Scheme and description of contact capacitor welding for batteries. How is capacitor welding done by hand? What capacitors are in spot welding machines

Widely used in industry, can be called capacitor welding. The rules for its implementation are regulated by GOST.

Its principle is based on the discharge of an electric charge accumulated on a block of capacitors onto the connected products. At the point of contact of the electrodes, a discharge occurs and a short electric arc is formed, sufficient to melt the metal.

Capacitor welding is most widely used in instrumentation. It is capable of welding metals up to 1.5 mm, and the thickness of the second part can be much larger. In the welding of thin products in terms of economy, productivity and quality, capacitor welding has no competitors.

It is transformer and transformerless. In the first variant, large energy can be stored on capacitors by using high voltage and discharging through a step-down transformer with high currents. The second option is characterized by simplicity and a minimum of details.

Depending on the characteristics of the formation of the seam, capacitor welding is divided into:

• point;
• suture;
• butt.

The first, point method, is mainly used in instrument making and the production of electronic equipment. It is actively used for welding thin parts with thick ones.

It is also called roller, used for welding membranes and electrovacuum devices. A continuous, tight seam is obtained due to the fact that point connections are made with overlap. The role of the electrodes is performed by rotating rollers.

Carried out by reflow or resistance. In the first method, a discharge first occurs between the parts to be welded, the place of the future connection is melted under the action of the formed arc, and then they are deposited, after which the metals are joined. In the second case, the discharge and subsequent welding occurs at the moment of contact between the parts.

Advantages

The advantage of capacitor welding is that due to the high energy density and the short duration of the welding pulse, the heat-affected zone is very small, stresses and deformations are minimal. The equipment is simple and efficient.

Due to the fact that at the moment of discharge, the capacitor unit is disconnected from the network, it does not affect its parameters in any way. The only drawback is that it is used only when working with thin metals.

Another advantage of capacitive welding is its compactness. Capacitor welding does not need powerful power sources, the device can be charged between transferring the electrode to the next point.

There are practically no harmful gases during the welding process. The device is very economical, all stored energy is used to melt metals at the junction point. Due to the fact that the charge on the capacitors is constant, a high-quality and stable arc is obtained.

Capacitor welding allows you to weld non-ferrous metals of small thickness. In addition, it can connect dissimilar metals and alloys due to the high concentration of energy in a small area.

Due to the fact that the capacitor welding system operates in a discrete mode (first charge, then discharge), it has enough air cooling, which simplifies the construction of the welding unit.

The capacitive welding machine is used for joining all kinds of steels, parts made of brass, aluminum, bronze. It can weld dissimilar metals, thin to thick sheets.

The ability to adjust the discharge energy and pulse duration allows micro-welding, for example, in a watch mechanism. The condenser apparatus can weld refractory tungsten filaments, used in jewelry.

Technological features

Depending on the technological process, capacitor-type welding can be:

• contact;
• shock;
• point.

During resistance welding, the energy accumulated in the tank is discharged into metal parts that were previously tightly connected to each other. An electric arc occurs at the place where the electrodes are pressed, at which the current reaches 10-15 thousand amperes with an arc duration of up to 3 ms.

In the case of shock capacitor welding, the discharge occurs at the moment of a brief impact of the electrode on the workpiece. The duration of the arc exposure is 1.5 ms. This reduces the thermal impact on the surrounding area and improves the quality of the weld.

In capacitor spot welding, an arc appears between the electrodes and the workpieces between them. The discharge process lasts from 10 to 100 ms (depending on settings), and the metal bonding takes place in a small area.

Transformerless device

Having decided to make a device for capacitor welding on their own, they first choose a design option. The simplest option is a transformerless circuit. It can be implemented with high or low voltage capacitors.

In the first case, you will need a step-up transformer and 1000 V capacitors with a capacity of 1000 microfarads. In addition, you will need a high-voltage diode bridge for rectifying alternating current, a switch, electrodes with connecting wires.

