I found an article on the Internet about how to convert a car generator to a permanent magnet generator. Is it possible to use this principle and remake the generator with your own hands from asynchronous electric motor? It is possible that there will be large energy losses due to the wrong arrangement of the coils.
I have an asynchronous type motor with a voltage of 110 volts, speed – 1450, 2.2 amperes, single-phase. I do not undertake to make a homemade generator using containers, as there will be large losses.
It is suggested to use simple engines according to this scheme.
If you change an engine or generator with round-shaped magnets from the speakers, do you need to install them in crabs? Crabs are two metal parts, are anchored outside the field coils.
If magnets are placed on a shaft, the shaft will bypass the magnetic power lines. How will there be excitement then? The coil is also located on a metal shaft.
If you change the connection of the windings and make a parallel connection, accelerate to a higher speed normal values, then it turns out 70 volts. Where can I get a mechanism for such speeds? If you rewind it to lower speeds and lower power, the power will drop too much.
An asynchronous motor with a closed rotor is made of iron, which is filled with aluminum. You can take a homemade generator from a car, which has a voltage of 14 volts and a current of 80 amperes. This is good data. An engine with a commutator running on alternating current from a vacuum cleaner or washing machine can be used for a generator. Set the bias to the stator, voltage direct current remove from brushes. According to the highest EMF, change the angle of the brushes. Coefficient useful action tends to zero. But nothing better than a synchronous generator has been invented.
I decided to test a homemade generator. A single-phase asynchronous motor from a small washing machine was turned with a drill. I connected a 4 µF capacitance to it, it turned out 5 volts 30 hertz and a current of 1.5 milliamps for a short circuit.
Not every electric motor can be used as a generator using this method. There are motors with a steel rotor that have a low degree of magnetization on the remainder.
Need to know the difference between conversion electrical energy and energy generation. There are several ways to convert 1 phase into 3. One of them is mechanical energy. If the power station is disconnected from the outlet, then all conversion is lost.
It is clear where the movement of the wire with increasing speed will come from. It is not clear where the magnetic field will come from to produce the EMF in the wire.
It's easy to explain. Due to the magnetism mechanism that remains, an emf is generated in the armature. A current arises in the stator winding, which is shorted to the capacitance.
The current has arisen, which means it gives an increase in the electromotive force on the coils of the rotor shaft. The resulting current increases the electromotive force. The stator electric current produces a much greater electromotive force. This goes until the stator equilibrium is established magnetic flux and rotor, as well as additional losses.
The size of the capacitors is calculated so that the voltage at the terminals reaches the nominal value. If it is small, then reduce the capacity, then increase it. There were doubts about old motors, which supposedly do not excite. After accelerating the rotor of a motor or generator, you need to quickly poke a small amount of volts into any phase. Everything will return to normal. Charge the capacitor to a voltage equal to half the capacity. Turn on using a three-pole switch. This applies to a 3-phase motor. This circuit is used for generators of passenger transport cars, since they have a squirrel-cage rotor.
Method 2
You can make a homemade generator in another way. The stator has a clever design (it has a special design solution), and it is possible to adjust the output voltage. I made this type of generator with my own hands at a construction site. The engine produced 7 kW at 900 rpm. I connected the excitation winding according to a 220 V delta circuit. I started it at 1600 rpm, the capacitors were 3 to 120 uF. They were switched on by a contactor with three poles. The generator acted as a three-phase rectifier. Powered from this rectifier electric drill with a 1000 watt collector, and a 2200 watt circular saw, 220 V, a 2000 watt grinder.
I had to make a soft start system, another resistor with a shorted phase after 3 seconds.
This is not correct for motors with commutators. If you double the rotating frequency, the capacitance will also decrease.
The frequency will also increase. The tank circuit was switched off automatically so as not to use the reactivity torus and not waste fuel.
During operation, you must press the contactor stator. Three phases dismantled them as unnecessary. The reason lies in the high gap and increased field dissipation of the poles.
Special mechanisms with a double cage for the squirrel and slanted eyes for the squirrel. Still, I got 100 volts and a frequency of 30 hertz from the washing machine motor, the 15 watt lamp does not want to light up. Very weak power. It is necessary to take a stronger motor, or install more capacitors.
