfect solution– transformation into a wind generator – a source of free energy.

It has been experimentally proven that a magnetic field is created by an alternating electric field. This is the basis of the operating principle of an asynchronous motor, the design of which includes:

• The body is what we see from the outside;
• Stator is the stationary part of the electric motor;
• A rotor is an element that is driven.

The main element of the stator is the winding, to which an alternating voltage is applied (the principle of operation is not on permanent magnets, but on a magnetic field that is damaged by alternating electric). The rotor is a cylinder with slots in which the winding is placed. But the current entering it has the opposite direction. As a result, two alternating electric fields are formed. Each of them creates a magnetic field, which begins to interact with each other. But the design of the stator is such that it cannot move. Therefore, the result of the interaction of two magnetic fields is the rotation of the rotor.

Design and principle of operation of the electric generator

Experiments also confirm that the magnetic field creates an alternating electric field. Below is a diagram that clearly illustrates the principle of operation of the generator.

If a metal frame is placed and rotated in a magnetic field, the magnetic flux penetrating it will begin to change. This will lead to the formation of an induced current inside the frame. If you connect the ends to a current consumer, for example, to an electric lamp, you can observe its glow. This suggests that the mechanical energy expended in rotating the frame within the magnetic field was converted into electrical energy, which helped light the lamp.

Structurally, an electric generator consists of the same parts as an electric motor: a housing, a stator and a rotor. The difference lies only in the principle of operation. The rotor is driven by the magnetic field created by the electric field in the stator winding. And it appears electricity in the stator winding due to a change in the magnetic flux penetrating it, due to the forced rotation of the rotor.

From electric motor to electric generator

Human life today is unthinkable without electricity. Therefore, power plants are being built everywhere, converting the energy of water, wind and atomic nuclei into electrical energy. It has become universal because it can be converted into the energy of movement, heat and light. This became the reason for the massive spread of electric motors. Electric generators are less popular because the state supplies electricity centrally. But still, sometimes it happens that there is no electricity and there is nowhere to get it from. In this case, a generator from an asynchronous motor will help you.

We have already said above that the electric generator and the engine are structurally similar to each other. This raises the question: is it possible to use this miracle of technology as a source of both mechanical and electrical energy? It turns out that it is possible. And we will tell you how to convert a motor into a current source with your own hands.

The meaning of the rework

If you need an electric generator, why make it from an engine if you can buy new equipment? However, high-quality electrical equipment is not a cheap pleasure. And if you have one that is not used in this moment motor, why shouldn't it serve him well? By simple manipulations and with minimal costs you will get an excellent current source that can power devices with active loads. These include computer, electronic and radio equipment, ordinary lamps, heaters and welding converters.

But savings are not the only advantage. Advantages of an electric current generator constructed from asynchronous electric motor:

• The design is simpler than that of a synchronous analogue;
• Maximum protection of the insides from moisture and dust;
• High resistance to overloads and short circuits;
• Almost complete absence of nonlinear distortions;
• Clearance factor (a value expressing the uneven rotation of the rotor) no more than 2%;
• The windings are static during operation, so they do not wear out for a long time, increasing their service life;
• The generated electricity immediately has a voltage of 220V or 380V, depending on which engine you decide to convert: single-phase or three-phase. This means that current consumers can be directly connected to the generator, without inverters.

Even if the electric generator cannot fully meet your needs, it can be used in conjunction with a centralized power supply. In this case, we are again talking about saving: you will have to pay less. The benefit will be expressed as the difference obtained by subtracting the electricity generated from the amount of electricity consumed.

What is needed for remodeling?

To make a generator from an asynchronous motor with your own hands, you must first understand what is preventing the conversion of electrical energy from mechanical energy. Let us recall that for the formation of an induction current, the presence of a magnetic field that changes with time is necessary. When the equipment operates in motor mode, it is created in both the stator and the rotor due to power from the network. If you switch the equipment to generator mode, it turns out that there is no magnetic field at all. Where does he come from?

After the equipment operates in motor mode, the rotor retains residual magnetization. It is this force that causes an induced current in the stator due to forced rotation. And in order for the magnetic field to be maintained, it will be necessary to install capacitors that carry capacitive current. It is he who will maintain magnetization due to self-excitation.

We have sorted out the question of where the original magnetic field came from. But how to set the rotor in motion? Of course, if you spin it with your own hands, you can power a small light bulb. But the result is unlikely to satisfy you. The ideal solution is to turn the motor into a wind generator, or windmill.

