Traditional welding machines with huge fixed transformers are gradually becoming a thing of the past. Instead, compact welding inverters have now appeared. They are easy to use, even beginners can use them. In order to find out what kind of device it is, you need to consider the design and principle of operation of the welding inverter.
About design
The device differs from traditional and more familiar transformers to every welder.
In the inverter, the processes of converting the working current occur differently. These processes proceed in stages using a small transformer, the dimensions of which are slightly larger than a pack of cigarettes. Another difference is the electronic control system. It makes the welding process easier. Thanks to the electronic system, high-quality seams are formed. This is how an inverter welding machine works. Reviews about this equipment are mostly positive. Many use it because of the compactness and quality of the seam.
General principle of operation
In the beginning220V variable frequency input currents flow through the rectifier and are then converted to DC. Additionally, the current is smoothed with a filter. Often, a traditional circuit based on electrolytic capacitors is used as it. Next, the DC voltage and current pass through a semiconductor modulator, where they again turn into AC, but with higher frequencies. In different models, this figure is different, but does not exceed 100 kHz. Then the current is rectified again and the voltage is reduced to the value necessary for welding metals. The principle of operation of the welding inverter is based on high-frequency converters. The presence of these nodes allows the use of small transformers, due to which the mass of the unit has been significantly reduced. For example, in order for an inverter welding machine to be able to deliver a current of 160 amperes, the transformer must weigh no more than 250 grams. To achieve the same result using a traditional apparatus, the transformer would have a minimum mass of 18 kilograms. This is very inconvenient.
The control unit is the main advantage of inverter welding machines
Electronics plays a very important role in the operation of this equipment. It provides feedback. This helps to fully control the electric arc, if necessary, adjust or maintain its parameters at the desired level.
The slightest deviation of the characteristics of the arc is instantly read by microprocessors. This operating principlewelding machine inverter and the presence of an electronic control unit guarantee an electric arc with the most stable characteristics. This ultimately increases the quality of welding work.
Schematic diagram
In the rectifier, alternating current with a frequency of 50 Hz and a voltage of 220 Volts passes through a powerful diode bridge. Variable frequency current ripples are smoothed out due to the presence of electrolytic capacitors in the circuit. During operation, the diode bridge is subject to overheating, so radiators are installed on the diodes. In addition, the inverter is equipped with a thermal fuse. It works if the diodes are heated to 90 degrees. The thermal fuse reliably protects the diodes. Near the diode bridge, you can see quite large powerful capacitors. Their capacitance can range from 140 to 800 microfarads. Also, the circuit necessarily contains filters that do not allow any interference during operation. We examined which welding inverter has the principle of operation.
The scheme also implies other elements. Check them out below.
Inverter: what is it
The inverter itself is built on two mosfets. These are powerful transistors. They tend to get very hot, so they are equipped with a radiator. Such semiconductor elements solve the problem of switching currents passing through a pulse transformer. Operating frequencies here can exceed several thousand kHz. As a result, a current with a variable high frequency is generated. transistors must beresistant to voltage drops. Manufacturers equip devices with special protective circuits. Often they are assembled on the basis of a circuit with resistors and capacitors. Next, the secondary winding on the step-down transformer comes into play. It has low voltages - up to 70 volts. But the current strength can be 130-140 Amperes.
Output rectifier
In order for a constant current and voltage to form at the output, reliable output rectifiers are used. This circuit is assembled on the basis of dual diodes that have a common cathode. These elements are characterized by high speed of work, they instantly open and quickly close. The response time of such diodes is about 50 nanoseconds. This speed is very important.
Diodes have to work with high-frequency currents, ordinary semiconductor elements cannot cope with this task. They simply would not have enough speed when switching. In case of repair, even knowing the device of the welding inverter, the principle of operation, it is recommended to change these diodes for elements with the same characteristics.
Design and operation of the electronic system
She is powered by voltage regulators rated at 15 volts. These elements are installed on radiators. The power supply for the board comes from the main rectifier. When voltage is applied, the capacitors are charged first. The tension is growing at this point. To protect the diode assembly, a limiting circuit with a powerful resistor was used. Whencapacitors are fully charged, the welding machine starts its work. The relay contacts close, and the resistor will no longer participate in the process.
Additional units and systems
The device and the principle of operation of the welding inverter imply the presence of other systems and components that provide the device with such high performance. So, you can highlight the control system, as well as drivers. The main element here is the PWM controller chip. It provides control of the action of powerful transistors. Also in the device there are various control and adjustment circuits. In this case, the main element is the transformer. It is needed to control the strength and other characteristics of the current after the output transformer.
The principle of operation of the welding inverter also implies the presence of a system for monitoring the voltage and characteristics of the currents at the output in the mains. This block consists of an operational amplifier based on a microcircuit. The main purpose of the system is to launch the emergency protection mode in case of urgent need. It is also designed to monitor the operation and he alth of the electronic unit.
TIG Argon Welding Machines
Inert gas welding of metals is one of the most popular manual welding methods today. Working with argon provides high quality seams due to the complete isolation of the bath. Thus, it is possible to work with any metals, even with aluminum, magnesium, titanium and their alloys. Principle of operationwelding inverter with argon is no different from an ordinary inverter. The main difference is that the process uses not only a welding power source, but also a special torch. TIG welding involves constant heating of the work area using an electric arc, which is created by means of a refractory tungsten electrode. Many people are interested to know how this type of inverter welding machine works. Let's find out.
Design of TIG welding machine
The device for argon arc welding is a power source and a special torch.
The first is needed to generate an electric arc, as well as to maintain its magnitude in normal parameters. The sheer number of metals and alloys that can be worked with in this way involves many adjustments. Today, semiconductor inverter units are used for this. This is a TIG welding inverter. The principle of operation does not differ from a conventional inverter, but the output of such a device is combined. Direct current is used to work with stainless steels, copper alloys. Variable is suitable for magnesium, aluminum and other similar alloys. The mode of operation when intermittent currents are applied is used for welding thin parts. Also included is a burner. What is it?
This is a special device in which a tungsten electrode is installed. It has a nozzle through whichargon is supplied. Unlike traditional semi-automatic welding machines, the TIG welding torch is supplied with gas before the arc is ignited. This avoids burnout of metals.
Conclusion
The affordable cost of such equipment allows you to seriously think about purchasing such a unit for the household. If you learn how to confidently use such a device, you can even earn. There is a very high demand for argon welding today. You can purchase an inexpensive domestic TIG-180 s welding inverter. The principle of operation of this device allows you to use it in manual welding mode. This is a universal solution. Its cost is from 13 to 15 thousand rubles. The cheapest Chinese models can be purchased at a price of 6 thousand rubles. Professional devices cost about 50 thousand rubles.