A generator with a squirrel-cage rotor is used under the cars. Its mechanism comes from a gearbox and a belt drive. Rotation speed 300 rpm. It is located as an additional load generator.
Method 3
You can design a homemade generator, a gasoline-powered power plant.
Instead of a generator, use a 3-phase asynchronous motor of 1.5 kW at 900 rpm. The electric motor is Italian and can be connected with a triangle or a star. First, I placed the motor on a base with a DC motor and attached it to the coupling. I started turning the engine at 1100 rpm. A voltage of 250 volts appeared on the phases. I connected a 1000 watt light bulb, the voltage immediately dropped to 150 volts. This is probably due to phase imbalance. For each phase it is necessary to include separate load. Three 300-watt light bulbs will not be able to reduce the voltage to 200 volts, theoretically. You can put a larger capacitor.
The engine speed must be increased and not reduced when under load, then the power supply to the network will be constant.
Significant power is required; an autogenerator will not provide such power. If you rewind a large KAMAZ, then 220 V will not come out of it, since the magnetic circuit will be oversaturated. It was designed for 24 volts.
Today I was going to try connecting the load through a 3-phase power supply (rectifier). They turned off the lights in the garages, but it didn’t work. In the city of power engineers, the lights are systematically turned off, so it is necessary to create a source of constant power supply with electricity. There is an attachment for electric welding that is attached to the tractor. To connect an electric tool, you need a constant voltage source of 220 V. There was an idea to construct a homemade generator with your own hands, and an inverter for it, but, on batteries You can't work for long.
The electricity was recently turned on. I connected an asynchronous motor from Italy. I placed it with the chainsaw motor on the frame, twisted the shafts together, and installed a rubber coupling. I connected the coils according to a star circuit, the capacitors in a triangle, 15 μF each. When I started the motors, there was no power output. I connected a capacitor charged to the phases, and voltage appeared. The engine produced its power of 1.5 kW. At the same time, the supply voltage dropped to 240 volts; at idle it was 255 volts. The grinder operated normally at 950 watts.
I tried to increase the engine speed, but there was no excitement. After the capacitor contacts the phase, voltage appears immediately. I will try to install a different engine.
What system designs are produced abroad for power plants? On 1-phase ones, it is clear that the rotor owns the winding, there is no phase imbalance, because there is one phase. In 3-phase there is a system that allows power adjustment when motors with the highest load are connected to it. You can also connect an inverter for welding.
Over the weekend I wanted to make a homemade generator with my own hands using an asynchronous motor. A successful attempt to make a homemade generator turned out to be connecting an old engine with a cast iron housing of 1 kW and 950 rpm. The motor is excited normally, with one 40 µF capacitance. And I installed three containers and connected them with a star. This was enough to start an electric drill and grinder. I wanted it to produce voltage output on one phase. To do this, I connected three diodes, a half-bridge. The fluorescent lamps for lighting burned out, and the bags in the garage were set on fire. I will wind the transformer into three phases.
Write comments, additions to the article, maybe I missed something. Take a look at, I will be glad if you find something else useful on mine.
The desire to make your home completely autonomous is inherent in every owner country cottage and even a small dacha. But if there are no special problems with water and sewerage, then centralized Electricity of the net unpleasant moments often arise. Therefore, many are trying to acquire autonomous mini-power plants that could maintain operation household appliances in case of a network failure.
But such equipment is very expensive and not everyone can afford it. What to do in such a situation? You can buy one unit for several houses by pooling, but then it must have more power, and, therefore, high price. There are more cheap option– assemble an electric generator with your own hands, using improvised means. Can anyone make such a device? Let's try to find out by analyzing the information on the network.
What are generators and where are they used?
- This is equipment capable of producing electricity by burning fuel. They come in both single- and three-phase. Moreover, the latter are distinguished by their ability to work with various loads.
They are used as a backup and, in some cases, permanent source of power supply and are intended for operation:
Types and their application features
Technological equipment of this class is classified according to the following parameters:
- Area of use;
- Type of fuel burned;
- Number of phases;
- Power.
Let's start with the scope of application. Depending on this factor, generators are divided into household and professional, although a simple electric generator can be assembled with your own hands. The first ones are usually made in the form of a compact power unit and have a power from 0.7 to 25 kW. They are equipped with a motor internal combustion, running on gasoline or diesel fuel and equipped with an air cooling system. Such devices are used as backup energy sources for household appliances and power tools, as well as a self-powered electric generator assembled with your own hands.
They are lightweight and low level noise, therefore they are widely used in private households. The operation and maintenance of such units is not difficult and anyone can handle it, as well as assemble it electric generator with your own hands.
Let's watch the video, a little about generators, their types and advantages:
Professional equipment is designed to operate as a constant source of energy supply. Typically such generators are used in medical institutions And administrative buildings, as well as in the construction industry during emergency and other work. Units of this class have significant weight and do not differ quiet operation, which significantly complicates their transportation and choice of installation location. But at the same time, they have a higher service life and reliability when operating in extreme conditions. The advantages of such electric generators include economical fuel consumption.
The power of industrial power plants can exceed 100 kW, which allows them to be used as backup power sources for electrical equipment of large enterprises. The disadvantage of these units is difficult maintenance.
The next parameter used in classification is fuel type:
- Petrol;
- Diesel;
The former have a small power range, but at the same time they are distinguished by mobility and ease of use, just like those made by yourself. They are used as backup sources, as they have a short motor life and high cost received energy.
Diesel units have a wide power range and can be used for power supply public institutions and even small villages. However, they are not compact in size and quiet in operation, so they must be installed on a reinforced foundation in a separate room.
They are mainly used in industrial facilities. They are highly environmentally friendly and low-cost energy generated.
Vary power plants and by the number of phases per:
- One;
- Three.
The former are suitable for devices with single-phase power supply in the corresponding networks. The latter can serve as a source of energy for various devices and are installed in houses with three-phase network wiring.
Design and principle of operation
Principle of operation
A machine capable of converting mechanical energy into electrical energy is called a power plant. Its principle of operation is based on what is well known to everyone from the course school physics the phenomenon of electromagnetic induction.
It says that an emf is generated in a conductor moving in a magnetic field and crossing lines of force. Therefore, it can be considered as a source of electricity.
But since this method is not entirely convenient for practical application, then in the generators it was slightly changed using rotational movement conductor. In theoretical terms, power plants are a system of electromagnets and conductors. But structurally, they consist of internal combustion engines and generators.
DIY power plant diagram
Many, trying to save money, try to create as much as possible homemade equipment, for example, a generator. There is no need to explain to anyone that this device is necessary in every home, but the industrial model is expensive.
To get similar equipment in a cheaper version, you will have to assemble it yourself. Exist various schemes electric generators assembled with your own hands: from the simplest - windmills, to more complex ones - made on the basis of internal combustion engines. Let's look at some of them.
Windmill - a simple option
Vyatryak scheme
You can assemble such a unit from scrap materials. It can be used both on a hike and in the country and is a fuel-free electric generator assembled with your own hands. It will require:
- DC electric motor (it will play the role of a generator);
- Carriage unit and driven sprocket from an adult bicycle;
- Roller chain from a motorcycle;
- Duralumin 2 mm thick.
All this is not required high costs, and perhaps even find it for free in your garage. You can see how to make an electric generator yourself in the video below. Assembly also does not require special knowledge. A chain sprocket is installed on the electric motor shaft.
Let's watch the video, detailed instructions for assembly:
It can also be attached to a bicycle frame. The blades of the windmill are made slightly curved and up to 80 cm in length. Even with a slight wind, such a device is capable of producing from 4 to 6 amperes and a voltage of 14 V. Even an engine from an old scanner can be taken as a generator for a windmill. This is the simplest electric generator that you can assemble with your own hands.
Power plant based on an old generator from a walk-behind tractor
Before looking for a diagram homemade device Decide which option will be the most affordable for you. Perhaps you can find a generator from an old walk-behind tractor and, based on it, assemble a device that can provide power to electric lamps located in several rooms.
An asynchronous motor of the AIR series with a rotation speed of up to 1600 rpm and a power of up to 15 kW is suitable as a generator for such an installation. It is connected using pulleys and a drive belt to a motor removed from the walk-behind tractor. The diameter of the pulleys must be such that the rotation speed of the electric motor used as a generator is 15% higher than the rated value.
Let's watch the video in detail about these works:
The motor windings must be star-connected, with a capacitor connected in parallel to each pair. The result is a triangle. But to ensure the operation of the generator, it is necessary that all generators have the same capacity.
Nowadays, producing your own electricity is not so unusual thing. Electricity networks are intermittent, especially outside large cities. And to avoid problems with this, many resort to using electric generators. In order to purchase or make one, you need to find out about the best electric generators that you can make with your own hands.
What it is
An electric generator is a special device that is designed to convert and accumulate electricity. And it is usually extracted from unusual sources - from gasoline and gas to environmentally friendly ones, such as wind, sun and water. Such a generator can be expensive. Even the most low-power ones can cost from 15,000 rubles.
Therefore, in order to save several tens of thousands, many create them themselves. It’s good that there are now quite a lot of ideas on how to make an electric generator with your own hands.
Principle of operation
Electromagnetic induction underlies the operating principle of an electric generator.
An artificial magnetic field is created. A conductor passes through it, creating an impulse. The pulse meanwhile becomes a direct current.
The generator itself has an engine that is capable of generating electricity through burning fuel. a certain type. It can be diesel fuel, gasoline, gas.
At this time, the fuel entering the combustion area produces gas during combustion. And the gas makes the crankshaft rotate. This in turn gives impulse to the driven shaft. The latter provides output energy in certain quantities.
Electric generators basically have two mandatory mechanisms - a rotor and a stator. Their availability does not depend on fuel and power.
The rotor is needed to create that same electromagnetic field. It is based on magnets that are located at the same distance from the core.
The stator does not move. This allows the rotor to move while the stator adjusts the electromagnetic field. Achieved due to the steel blocks in its structure.
Asynchronous
The types of electric generator devices do not end with the division based on fuel use. Also, depending on the type of rotor rotation, generators can be:
- Synchronous - more complex in their design. Voltage fluctuations lead to malfunctions. This affects work and productivity.
- Asynchronous - with an easy operating principle and other technical characteristics.
Magnetic coils on the rotor of a synchronous generator make it difficult for the rotor to move. The rotor in an asynchronous generator is more like a flywheel.
Design features have a great influence on efficiency. Synchronous ones have a loss of up to 11%. For asynchronous, the loss reaches a maximum of 5%. Such indicators make asynchronous devices popular not only in everyday life, but also in production.
Asynchronous generators have other advantages:
- Frequent repairs are not necessary, because the simple housing reliably protects the engine from spent fuel and excess moisture.
- The output rectifier will protect electrical appliances powered by the generator.
- Resistant to voltage surges.
- All parts in the design are quite reliable and durable, so operation without repairs can last more than 15 years.
- Thanks to resistance to surges and the ability to power devices with ohmic loads, the number of different devices for connection is growing - from computers to welding machines and lamps.
- High efficiency.
What materials are needed
To assemble a small asynchronous generator, the following parts will be useful:
- Engine. The easiest way is to take it from broken electrical appliances, because making it yourself is difficult and time-consuming. Engines made from washing machines.
- Stator. You need to take it ready-made, with winding.
- Transformer or rectifier. Useful if the output electricity has different power.
- Electric wires.
- Insulating tape.
Of course, to make wind and solar power generators with your own hands, you will need more complex circuits and a larger number of materials, but if desired, both of them and instructions for them can be found.
Note! 
Assembly
The assembly process can be complicated for various reasons. For example, there is no specific skill for a job. There is no experience in creating such devices. There are no necessary parts and spare parts. However, if all this and a great desire are present, then you can try.
But before starting work, you must fulfill several conditions - obtain materials and instructions for making an electric generator. And read them. And also take care of safety precautions.
Before starting work, it makes sense to take care of assembly diagrams and drawings. This will greatly facilitate and speed up the process.
Gas and gasoline electric generators are most often assembled by hand. But both when assembling them, and when assembling others, you need to make preparations and some calculations. For example, it is important to know the power of the required generator.
To determine the rotation speed, the motor must be connected to the network. To determine, you will need a tachometer. The value obtained from the measurements must be added to the compensatory value of 10%. This value helps prevent the engine from overheating.
Note! 
Taking into account the power, you need to select capacitors.
It is important to remember about grounding, because we are dealing with electricity. And this is not only a matter of device wear and tear, but also a safety issue.
The assembly itself is simple - the capacitors are connected to the motor one by one according to the diagram (it can be found on the Internet). That's all you need to create a low power generator.
This option is the most convenient and easiest. However, it is worth paying attention to the following points:
- You need to monitor the engine temperature so that it does not overheat.
- Sometimes the generator will need to be allowed to cool to 40 degrees.
- Efficiency may decrease depending on operating time. This is fine.
- The user will need to independently monitor the condition of the generator and connect measuring instruments to it.
After assembling the mechanical part, you should take care of the electrical side. You should start after installing the pulleys connected by a belt.
- The windings on an electric motor are connected according to a star circuit.
- The capacitors connected to the winding must form a triangle.
- The voltage will be removed between the end of the winding and the midpoint. Then the result is a current with a voltage of 220 volts, and between the windings - 380 volts.
Note! 
Experts give a few more useful tips that will help when assembling the generator:
- The electric motor can become very hot. To prevent this from happening, you need to replace the capacitors with ones with a lower capacity.
- Homemade electric generators usually require capacitors with a voltage of 400 volts or more. For proper operation One is enough.
- The network requires a three-phase transformer if all phases of the motor are needed to power the house.
Most likely, even made as in beautiful photos, a homemade electric generator, will not be able to compete with purchased models.
However, if you perceive it as an additional, backup source of electricity, then it is quite possible to make and use it. Moreover, as practice shows, making a generator yourself is not so difficult. You just need to put in the effort and everything will work out.
DIY photo of electric generators
Constant and uninterrupted supply of electricity in the house is the key to a pleasant and comfortable pastime at any time of the year. To organize autonomous power supply suburban area, we will have to resort to mobile installations - electric generators, which last years especially popular due to large assortment a variety of powers.
Scope of application
Many people are interested in how to make an electric generator for summer cottage? We will talk about this below. In most cases we use an asynchronous generator alternating current, which will produce energy to operate electrical appliances. In an asynchronous generator, the rotation speed of the rotors is higher than in a synchronous generator and the efficiency will be higher.
However, power plants have found their application in a wider range, as an excellent means for energy production, namely:
- They are used in wind power plants.
- Used as welding units.
- They provide autonomous support for electricity in the house on a par with a miniature hydroelectric power station.
The unit is turned on using the incoming voltage. Often, to start the device, the device is connected to power, but this is not entirely logical and rational decision for a mini-station, which itself must generate electricity, and not consume it to start. Therefore, in recent years, generators with self-excitation or sequential switching of capacitors have been actively produced.
How does an electric generator work?
An asynchronous electricity generator produces a resource if the motor rotation speed is faster than a synchronous one. The most common generator operates at parameters starting from 1500 rpm.
It produces energy if the rotor runs faster than the synchronous speed at start. The difference between these indicators is called slip and is calculated as a percentage relative to the synchronous speed. However, the stator speed is even higher than the rotor speed. Due to this, a stream of charged particles is formed that change polarities.
Watch the video, how it works:
When excited, the connected generator device takes control of the synchronous speed, independently controlling the slip. The energy leaving the stator passes through the rotor, however, the active power has already moved to the stator coils.
The basic principle of operation of an electric generator is the conversion of mechanical energy into electrical energy. Strong torque is required to start the rotor to produce power. The most adequate option, according to electricians, is “perpetual idling,” which maintains one rotation speed while the generator is operating.
Why is an asynchronous generator used?
Unlike a synchronous generator, an asynchronous one has a huge number of advantages and disadvantages. The main factor in choosing the asynchronous option was the low clear factor. A high clear factor characterizes the quantitative presence of higher harmonics in the output voltage. They cause unnecessary heating of the motor and uneven rotation. Synchronous generators have a clear factor value of 5-15%; in asynchronous ones it does not exceed 2%. It follows from this that an asynchronous energy generator produces only useful energy.
A little about the asynchronous generator and its connection:
An equally significant advantage of this type of electric generator is the complete absence of rotating windings and electronic parts that are sensitive to damage and external factors. Hence, this type The devices are not subject to active wear and will last longer.
How to make a generator with your own hands
Device asynchronous alternating current generator
Acquisition asynchronous electric generator– quite an expensive pleasure for the average resident of our country. Therefore, many craftsmen resort to solving the issue of self-assembly apparatus. The principle of operation, as well as the design, is quite simple. If you have all the tools, assembly will not take more than 1-2 hours.
According to the above-defined principle of operation of the electric generator, all equipment should be configured so that the rotations are faster than the engine speed. To do this, you need to connect the engine to the network and start it. To calculate the number of revolutions per minute, use a tachometer or tachogenerator.
Having determined the value of the engine rotation speed, add 10% to it. If the rotation speed is 1500 rpm, then the generator should run at 1650 rpm.
Now you need to remake the asynchronous generator “for yourself”, using capacitors of the required capacities. Use the following label to determine the type and capacity:
We hope it is already clear how to assemble an electric generator with your own hands, but please note: the capacitor capacity should not be very high, otherwise the generator running on diesel fuel will get very hot.
Install capacitors according to calculations. Installation requires a fair amount of attention. Ensure good insulation and use special coverings if necessary.
At the engine base, the generator assembly process is completed. Now it can already be used as a necessary source of energy. Remember that in the case where the device has a squirrel-cage rotor and produces a fairly serious voltage that exceeds 220 volts, it is necessary to install a step-down transformer that stabilizes the voltage at the required level. Remember, in order for all appliances in the house to work, there must be strict control of a homemade 220-volt electric generator in terms of voltage.
Watch the video, stages of work:
For a generator that will operate at low power, in order to save money, you can use asynchronous motors with one phase from old or unnecessary household electrical appliances, such as washing machines, drainage pumps, lawn mowers, chainsaws, etc. Motors from such household appliances should be connected in parallel to the winding. Alternatively, phase shifting capacitors can be used. They rarely differ in required power, so it will need to be increased to the required levels.
Such generators perform very well when it is necessary to power light bulbs, modems and other small devices with a stable active voltage. With certain knowledge, you can connect an electric generator to an electric stove or heater.
The generator, ready for operation, should be installed so that it is not affected by precipitation and environment. Take care of an additional casing that will protect the installation from adverse conditions.
Almost every asynchronous generator, be it brushless, electric, gasoline or diesel generator, it is considered a device with sufficient high level danger. Handle such equipment very carefully and always keep it protected from external weather and mechanical influences or make a casing for it.
Let's watch the video, good advice specialist:
Any autonomous unit should be equipped with special measuring instruments, which will record and display performance data. To do this, you can use a tachometer, voltmeter and frequency meter.
- Equip the generator with an on/off button whenever possible. To start, you can use manual start.
- Some electric generators require grounding before use, carefully assess the area and select a location for installation.
- When converting mechanical energy into electricity, sometimes the efficiency can drop by up to 30%.
- If you are not confident in your abilities or are afraid of doing something wrong, we advise you to purchase a generator at the appropriate store. Sometimes risks can turn out extremely bad...
- Monitor the temperature asynchronous generator and its thermal regime.
Results
Despite its ease of implementation, homemade electric generators- this is a very painstaking work that requires complete concentration on the design and correct connection. Assembly is only advisable from a financial point of view if you already have a working and unnecessary engine. Otherwise, you will pay more than half of its cost for the main element of the installation, and the total costs may significantly exceed market value generator
It is difficult not to notice how the stability of electricity supplies to suburban facilities differs from the provision of urban buildings and enterprises with electricity. Admit that you, as the owner of a private home or cottage, have more than once encountered interruptions, associated inconveniences and damage to equipment.
The listed negative situations, along with the consequences, will no longer complicate the lives of lovers of natural spaces. Moreover, with minimal labor and financial costs. To do this you just need to do wind generator electricity, which we talk about in detail in the article.
We have described in detail the options for manufacturing a system that is useful in the household and eliminates energy dependence. According to our advice, an inexperienced person can build a wind generator with their own hands. House master. This practical device will help to significantly reduce your daily expenses.
Alternative energy sources are the dream of any summer resident or homeowner whose plot is located far from central networks. However, when we receive bills for electricity consumed in a city apartment and look at the increased tariffs, we realize that a wind generator created for domestic needs would not hurt us.
After reading this article, perhaps you will make your dream come true.
Wind generator – perfect solution to provide a suburban facility with electricity. Moreover, in some cases, installing it is the only possible solution.
In order not to waste money, effort and time, let's decide: are there any external circumstances that will create obstacles for us during the operation of the wind generator?
To provide electricity to a summer house or small cottage, it is enough, the power of which will not exceed 1 kW. Such devices in Russia are equated to household products. Their installation does not require certificates, permits or any additional approvals.