This is the name given to a device that converts the kinetic energy of the wind into mechanical, and then into electrical. Wind generators are equipped with blades that move when they meet the wind. They can rotate in both vertical and horizontal planes.

From theory to practice

Let's build a wind generator from a motor with our own hands. For easy understanding, diagrams and videos are included with the instructions. You will need:

• Device for transmitting wind energy to the rotor;
• Capacitors for each stator winding.

It is difficult to formulate a rule according to which you could choose a wind catching device the first time. Here you need to be guided by the fact that when the equipment is operating in generator mode, the rotor speed should be 10% higher than when operating as an engine. You need to take into account not the nominal frequency, but the idle speed. Example: the rated frequency is 1000 rpm, and in idle mode it is 1400. Then to generate current you will need a frequency of approximately 1540 rpm.

The selection of capacitors by capacity is made according to the formula:

C is the required capacity. Q – rotor rotation speed in revolutions per minute. P is the number “pi” equal to 3.14. f – phase frequency (constant value for Russia, equal to 50 Hertz). U – network voltage (220 if one phase, and 380 if three).

Calculation example : Three-phase rotor rotates at 2500 rpm. ThenC = 2500/(2*3.14*50*380*380)=56 µF.

Attention! Do not select more capacity calculated value. Otherwise, the active resistance will be high, which will lead to overheating of the generator. This can also happen when the device is started without load. In this case, it will be useful to reduce the capacitance of the capacitor. To make it easy to do it yourself, place the container not as a whole, but as a prefabricated one. For example, 60 μF can be made up of 6 pieces of 10 μF connected in parallel to each other.

How to connect?

Let's look at how to make a generator from an asynchronous motor, using the example of a three-phase motor:

1. Connect the shaft to a device that rotates the rotor using wind energy;
2. Connect the capacitors in a triangle pattern, the vertices of which are connected to the ends of the star or the vertices of the stator triangle (depending on the type of winding connection);
3. If a voltage of 220 Volts is required at the output, connect the stator windings in a triangle (the end of the first winding with the beginning of the second, the end of the second with the beginning of the third, the end of the third with the beginning of the first);
4. If you need to power devices from 380 Volts, then a star circuit is suitable for connecting the stator windings. To do this, connect the beginning of all windings together, and connect the ends to the appropriate containers.

Step-by-step instructions on how to make a single-phase wind generator with your own hands low power:

1. Get it out of the old one washing machine electric motor;
2. Determine the working winding and connect a capacitor in parallel with it;
3. Ensure that the rotor rotates using wind energy.

You will get a windmill, like in the video, and it will produce 220 Volts.

For electrical appliances powered by DC, an additional rectifier will be required. And if you are interested in monitoring the power supply parameters, install an ammeter and a voltmeter at the output.

Advice! Due to the lack of constant wind, wind generators may sometimes stop working or not work at full capacity. Therefore, it is convenient to organize your own power plant. To do this, the windmill is connected to the battery during windy weather. The accumulated electricity can be used during calm periods.

An electric motor is a device that acts as an energy converter and operates in the mode of obtaining mechanical energy from electrical energy. Through simple transformations without the use of a permanent magnet, but thanks to residual magnetization, the motor begins to work as a power source. These are two mutually inverse phenomena that help you save: you don’t need to buy a wind generator if you have an electric motor lying around. Watch the video and learn.

(AG) is the most common AC electrical machine, used primarily as a motor.
Only low-voltage AGs (up to 500 V supply voltage) with a power from 0.12 to 400 kW consume more than 40% of all electricity generated in the world, and their annual output amounts to hundreds of millions, covering the most diverse needs of industrial and agricultural production, marine, aviation and transport systems, automation systems, military and special equipment.

These engines are relatively simple in design, very reliable in operation, have fairly high energy performance and low cost. That is why the scope of use of asynchronous motors is continuously expanding, both in new areas of technology and as a replacement for more complex electrical machines of various designs.

For example, there is significant interest in last years causes use of asynchronous motors in generator mode to provide power to both three-phase current consumers and DC consumers through rectifier devices. In systems automatic control, in servo electric drives, in computing devices, asynchronous tachogenerators with a squirrel-cage rotor are widely used to convert angular velocity into an electrical signal.