Welding takes place in two stages. At the first stage, the capacity is charged, at the second, after switching its leads to the welding electrodes and touching them to the welding site, a discharge occurs, and the parts are connected. The flowing current reaches 100 A, the pulse duration is 5 ms. This option is dangerous for humans due to the high operating voltage.

The second option requires a step-down transformer, a capacitor bank for voltages up to 60 V with a capacity of 40,000 microfarads or more, a diode bridge, and a switch.

The welding process is identical to the first case, only currents of 1-2 kA and a duration of up to 600 ms pass through the welding point. The power of the transformer does not really matter, it can be 100-500 watts.

DIY transformer circuit

When using a transformer circuit, you will need a step-up transformer and a 1 kV diode bridge for charging, 1000 uF capacitors and a step-down transformer, through the secondary winding of which the accumulated charge is discharged at the junction of the workpieces.

With this design of the spot welding machine, the discharge duration is 1 ms, and the current reaches 6000 A. After charging the capacitor bank with a switch, they are connected to the primary winding of the step-down transformer. In the secondary winding, an EMF is induced, which causes huge currents with closed electrodes on the workpieces to be connected.

The quality of welding will greatly depend on the condition of the electrode block. The simplest option is clamps for fixing and pressing contactors.

But the design is more reliable, where the lower electrode is fixed, and the upper one can be pressed against the lower one with the help of a lever. It is a copper bar with a diameter of 8 mm and a length of 10-20 mm fixed to any base.

The upper part of the rod is rounded to obtain reliable contact with the metal to be welded. A similar copper rod is mounted on a lever, when lowered, the electrodes must be tightly connected. The base with the lower electrode is isolated from the upper arm. The secondary winding is connected to the electrodes with a 20 mm 2 wire.

The primary winding is wound with PEV-2 0.8 mm, the number of turns is 300. The secondary winding of ten turns is wound with 20 mm2 wire. A core Ш 40 with a thickness of 70 mm can be used as a magnetic circuit. To control the charge / discharge, a PTL-50 or KU202 thyristor is used.

Part preparation

Before starting capacitor welding, it is necessary to prepare the parts to be joined. Rust, scale and other contaminants are cleaned from them.

The blanks are aligned properly and then placed between the lower fixed electrode and the upper movable one. Then they are strongly compressed by electrodes. By pressing the start button, an electric discharge is applied.

Metal is welded at the point of contact between the electrodes. It is necessary to open the electrodes after some time, which is necessary for cooling and crystallization of the place of welding under pressure.

After that, the part moves, during this time the device has time to charge, and the welding process is repeated. The size of the welding spot should be 2-3 times the smallest thickness of the workpieces to be joined.

When it is necessary to weld a sheet up to 0.5 mm thick to other parts, regardless of their thickness, a simplified welding method can be used. One electrode is attached to the thick part to be welded in any convenient place using a clamp.

In the place where you need to weld a thin part, it is pressed manually with a second electrode. You can use car clips. Then welding takes place. As you can see, the process is not too complicated, and affordable for home conditions.

Capacitor welding is a technology for creating a seamless connection of metal products. Connections are made by short-term impulses of electrical energy.

The molten metal and filler material are mixed, after solidification, a welding seam is formed. In the process of performing work, the welder is exposed to intense exposure to ultraviolet radiation, which has a negative effect on the human body.

Unlike this method, capacitor welding is not harmful to health Therefore, a minimum set of personal protective equipment is not required to perform the work. Due to the accuracy of the devices, after connecting the elements, there are practically no traces left on the surface. Rational use of energy saves electricity.

Modern science does not have the ability to create massive devices, therefore, at present, capacitor spot welding is used to connect compact elements.

The principle of the point method

The connection process is as follows:

1. Two blanks are connected by two conductors to create a closed circuit.
2. Capacitors accumulate the required amount of energy from the mains.
3. A short-term charge is applied to the conductors, under the influence of which the contact area melts, forming connections.

The method allows you to connect products that differ in the type of metal. However, the thickness of one of the elements should not exceed 0.15 cm.

The work does not require the use of any consumables. The melt zone consists exclusively of the billet alloy.

