For welding, starting and charging. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

For welding, starting and charging. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / welding equipment

Comments on the article

For more than ten years I have been using a home-made device that has proven itself in welding, cutting metal sheets with a thickness of 0,6 to 12 mm, supplying power while starting the car engine with a starter, charging alkaline and acid batteries, ensuring the start and subsequent operation of a DC motor power up to 1,5 kW. Moreover, the universal presented by me is also an excellent source of safe voltage for the electrical equipment of the cellar, basement, workshop ...

Main characteristics of the device

Voltage of the primary power supply, V ...... 220
Adjustable welding current, A ...... 0-120
Adjustable charging current, A ...... 0-75
Adjustable output voltage, V......0-70
Maximum power, kVA ...... 3
Overall dimensions, mm......590x310x300
Weight, kg ...... 40

At the heart of the device is a homemade power transformer T_с - single-phase, rod (cross-section of a magnetic circuit made of electrical steel 60x80 mm), with a primary winding I, which has 230 turns of copper wire with a diameter of 2 mm, two secondary (II-1 and II-2, 32 turns each, the wire cross-section in each is 32 mm²). This 25-kg large-sized (280x240x120 mm) electrical device has a winding III, with 50 turns of wire with a cross section of 40 mm².

Another massive and voluminous homemade device is the L choke_c - also wound on a core of a rod type (section 40x30 mm - half of the set of magnetic circuit T_с), but with an "air" gap formed by a 4 mm glass-textolite gasket. There are only two 60-turn windings of insulated copper wire with a diameter of 6-8 mm, connected in series.

Slightly off throttle L_c there is a block of filter capacitors of the KBGI type with a total capacity of 2000 microfarads with an operating voltage of 80V.

To match T_c and L_c - rectifier unit, which includes a pair of powerful electrical valves D200 (VD1c-VD2c) and "electric" thyristors T160 (VS1_c-VS2_c) controlled by a special block on a chip with five transistors. Of course, all used power semiconductor devices are on aluminum radiators.

Since during operation (especially when welding and cutting metal) a significant amount of heat is released,

so much the device includes a forced cooling electric fan (M1 electric motor with an impeller on the shaft). It is located in close proximity to the power transformer so that as much of the heat-radiating surface as possible falls under the air pressure.

B 50-60 mm from T_c choke L is attached_c so that the central part of its windings coincides with the central axial line of the electric fan (for better airflow). Well, the rest of the forced cooling air flow is distributed between power semiconductor devices and other elements and components of the device. The thyristor control unit is one of them. Mounted on a separate board, it is located above the inductor perpendicular to its windings (Fig. 2).

The thyristor control unit is nothing more than a phase-pulse controller for the operation of a diode-thyristor bridge, rated for a current of up to 500 A. Mounted from widely used radio components and typical industrial units, it provides high quality regulation and the possibility of reliable authorization in automatic mode .

Rice. 1. Schematic diagram of a home-made welding-charging-starting device.

For welding, starting and charging
Rice. 2. Finished device (left) and view of its layout with the rear wall removed (right).

There is also an electronic protection of the converter from non-standard situations, which is triggered by instantly blocking the output pulses. This is an electronic device based on the thyristor VS1, in the control electrode circuit of which there are emergency state sensors (for example, reed switches of current limiters, contacts of mercury thermometers and similar compact devices) connected in parallel and working to close the PROTECTION circuit (Fig. 1 shows only one pair of such contacts - SA1).

When any of the sensors of the emergency state is closed, the thyristor VS1 is unlocked, which subsequently remains open. And this means that the inverting input of the operational amplifier - the DA1 microcircuit receives a potential that exceeds all possible values of the sawtooth voltage at its non-inverting input. As a result, the output of the "opamp" is set to zero, the transistors VT3 - VT5 remain closed and the output pulses are not supplied to the thyristors.

The block is returned to its original state by briefly turning off the supply voltage of the block.