Application of asynchronous generator mode

Under certain operating conditions of autonomous power sources, the use of asynchronous generator mode turns out to be preferable or even the only possible solution, as, for example, in high-speed mobile power plants with a gearless gas turbine drive with a rotation speed n = (9...15)10 3 rpm. The work describes an AG with a massive ferromagnetic rotor with a power of 1500 kW at n = 12000 rpm, intended for the autonomous welding complex “Sever”. In this case, a massive rotor with longitudinal grooves of rectangular cross-section does not contain windings and is made of a solid steel forging, which makes it possible to directly couple the engine rotor in generator mode with a gas turbine drive at a peripheral speed on the rotor surface of up to 400 m/s. For a rotor with a laminated core and short circuit. With a squirrel cage winding, the permissible peripheral speed does not exceed 200 - 220 m/s.

Another example effective application Asynchronous motors in generator mode have been used for a long time in mini-hydroelectric power plants under stable load conditions.

They are characterized by ease of operation and maintenance, are easily switched on for parallel operation, and the shape of the output voltage curve is closer to sinusoidal than that of SGs when operating on the same load. In addition, the mass of AG with a power of 5-100 kW is approximately 1.3 - 1.5 times less than the mass of AG of the same power and they carry a smaller volume of winding materials. At the same time, in terms of design, they are no different from conventional motors and their mass production is possible at electrical machine-building plants that produce asynchronous machines.

Disadvantages of the asynchronous mode of the generator, asynchronous motor (IM)

One of the disadvantages of IM is that they consume significant reactive power (50% or more of the total power) necessary to create a magnetic field in the machine, which must come from parallel work asynchronous motor in generator mode with a network or from another source of reactive power (capacitor bank (BC) or synchronous compensator (SC)) during autonomous operation of the AG. In the latter case, it is most effective to include a capacitor bank in the stator circuit parallel to the load, although in principle it is possible to include it in the rotor circuit. For improvement operational properties In the asynchronous mode of the generator, capacitors can additionally be connected to the stator circuit in series or in parallel with the load.

In all cases battery life asynchronous motor in generator mode reactive power sources(BC or SK) must provide reactive power to both the AG and the load, which, as a rule, has a reactive (inductive) component (cosφ n< 1, соsφ н > 0).

The mass and dimensions of a capacitor bank or synchronous compensator can exceed the mass of an asynchronous generator, and only when сφ n = 1 (purely active load) are the dimensions of the SC and the mass of the BC comparable to the size and mass of the AG.

Another, most difficult problem is the problem of stabilizing the voltage and frequency of an autonomously operating AG, which has a “soft” external characteristic.

Using asynchronous generator mode As part of an autonomous system, this problem is further complicated by the instability of the rotor speed. Possible and currently used methods of voltage regulation in asynchronous generator mode.

When designing AG for optimization, calculations should be carried out to maximize efficiency in a wide range of rotation speed and load, as well as to minimize costs, taking into account the entire control and regulation scheme. The design of generators must take into account the climatic conditions of the wind turbine operation, constantly operating mechanical forces on structural elements and especially - powerful electrodynamic and thermal effects during transient processes that occur during startups, power interruptions, loss of synchronism, short circuits and others, as well as during significant gusts of wind.

Design of an asynchronous machine, asynchronous generator

The design of an asynchronous machine with a squirrel-cage rotor is shown using the example of an AM series engine (Fig. 5.1).

The main parts of the IM are a stationary stator 10 and a rotor rotating inside it, separated from the stator air gap. To reduce eddy currents, the rotor and stator cores are made from separate sheets stamped from electrical steel with a thickness of 0.35 or 0.5 mm. The sheets are oxidized (subjected to heat treatment), which increases their surface resistance.
The stator core is built into the frame 12, which is outer part cars. On the inner surface of the core there are grooves in which winding 14 is laid. The stator winding is most often made three-phase two-layer from individual coils with a shortened pitch from insulated copper wire. The beginnings and ends of the winding phases are brought out to the terminal box terminals and are designated as follows:

beginning - СС2, С 3;

ends - C 4, C5, Sat.

The stator winding can be connected in a star (Y) or triangle (D). This makes it possible to use the same motor at two different linear voltages, which are in relation to, for example, 127/220 V or 220/380 V. In this case, connection Y corresponds to switching on the IM to the highest voltage.

The assembled rotor core is pressed onto shaft 15 by a hot fit and is protected from rotation using a key. On the outer surface, the rotor core has grooves for laying winding 13. The rotor winding in the most common IMs is a series of copper or aluminum rods located in grooves and closed at the ends with rings. In engines with a power of up to 100 kW or more, the rotor winding is performed by filling the grooves with molten aluminum under pressure. Simultaneously with the winding, the closing rings are cast along with the ventilation wings 9. The shape of such a winding resembles a “squirrel cage”.

Motor with wound rotor. Asynchronous mode generator A.

For special asynchronous motors, the rotor winding can be designed similar to the stator winding. A rotor with such a winding, in addition to the indicated parts, has three slip rings mounted on the shaft, designed to connect the winding to the external circuit. In this case, the IM is called a motor with a wound rotor or with slip rings.

The rotor shaft 15 combines all the elements of the rotor and serves to connect the asynchronous motor to the actuator.

The air gap between the rotor and stator ranges from 0.4 - 0.6 mm for low-power machines and up to 1.5 mm for high-power machines. Bearing shields 4 and 16 of the engine serve as supports for the rotor bearings. Cooling of the asynchronous motor is carried out according to the principle of self-blowing by fan 5. Bearings 2 and 3 are closed from the outside with covers 1 having labyrinth seals. A box 21 with terminals 20 of the stator winding is installed on the stator housing. A plate 17 is attached to the body, on which the basic blood pressure data are indicated. In Fig. 5.1 it is also indicated: 6 - shield mounting socket; 7 - casing; 8 — body; 18 — paw; 19 - ventilation duct.

It was decided to convert an asynchronous motor as a generator for a windmill. This modification is very simple and affordable, so homemade structures In wind turbines you can often see generators made from asynchronous motors.

The modification consists of cutting the rotor under the magnets, then the magnets are usually glued to the rotor according to a template and filled with epoxy resin so that they do not fly off. They also usually rewind the stator with a thicker wire to reduce too much voltage and increase the current. But I didn’t want to rewind this motor and it was decided to leave everything as is, just convert the rotor to magnets. A three-phase asynchronous motor with a power of 1.32 kW was found as a donor. Below is a photo of this electric motor.

> The electric motor rotor was machined to lathe to the thickness of the magnets. This rotor does not use a metal sleeve, which is usually machined and placed on the rotor under the magnets. The sleeve is needed to enhance magnetic induction, through it the magnets close their fields by feeding each other from underneath and the magnetic field does not dissipate, but goes all the way to the stator. This design uses enough strong magnets 7.6*6mm in size in the amount of 160 pieces, which will provide good EMF even without a sleeve.

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> First, before gluing the magnets, the rotor was marked into four poles, and the magnets were placed at a bevel. The motor was four-pole and since the stator did not rewound, there should also be four magnetic poles on the rotor. Each magnetic pole alternates, one pole is conventionally “north”, the second pole is “south”. The magnetic poles are made at intervals, so the magnets are grouped closer together at the poles. After being placed on the rotor, the magnets were wrapped with tape for fixation and filled with epoxy resin.

After assembly, the rotor felt sticking, and when the shaft rotated, sticking was felt. It was decided to remake the rotor. The magnets were knocked together with epoxy and placed again, but now they are more or less evenly placed throughout the rotor, below is a photo of the rotor with magnets before being filled with epoxy. After filling, the sticking decreased somewhat and it was noticed that the voltage dropped slightly when the generator rotated at the same speed and the current increased slightly.

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After assembling the finished generator, it was decided to twist it with a drill and connect something to it as a load. A 220 volt 60 watt light bulb was connected, at 800-1000 rpm it burned at full intensity. Also, to test what the generator was capable of, a 1 kW lamp was connected; it burned at full intensity and the drill was not strong enough to turn the generator.

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At idle, at maximum drill speed of 2800 rpm, the generator voltage was more than 400 volts. At approximately 800 rpm the voltage is 160 volts. We also tried connecting a 500-watt boiler, after a minute of twisting the water in the glass became hot. These are the tests that the generator, which was made from an asynchronous motor, passed.

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Afterwards, a stand with a rotating axis was welded for the generator to mount the generator and tail. The design is made according to a scheme where the wind head is moved away from the wind by folding the tail, so the generator is offset from the center of the axis, and the pin behind is the pin on which the tail is placed.

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Here is a photo of the finished wind generator. The wind generator was installed on a nine-meter mast. When the wind was strong, the generator produced an idle voltage of up to 80 volts. They tried connecting a two-kilowatt tenn to it, but after a while the tenn became warm, which means the wind generator still has some power.

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Then a controller for the wind generator was assembled and the battery was connected through it for charging. The charging current was quite good, the battery quickly began to make noise, as if it were being charged from a charger.

So far, unfortunately, there are no detailed data on the power of the wind generator, as the user posted his wind generator here