Requirements

To obtain a quality result, the following requirements must be met:

1. The duration of the working cycle does not exceed 3 ms.
2. Capacitors receive an operating level of energy in a short period of time.
3. As a preliminary preparation, the surface is cleaned from contaminants and degreased.
4. Copper rods are best suited for the role. Their thickness is three times greater than the thinnest part of the workpiece.
5. At the moment of contact, the elements to be connected must be tightly pressed against each other. After the discharge, a short period of time is needed for the compound to crystallize, therefore the electrodes are disconnected with a slight delay.

Varieties

There are several technological methods for performing capacitor contact welding. Let's consider them in more detail.

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The method is designed to connect products with different dimensions, such as thin wire and metal sheet. The connection is made by a short current pulse stored in the capacitors. Widely used in the electrical industry.

Roller

In this case, the seam consists of many point joints overlapping each other.. They provide complete sealing. Welding is performed with special electrodes that continuously rotate around their axis. The main area of ​​use is the production of devices for converting electromagnetic energy.

Butt

It got its name due to the ability to weld wires of small cross-section butt-to-butt. It is carried out by the method of reflow or resistance. In the first case, before contact, the ends of the parts are melted under the action of an electric arc. Then they start welding. In the second case, all actions are performed at the moment of contact between the workpieces.

Advantages and disadvantages

The advantages of the devices include:

• work productivity;
• can be used for industrial and domestic purposes;
• low power consumption;
• simple design;
• long period of operation;
• point impact allows you to make connections without thermal deformation of the product;
• does not require the use of consumables;
• small dimensions allow you to freely move the device yourself.

Capacitors in other welding technologies also play an important role. For example, aluminum electrolytic capacitors in inverters and semi-automatic devices are responsible for increasing the voltage level, and also smooth out possible ripples.

There are only two disadvantages:

1. Low power does not allow to connect workpieces of large cross section.
2. Operation of the machine causes interference that may interfere with the operation of the network.

With your own hands: a diagram of a simple device

In addition to industrial work, spot welding is often used in everyday life.. The factory-made device is quite expensive. On the Internet, you can find many drawings for self-assembly of various activities. For example, do-it-yourself capacitor welding for a battery is made from a dipole coil and a transformer with contact triodes.

Consider a diagram and description of capacitor welding with your own hands, in which a transformer is used to transmit pulses.

The device diagram looks like this:

For assembly you will need:

1. Capacitor with a capacity of 1000 microfarads. To store charge.
2. Ferrite core with W-shaped plates for the manufacture of a transformer.
3. Copper wire with a cross section of 0.8 mm. For the primary winding, 3 turns will be enough.
4. Copper bus. It will be used to make the secondary winding, which should have 10 turns.
5. Thyristor type KU-202M. For voltage switching control.

Such a device will easily cope with elements up to 0.5 mm thick.

Scheme and description of a more powerful device

The scheme of the device for spot welding on capacitors, capable of working with products of greater thickness, is as follows:

The basis of the device is 6 capacitors for 10,000 microfarads, connected into a single battery. In this case, two 70TPS12 thyristors connected in parallel were used as keys. The capacitors are charged using a boost converter. The resistance of the resistor is 130 ohms.

For visual control over the level of charge, there is a block of light indicator with 3 divisions.

The estimated current strength is 2000 A, and the voltage value is 32 V.

The only drawback of this model is the duration of charging the capacitors, which is 45 seconds.

The assembled apparatus will not be able to weld a large-diameter stud, but it will completely cope with a wire with a cross section of up to 5 mm.

Please note that industrial designs are made in compliance with GOSTs that regulate this industry. In the case of independent inventions, all responsibility for possible consequences lies with the designer.

Contact block device

The mechanism for fixing and moving the electrodes along the working plane is called a contact block.. The primitive design implies manual adjustment of the contacts. In advanced models, a block of hardware is responsible for the reliability of fastening.

In this case, the lower rod is fixed in a fixed position. Its length should be in the range of 10-20 mm, and the cross section should be at least 8 mm.

The second rod is attached to the movable platform. To adjust the pressure, install the simplest screws.

To ensure safety, it should be ensured that there is reliable insulation between the site and the base of the power unit.

Work procedure

The workflow can be roughly divided into three stages:

1. Training. The working surface must be thoroughly cleaned from corrosion and oil stains.
2. Working cycle. Products are joined in the desired position. After that, electrodes are brought to them. The charge is supplied after pressing the start button.
3. Repositioning a Part. If necessary, the product is moved for a new point impact.

The use of ready-made devices

Capacitor welders have found many applications:

1. Automotive. Body elements are connected only by spot welding.
2. aircraft industry. This industry is distinguished by special requirements for the accuracy of work.
3. Instrumentation. For connecting miniature elements that should not be subject to deformation.
4. Construction. With the help of this technology, the connection of thin-sheet metals is performed.
5. homework. Devices help in the repair of household appliances.

Conclusion

The capacitor welding machine is an excellent device that can connect products with different structures. Its main advantages are simplicity and reliability with small dimensions. If necessary, you can make a simple apparatus for domestic needs.

Electrical engineer of the 1st category Kalyazin Artem Vitalievich, work experience - 15 years: « At home, I am engaged in self-repair of all household appliances, with rare exceptions. Just a week ago, a dead lithium-ion battery from a phone fell into my hands. With the help of materials at hand, I decided to make a small welding machine with capacitors. It took exactly 6 hours from drawing up the scheme to completion of the work. I was pleased with the performance - wires with a cross section of 3 mm will be connected easily. Thyristors and capacitors were at hand, but if I had to buy everything in a store, the costs would not exceed 500-600 rubles».

Contact welding is used to create strong metal joints of alloys, dissimilar and homogeneous materials at the level of interatomic bonds. During this process, an electric current heats the metal until plastic deformation occurs, and the connection itself occurs due to the additional pressing of the parts to each other. One of the options for spot welding is capacitor welding. The main difference of this process from others is the way of energy accumulation for metal melting. Capacitor welding is carried out using the energy previously stored on capacitors.

The main parts of the equipment will be one or more capacitors that accumulate charge due to the input from a constant voltage source. When a certain level of charge is reached, the electrodes from the capacitors are connected to the welding points. Electric current provides fast and strong heating of the surface, leading to the melting of the metal and the formation of a turned weld. Typically, each discharge of the capacitor lasts only 1-3 milliseconds, due to this, heating outside the zone itself practically does not occur.

Capacitor Welding Application

Modern automatic production is capable of creating up to 600 discharges of the battery and connection points per minute with strict adherence to the quality characteristics of welding and the repeatability of all manipulations. At the same time, the operation of the equipment does not require consumables in the form of electrodes (as for inverter welding) or welding wire (as for argon arc welding). In addition, no coolant is needed to carry out the work.

With the help of capacitor welding in radio electronics, it is possible to connect parts that are afraid of overheating and cannot be bonded with conventional fluxes. This type of welding can be used for microscopic elements.

Capacitor welding is especially in demand in car body repair. The discharge does not deform the walls of the parts and does not burn through them, so there is no need for straightening.

On a note. This type of welding is used to repair and create jewelry, in the manufacture of watches, cinema, and photographic equipment.

Capacitor welding has certain disadvantages, the main of which is the impulse load. This load occurs in the network during the rapid discharge of capacitors. Such pulses create interference and can lead to the failure of all equipment.

Types of welding

The discharge from the capacitors can be immediately sent to the place of welding or it can be done through the secondary winding of the capacitor. In the first case, welding will be called transformerless, and in the second, transformer welding. The first option is used for joining, and the last option is used when creating seams and in spot work.

In shock-capacitor welding, the parts are connected during the impact of the capacitor through current-collecting contacts, and in some cases these contacts may be the parts themselves.

Let's consider how this process occurs when welding studs, which will simultaneously play the role of current-collecting contacts. First, it is necessary to ensure that the end of the hardware touches the surface with which it is to be connected. Then, through the hardware, a capacitor discharge is supplied to the welding area. As a result, a micro-arc is formed and the temperature rises significantly. The contact point of the pin and the surface of the part is melted. With the help of pressure, the hardware is immersed in the molten layer. Then the alloy cools and at the same time strengthens, and the hardware is welded.

In transformer welding, the capacitor after charging is connected to a step-down transformer through the primary winding. A potential appears on the secondary winding, which is less than the incoming pulse. Next comes the discharge, the capacitor starts charging again, and the energy goes through the primary winding of the transformer. Then the whole process is repeated. This technology allows you to make accurate welds by conducting several cycles of operations up to 5 discharges per second.

For household appliances, transformer welding is usually used, because transformerless equipment is more bulky. Only one bank of capacitors should have a capacity of about 100,000 microfarads. You can use an ionistor for these purposes - this is a supercapacitor, comparable in size to a conventional electrolytic one, but with a much larger capacity. However, the use of an ionistor leads to a significant increase in the cost of equipment. Therefore, the option with transformer welding is more preferable.

In modern equipment, the power and frequency of capacitor discharges is regulated through PIC controllers. All manipulations are controlled through a computer, and most processes are automated. To work on such equipment, you must not only read the description in full, but also take training courses.

Homemade capacitor welding

There are different options for creating homemade welding machines. Simple do-it-yourself spot welding can be done using a spotter, a device used in car body repair. In appearance, this equipment is a power unit, to which electrodes or a welding gun are attached using a flexible hose.

In order to assemble such a welding machine, you will need:

1. Transformer 5-20 W for 220 V with an input voltage of 5V - 1 piece;
2. Transformer not less than 1000 W - 1 piece;
3. Rectifier diodes with direct current up to 300 mA - 4 pieces;
4. Electrodes (if available, you can take a welding gun);
5. Thyristor KU 202 or T142-80-16 (in the diagram, an outdated version of PTL-50) - 1 piece;
6. Electrolytic capacitor 1000.0 x25 V - 1 piece;
7. Copper wire with a cross section of 35mm2 - at least 1 meter.

Fuses and switches are also needed, and if desired, a housing.

Note! A microwave oven transformer can be used in this circuit, but this device must be modified by removing the magnetic shunts and the secondary winding. Next, in place of the secondary winding, make several turns of copper wire. Then, by changing the number of turns, you need to adjust the operation of the device.

How does capacitor welding happen with your own hands? In the design of the spotter, 2 main nodes can be distinguished:

1. relay with thyristor V9;
2. welding transformer T2.

The winding is connected through a V5-V8 diode bridge, into which an electronic relay is connected diagonally. During operation in the "On" position at the switch S1, the voltage from the power source goes to the primary winding of the transformer T1. This charges the capacitor. At the same time, the winding of the transformer T2 is de-energized, and the thyristor V9 is closed. When you press the S3 button, the charge from the capacitor through the variable resistor R1 goes to the control electrode of the thyristor V9. The current breaks off the thyristor, the voltage goes through the primary winding of the transformer T2, a powerful pulse occurs in the secondary winding with a duration of about 0.1 seconds. At the end of the discharge of the capacitor C1, the system returns to its original state.

Attention! During discharge, the current is 350-500 A. Use a homemade spotter with extreme caution.

This device can be used for small welding work, it will not work to connect fittings or pipes with it.

Video

Aluminum electrolytic capacitors are one of the main elements that ensure the stability of the high-frequency inverter welding machines. Reliable high-quality capacitors for this type of application are produced by companies,.

The first devices using the arc welding method used adjustable AC transformers. Transformer welding machines are the most popular and are used to this day. They are reliable, easy to maintain, but have a number of disadvantages: high weight, high content of non-ferrous metals in the transformer windings, low degree of automation of the welding process. It is possible to overcome these shortcomings by switching to higher current frequencies and reducing the size of the output transformer. The idea to reduce the size of the transformer by switching from the mains frequency of 50 Hz to a higher frequency was born back in the 40s of the XX century. Then it was done with the help of electromagnetic transducers-vibrators. In 1950, for these purposes began to use vacuum tubes - thyratrons. However, it was undesirable to use them in welding technology due to low efficiency and low reliability. The widespread introduction of semiconductor devices in the early 60s led to the active development of welding inverters, first on a thyristor basis, and then on a transistor one. Insulated gate bipolar transistors (IGBTs) developed at the beginning of the 21st century gave a new impetus to the development of inverter devices. They can operate at ultrasonic frequencies, which can significantly reduce the size of the transformer and the weight of the apparatus as a whole.

Simplified block diagram of the inverter can be represented from three blocks (Figure 1). At the input there is a transformerless rectifier with a capacitance connected in parallel, which makes it possible to raise the DC voltage to 300 V. The inverter unit converts direct current into high-frequency alternating current. The conversion frequency reaches tens of kilohertz. The unit includes a high-frequency pulse transformer, in which the voltage is reduced. This block can be manufactured in two versions - using single-cycle or double-cycle pulses. In both cases, the transistor block operates in a key mode with the ability to adjust the turn-on time, which allows you to adjust the load current. The output rectifier unit converts the alternating current after the inverter into welding direct current.

The principle of operation of the welding inverter is to gradually convert the mains voltage. First, the mains AC voltage is increased and rectified in the preliminary rectifier unit. The DC voltage powers the high frequency IGBT generator in the inverter unit. The high-frequency alternating voltage is converted to a lower one by means of a transformer and fed to the output rectifier unit. From the rectifier output, current can already be supplied to the welding electrode. The electrode current is controlled by circuitry by controlling the depth of negative feedback. With the development of microprocessor technology, the production of inverter semi-automatic machines began, capable of independently choosing the operating mode and performing such functions as anti-sticking, high-frequency arc excitation, arc retention, and others.

Aluminum electrolytic capacitors in welding inverters

The main components of welding inverters are semiconductor components, a step-down transformer and capacitors. Today, the quality of semiconductor components is so high that there are no problems if they are used correctly. Due to the fact that the device operates at high frequencies and sufficiently high currents, special attention should be paid to the stability of the device - the quality of the welding work directly depends on it. The most critical components in this context are electrolytic capacitors, the quality of which greatly affects the reliability of the device and the level of interference introduced into the electrical network.

The most common are aluminum electrolytic capacitors. They are best suited for use in the primary source of a network IP. Electrolytic capacitors have a high capacitance, high voltage rating, small size, and are capable of operating at audio frequencies. Such characteristics are among the undoubted advantages of aluminum electrolytes.

All aluminum electrolytic capacitors are successively stacked layers of aluminum foil (capacitor anode), paper spacer, another layer of aluminum foil (capacitor cathode), and another layer of paper. All this is rolled up and placed in a sealed container. Conductors are removed from the anode and cathode layers for inclusion in the circuit. Also, aluminum layers are additionally pickled in order to increase their surface area and, accordingly, the capacitance of the capacitor. At the same time, the capacitance of high-voltage capacitors increases by about 20 times, and low-voltage - by 100. In addition, this entire structure is treated with chemicals to achieve the required parameters.

Electrolytic capacitors have a rather complicated structure, which makes them difficult to manufacture and operate. The characteristics of capacitors can vary greatly under different operating modes and climatic operating conditions. With increasing frequency and temperature, the capacitance of the capacitor and ESR decrease. As the temperature drops, the capacitance also drops, and the ESR can increase up to 100 times, which, in turn, reduces the maximum allowable ripple current of the capacitor. The reliability of pulse and input network filter capacitors, first of all, depends on their maximum allowable ripple current. The flowing ripple currents are capable of heating the capacitor, which causes its early failure.

In inverters, the main purpose of electrolytic capacitors is to increase the voltage in the input rectifier and smooth out possible ripples.

Significant problems in the operation of inverters are created by high currents through transistors, high requirements for the shape of control pulses, which implies the use of powerful drivers to control power switches, high requirements for the installation of power circuits, and high pulse currents. All this largely depends on the quality factor of the input filter capacitors, therefore, for inverter welding machines, it is necessary to carefully select the parameters of electrolytic capacitors. Thus, in the preliminary rectification unit of the welding inverter, the most critical element is the filtering electrolytic capacitor installed after the diode bridge. It is recommended to install the capacitor in close proximity to the IGBTs and diodes, which eliminates the influence of the inductance of the wires connecting the device to the power supply on the operation of the inverter. Also, the installation of capacitors near consumers reduces the internal resistance to alternating current of the power supply, which prevents the excitation of amplifying stages.

Typically, the filter capacitor in full-wave converters is chosen so that the rectified voltage ripple does not exceed 5 ... 10 V. It should also be borne in mind that the voltage on the filter capacitors will be 1.41 times higher than at the output of the diode bridge. Thus, if after the diode bridge we get 220 V ripple voltage, then the capacitors will already have 310 V DC voltage. Usually, the operating voltage in the network is limited to 250 V, therefore, the voltage at the filter output will be 350 V. In rare cases, the mains voltage can rise even higher, so capacitors should be selected for an operating voltage of at least 400 V. Capacitors may have additional heating due to large operating currents. The recommended upper temperature range is at least 85…105°C. Input capacitors for smoothing rectified voltage ripples are selected with a capacity of 470 ... 2500 μF, depending on the power of the device. With a constant gap in the resonant choke, an increase in the capacitance of the input capacitor proportionally increases the power delivered to the arc.

There are capacities on sale, for example, at 1500 and 2200 microfarads, but, as a rule, a capacitor bank is used instead of one - several components of the same capacity connected in parallel. Paralleling reduces internal resistance and inductance, which improves voltage filtering. Also, at the beginning of the charge, a very large charging current flows through the capacitors, close to the short-circuit current. Parallel connection allows you to reduce the current flowing through each capacitor individually, which increases the service life.

Choice of electrolytes from Hitachi, Samwha, Yageo

In the electronics market today you can find a large number of suitable capacitors from well-known and little-known manufacturers. When choosing equipment, one should not forget that with similar parameters, capacitors differ greatly in quality and reliability. The most well-proven products from such world-famous manufacturers of high-quality aluminum capacitors as, and. Companies are actively developing new technologies for the production of capacitors, so their products have better characteristics than competitors' products.

Aluminum electrolytic capacitors are available in several form factors:

• for PCB mounting;
• with reinforced snap-in terminals (Snap-In);
• with screw terminals (Screw Terminal).

Tables 1, 2 and 3 present the series of the above manufacturers, the most optimal for use in the preliminary rectifier unit, and their appearance is shown in figures 2, 3 and 4, respectively. The given series have the maximum service life (within the family of a particular manufacturer) and an extended temperature range.

Table 1 Yageo Electrolytic Capacitors

Table 2. Samwha Electrolytic Capacitors

Table 3. Hitachi Electrolytic Capacitors

As can be seen from tables 1, 2 and 3, the product range is quite wide, and the user has the opportunity to assemble a capacitor bank, the parameters of which will fully meet the requirements of the future welding inverter. The most reliable are Hitachi capacitors with a guaranteed service life of up to 12,000 hours, while competitors have this parameter up to 10,000 hours in JY series Samwha capacitors and up to 5,000 hours in Yageo LC, NF, NH capacitors. True, this parameter does not indicate a guaranteed failure of the capacitor after the specified line has elapsed. This refers only to the time of use at maximum load and temperature. When used in a smaller temperature range, the service life will increase accordingly. After the specified line, it is also possible to reduce the capacity by 10% and increase losses by 10 ... 13% when operating at maximum temperature.

Surely, when working with batteries to replace them, you needed contact welding. Since it is very undesirable to solder lithium-ion batteries with ordinary solder, there is a danger of overheating. Buying or making expensive equipment for two or three cases is definitely not profitable and costly. But such a device for resistance welding is available to absolutely everyone. After all, it essentially consists of just one part, called a supercapacitor.
This is almost the same capacitor, only high capacitance. Having all the same advantages as a conventional capacitor.

It will take

• Thick wire, with a cross section of at least 2 square meters. mm.

Manufacturing of the simplest apparatus for resistance welding from a supercapacitor

contact welding