Now a few recommendations on the possible replacement of radio components. In the role of transistors VT1 and VT2, the more modern and widespread KT315 and KT312 are quite acceptable; instead of three terminal triodes (VТЗ and VT4 - VT5 operating in parallel), only two semiconductor KT829 are sufficient.

As KD105B (VD3 - VD5), any silicon diodes with a reverse voltage of at least 100 V and a direct pulse current of at least 3 A perform well. Well, the VD1 rectifier bridge (KTs402 assembly) can be safely replaced with any analog from the KTs402 - KTs405 series.

It is advisable to take the "Silovichok" T1 ready-made - such as TVK-70L2 or TVK-110L. The same should be done when choosing pulse transformers T2 and T3. Of course, the preference is for the industrial MIT-2V. However, if necessary, you can be content with self-made "pulses" wound on any standard ferrite rings with a diameter of 20-50 mm. It is only necessary that the primary winding of each transformer contains 50 turns of PEV-0,2 wire. Accordingly, in the secondary there should be 150 turns of PEV-0,2. It is recommended to highlight the beginning of each winding (for example, with a colored mark) so as not to be mistaken when desoldering in accordance with the circuit diagram, where the marks are conditionally indicated by dots.

The duration of the control pulses supplied to the thyristors is 100-200 μs.

In the author's design, the welding-charging-starting device is mounted inside a metal frame measuring 500x310x300 mm, made from a steel angle 15x15 mm. In this design, almost one after another, there are: an electric fan for forced air cooling, a power transformer, a choke, a rectifier unit, and on top (as already noted) a thyristor control unit.

The front panel is equipped with: a mains voltage switch with automatic protection, a NETWORK indicator light, a 30 V DC voltmeter, a 50 A DC electrical measuring pointer with an AMMETER-OFF toggle switch, a VOLTAGE potentiometer of the thyristor control unit, toggle switches FAN and FILTER-OFF. Below are the "+" and "-" terminals in one row for connecting both to the car battery for charging it, and to the starter to start the car engine when the battery is discharged, and in the WELDING mode - to connect the welding cable with the electrode holder and the "ground wires" during welding and metal cutting, terminals ~ 48 V. Well, under the top cover of the device there is a contact block with changeover copper tires for additional switching to the WELDING and CHARGER modes.

Based on my own experience, I recommend, when wiring the device, to achieve particularly strong contact in all electrical circuits in accordance with the electrical circuit diagram. I strongly advise you to supply power wires with copper tube tips, flatten and solder the end part of each terminal, and then drill through a hole with a diameter of 6,5 mm for mounting bolts. Moreover, all bolted connections should be equipped with Grover washers for better tightening and obtaining a tight electrical contact. This is especially true for the electrical connections of the power transformer, inductor and rectifier unit.

As for the order of work on the welding-charging-starting device, here, as they say, there are no problems.

In particular, when performing welding operations (WELDING mode), it is required to insert the plug of the power cord into the socket (making sure that the phase wire actually goes to the circuit breaker - for quick and accurate operation of electrical protection in case of overload and short circuit). When the machine A1 is turned on, the POWER indicator light should light up. Then you need to connect the "ground wire" (extending from the part prepared for welding) to the "-" terminal, and the welding cable (coming from the electrode holder) to the "+" terminal.

Turning on the air cooling fan of the device, you should turn off the ammeter, which, otherwise, may fail. It remains to insert the electrode into the holder, select the adjustment of the valve bridge for the required current with the VOLTAGE potentiometer and proceed to welding.

For the CHARGER mode, the algorithm is somewhat different. Here it is already necessary to connect the corresponding leads from the battery to the terminals of the device "+" and "-", and adjust the "trolleybus" thyristors with the help of the VOLTAGE potentiometer so that the rectifier supplies the required charging current.

START differs from the CHARGER mode in that an increased current of up to 50 A is supplied to the battery terminals for several seconds while the car starter is turned on.

Author: A. Shikhansky, Volsk

See other articles Section welding equipment.

<< Back

Latest news of science and technology, new electronics:

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

The threat of space debris to the Earth's magnetic field 01.05.2024

More and more often we hear about an increase in the amount of space debris surrounding our planet. However, it is not only active satellites and spacecraft that contribute to this problem, but also debris from old missions. The growing number of satellites launched by companies like SpaceX creates not only opportunities for the development of the Internet, but also serious threats to space security. Experts are now turning their attention to the potential implications for the Earth's magnetic field. Dr. Jonathan McDowell of the Harvard-Smithsonian Center for Astrophysics emphasizes that companies are rapidly deploying satellite constellations, and the number of satellites could grow to 100 in the next decade. The rapid development of these cosmic armadas of satellites can lead to contamination of the Earth's plasma environment with dangerous debris and a threat to the stability of the magnetosphere. Metal debris from used rockets can disrupt the ionosphere and magnetosphere. Both of these systems play a key role in protecting the atmosphere and maintaining ... >>

Solidification of bulk substances 30.04.2024

There are quite a few mysteries in the world of science, and one of them is the strange behavior of bulk materials. They may behave like a solid but suddenly turn into a flowing liquid. This phenomenon has attracted the attention of many researchers, and we may finally be getting closer to solving this mystery. Imagine sand in an hourglass. It usually flows freely, but in some cases its particles begin to get stuck, turning from a liquid to a solid. This transition has important implications for many areas, from drug production to construction. Researchers from the USA have attempted to describe this phenomenon and come closer to understanding it. In the study, the scientists conducted simulations in the laboratory using data from bags of polystyrene beads. They found that the vibrations within these sets had specific frequencies, meaning that only certain types of vibrations could travel through the material. Received ... >>

Random news from the Archive

The composition of the intestinal microflora 06.05.2016

In 95% of people, 14 main groups of microbes are represented in the intestinal microflora, which make up the "core" of the human microbiome. This conclusion was reached by the authors of two international studies: one led by Professor Jeroen Raes from the University of Leuven (Belgium), and the second led by Dr. Alexandra Zhernakova from the University of Groningen (Netherlands).

The methodology for both studies was the same: volunteers (1106 in Belgium and 1135 in the Netherlands) gave stool samples, blood tests, completed a detailed questionnaire about their health and lifestyle, and also underwent some additional medical tests. Analysis of the collected data allowed scientists to identify 600 groups of microbes that inhabit the bodies of people, of which 14, as mentioned above, turned out to be practically a common "core".

Comparison of the composition of the microflora with the results of other tests also gave interesting results. Previously, it was thought that the composition of the human microflora is influenced mainly by such factors as whether a person was born naturally or by caesarean section, the duration of his breastfeeding and body mass index. However, it has now turned out that these factors together have only 20% of the impact on the diversity of microbes living in our intestines.

The key factors turned out to be quite different. These are the medications we take - including heartburn medications, antibiotics and statins - the efficiency of our breathing, stool consistency and age.

Both research teams set out to find one key factor that would serve as a good indicator of the overall health of our microbiome. The results were different. The first, "Belgian" group found a correlation between this indicator and the rate of passage of feces through the intestines, i.e., stool. The second, "Dutch" team identified another factor: it is the protein chromogranin A, which signals the stressful activation of the nervous and endocrine systems of the body. Its reduced concentration in human blood corresponds to a more diverse microflora, the scientists write.

In any case, these new data force us to reconsider the existing ideas about the composition of the microbiome of our body and what factors influence it. The discoveries made are of great importance for practical medicine.

Other interesting news:

▪ stem cell management

▪ Amorphous graphene synthesis technology for wearable electronics

▪ The electronic cigarette will check the age of the smoker

▪ Ocean acidification is detrimental to coral reefs

▪ Transmission of radio signals with almost no energy consumption

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site House, household plots, hobbies. Article selection

▪ article Potemkin villages. Popular expression

▪ article Where can I listen to the organ played by the waves and the wind? Detailed answer

▪ article Cashier of the trading floor. Job description

▪ article Repair of rubber sleeves. Simple recipes and tips

▪ article Water from nowhere. Focus Secret

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews