DIY semi-automatic - detailed video

Created plan

Any scheme homemade device provides a separate sequence of work:

• At the initial level, it is necessary to ensure preparatory purging of the system. It will accept the subsequent supply of gas;
• The arc power source must then be started;
• Feed wire;
• Only after all actions have been completed will the inverter begin to move at the specified speed.
• At the final stage, the seam should be protected and the crater welded;

Control board

To create an inverter, a special control board is required. This device must have the following components installed:

• A master oscillator including a galvanic isolation transformer;
• The node with which the relay is controlled;
• Feedback blocks responsible for mains voltage and supply current;
• Thermal protection block;
• Antistick block;

Case selection

Before assembling the unit, you need to select the housing. You can choose a box or box with suitable dimensions. It is recommended to choose plastic or thin sheet material. Transformers are built into the housing and connected to the secondary and primary bobbins.

Coil alignment

The primary windings are made according to parallel circuit. Secondary bobbins are connected in series. According to a similar circuit, the device is capable of accepting a current of up to 60 A. In this case, the output voltage will be equal to 40 V. These characteristics are ideal for welding small structures at home.

Cooling system

During continuous operation homemade inverter may overheat greatly. Therefore, such a device needs special system cooling. The most simple method To create cooling is to install fans. These devices must be attached to the sides of the case. Fans should be installed opposite transformer device. The mechanisms are attached in such a way that they can work for extraction.

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On sale you can see many semi-automatic welding machines of domestic and foreign production, used in the repair of car bodies. If you wish, you can save on costs by collecting semiautomatic welding machine in garage conditions.

Wire feed speed regulator for semi-automatic welding machine

Included welding machine includes a housing, in the lower part of which a power transformer of single-phase or three-phase design is installed, above is a device for drawing the welding wire.

The device includes an electric motor DC with a speed reduction transmission mechanism, as a rule, an electric motor with a gearbox from a UAZ or Zhiguli windshield wiper is used here. Steel wire with copper coating from the feed drum, passing through rotating rollers, enters the wire supply hose, at the exit the wire comes into contact with a grounded product, the resulting arc welds the metal. To isolate the wire from atmospheric oxygen, welding occurs in an inert gas environment. To turn on the gas installed solenoid valve. When using a prototype of a factory semi-automatic machine, some shortcomings were identified that impede high-quality welding. This is a premature failure of the output transistor of the electric motor speed controller circuit due to overload and the absence in the budget circuit of an automatic engine braking system upon a stop command. When switched off, the welding current disappears, and the motor continues to feed wire for some time, which leads to excessive wire consumption, the risk of injury, and the need to remove excess wire with a special tool.

In the laboratory "Automation and Telemechanics" of the Irkutsk Regional CDTT, more modern scheme wire feed regulator, the fundamental difference of which from the factory ones is the presence of a braking circuit and a double supply of the switching transistor for starting current with electronic protection.

Included schematic diagram The wire feed regulator includes a current amplifier using a powerful field-effect transistor. A stabilized speed setting circuit allows you to maintain power in the load regardless of the mains supply voltage; overload protection reduces burning of the electric motor brushes during startup or jamming in the wire feeder and failure of the power transistor.

The braking circuit allows you to stop the engine rotation almost instantly.

The supply voltage is used from a power or separate transformer with a power consumption not lower than the maximum power of the wire drawing motor.

The circuit includes LEDs to indicate the supply voltage and operation of the electric motor.

Device characteristics:

• supply voltage, V – 12…16;
• electric motor power, W – up to 100;
• braking time, sec - 0.2;
• start time, sec - 0.6;
• adjustment
• revolutions,% - 80;
• starting current, A - up to 20.

Step 1. Description of the semiautomatic welding regulator circuit

The electrical circuit diagram of the device is shown in Fig. 1. The voltage from the speed controller of the electric motor R3 through the limiting resistor R6 is supplied to the gate of the powerful field-effect transistor VT1. The speed controller is powered from the analog stabilizer DA1, through the current-limiting resistor R2. To eliminate interference possible from turning the slider of resistor R3, a filter capacitor C1 is introduced into the circuit.
The HL1 LED indicates the on state of the welding wire feed regulator circuit.

Resistor R3 sets the feed speed of the welding wire to the arc welding site.

Trimmer resistor R5 allows you to select best option regulation of engine rotation speed depending on its power modification and power source voltage.

Diode VD1 in the circuit of voltage stabilizer DA1 protects the microcircuit from breakdown if the polarity of the supply voltage is incorrect.
Field-effect transistor VT1 is equipped with protection circuits: a resistor R9 is installed in the source circuit, the voltage drop across which is used to control the voltage at the gate of the transistor using comparator DA2. At a critical current in the source circuit, the voltage through the trimming resistor R8 is supplied to control electrode 1 of the comparator DA2, the anode-cathode circuit of the microcircuit opens and reduces the voltage at the gate of transistor VT1, the speed of the electric motor M1 will automatically decrease.

To eliminate the operation of protection against pulse currents that occur when the motor brushes spark, capacitor C2 is introduced into the circuit.
A wire feed motor with collector spark reduction circuits SZ, C4, C5 is connected to the drain circuit of transistor VT1. A circuit consisting of diode VD2 with load resistor R7 eliminates reverse current pulses from the electric motor.

The two-color LED HL2 allows you to control the state of the electric motor: when lit green - rotation, when lit red - braking.

The braking circuit is based on electromagnetic relay K1. The capacitance of filter capacitor C6 is selected to be small - only to reduce vibrations of the armature of relay K1; a large value will create inertia when the electric motor is braking. Resistor R9 limits the current through the relay winding when the power supply voltage is increased.

The principle of operation of braking forces, without the use of rotation reversal, is to load the reverse current of the electric motor when rotating by inertia, when the supply voltage is turned off, onto a constant resistor R11. The recovery mode - transferring energy back to the network allows you to stop the motor in a short time. At a complete stop, the speed and reverse current will be set to zero, this happens almost instantly and depends on the value of resistor R11 and capacitor C5. The second purpose of capacitor C5 is to eliminate burning of contacts K1.1 of relay K1. After supplying mains voltage to the regulator control circuit, relay K1 will close the electric motor power supply circuit K1.1, drawing the welding wire will resume.

The power source consists of a network transformer T1 with a voltage of 12...15 V and a current of 8...12 A, the diode bridge VD4 is selected for double current. If the semi-automatic welding transformer has a secondary winding of the appropriate voltage, power is supplied from it.

Step 2. Details of the semiautomatic welding regulator circuit

The wire feed regulator circuit is made on printed circuit board made of single-sided fiberglass 136*40 mm in size (Fig. 2), except for the transformer and motor, all parts are installed with recommendations for possible replacement. The field-effect transistor is installed on a radiator with dimensions of 100*50*20 mm.

Field effect transistor analogue of IRFP250 with a current of 20...30 A and a voltage above 200 V. Resistors type MLT 0.125; resistors R9, R11, R12 are wire-wound. Resistors R3, R5 should be installed as SP-ZB type. The type of relay K1 is indicated in the diagram or No. 711.3747-02 for a current of 70 A and a voltage of 12 V, their dimensions are the same and are used in VAZ cars.

Comparator DA2, with a decrease in stabilization of speed and protection of the transistor, can be removed from the circuit or replaced with a zener diode KS156A. The VD3 diode bridge can be assembled using Russian diodes of type D243-246, without radiators.

The DA2 comparator has a complete analogue of the foreign-made TL431CLP.

Electromagnetic valve for inert gas supply Em.1 is standard, with a supply voltage of 12 V.

Step 3. Adjustment of the semiautomatic welding regulator circuit

The adjustment of the wire feed regulator circuit of a semi-automatic welding machine begins with checking the supply voltage. Relay K1 should operate when voltage appears, producing a characteristic clicking sound from the armature.

By increasing the voltage at the gate of field-effect transistor VT1 with the speed regulator R3, make sure that the speed begins to increase at the minimum position of the resistor R3 slider; if this does not happen, adjust the minimum speed with resistor R5 - first set the slider of resistor R3 to the lower position, with a gradual increase in the value of resistor R5, the engine should reach the minimum speed.

Overload protection is set by resistor R8 during forced braking of the electric motor. When the field effect transistor is closed by the comparator DA2 due to overload, the HL2 LED will go out. Resistor R12 can be excluded from the circuit when the power supply voltage is 12…13 V.
The scheme has been tested on different types electric motors with similar power, the braking time mainly depends on the mass of the armature, due to the inertia of the mass. The heating of the transistor and diode bridge does not exceed 60°C.

The printed circuit board is fixed inside the body of the semi-automatic welding machine, the engine speed control knob - R3 is displayed on the control panel along with indicators: power on HL1 and two-color engine operation indicator HL2. Power to the diode bridge is supplied from a separate winding of the welding transformer with a voltage of 12 ... 16 V. The inert gas supply valve can be connected to capacitor C6, it will also turn on after the mains voltage is applied. Power supply of power networks and electric motor circuits stranded wire in vinyl insulation with a cross section of 2.5...4 mm2.

Starting circuit of a semi-automatic welding machine

Characteristics of the semi-automatic welding machine:

• supply voltage, V - 3 phases * 380;
• primary phase current, A - 8...12;
• secondary no-load voltage, V - 36...42;
• no-load current, A - 2...3;
• no-load arc voltage, V - 56;
• welding current, A - 40...120;
• voltage regulation, % — ±20;
• ON duration, % - 0.

The wire is fed into the welding zone in a semi-automatic welding machine using a mechanism consisting of two steel rollers rotating in opposite directions by an electric motor. To reduce speed, the electric motor is equipped with a gearbox. From the conditions for smooth adjustment of the wire feed speed, the rotation speed of the DC electric motor is additionally changed by the semiconductor wire feed speed controller of the semiautomatic welding machine. An inert gas, argon, is also supplied to the welding zone to eliminate the effect of air oxygen on the welding process. The mains power supply for the semi-automatic welding machine is made from a single-phase or three-phase electrical network; a three-phase transformer is used in this design; recommendations for power supply from a single-phase network are indicated in the article.

Three-phase power allows the use of a smaller winding wire than when using a single-phase transformer. During operation, the transformer heats up less, voltage ripple at the output of the rectifier bridge is reduced, and the power line is not overloaded.

Step 1. Operation of the semi-automatic welding starting circuit

Switching the connection of power transformer T2 to the electrical network occurs using triac switches VS1 ... VS3 (Fig. 3). Choosing triacs instead of a mechanical starter allows you to eliminate emergency situations when contacts break and eliminates the sound from the “clapping” of the magnetic system.
Switch SA1 allows you to disconnect the welding transformer from the network during maintenance work.

The use of triacs without radiators leads to their overheating and random switching on of the semi-automatic welding machine, so triacs must be equipped with budget radiators 50*50 mm.

It is recommended to equip the semi-automatic welding machine with a fan with a 220 V power supply; its connection is parallel to the network winding of the T1 transformer.
The three-phase transformer T2 can be used ready-made, with a power of 2...2.5 kW, or you can buy three transformers 220 * 36 V 600 VA, used for lighting basements and metal-cutting machines, and connect them in a star-star configuration. During production homemade transformer the primary windings must have 240 turns of PEV wire with a diameter of 1.5 ... 1.8 mm, with three taps 20 turns from the end of the winding. The secondary windings are wound with a copper or aluminum busbar with a cross-section of 8...10 mm2, the number of PVZ wires is 30 turns.

Taps on the primary winding allow you to adjust the welding current depending on the mains voltage from 160 to 230 V.
Use in a single-phase circuit welding transformer allows the use of an internal electrical network used to power home electric furnaces with an installed power of up to 4.5 kW - the wire suitable for the outlet can withstand current up to 25 A, there is grounding. The cross-section of the primary and secondary windings of a single-phase welding transformer should be increased by 2...2.5 times in comparison with the three-phase version. A separate grounding wire is required.

Additional regulation of the welding current is carried out by changing the delay angle of the triacs. Using semiautomatic welding machines in garages and summer cottages does not require special network filters to reduce impulse noise. When using a semiautomatic welding machine in living conditions it should be equipped with a remote noise filter.

Smooth control of the welding current is carried out using an electronic unit on a silicon transistor VT1 when the SA2 “Start” button is pressed - by adjusting the resistor R5 “Current”.

The T2 welding transformer is connected to the electrical network using the SA2 “Start” button located on the welding wire feed hose. The electronic circuit opens the power triacs through optocouplers, and the mains voltage is supplied to the network windings of the welding transformer. After voltage appears on the welding transformer, a separate wire feed unit is turned on, the inert gas supply valve opens, and when the wire coming out of the hose touches the part being welded, a electric arc, the welding process begins.

Transformer T1 is used for power supply electronic circuit starting the welding transformer.

When supplying mains voltage to the anodes of the triacs through an automatic three-phase circuit breaker SA1, transformer T1 for powering the electronic starting circuit is connected to the line, the triacs are in the closed state at this time. The voltage of the secondary winding of transformer T1, rectified by the diode bridge VD1, is stabilized by the analog stabilizer DA1 for stable operation of the control circuit.

Capacitors C2, SZ smooth out the ripples of the rectified supply voltage of the starting circuit. The triacs are switched on using the key transistor VT1 and triac optocouplers U1.1 ... U1.3.

The transistor is opened by a voltage of positive polarity from the analog stabilizer DA1 through the “Start” button. The use of low voltage on the button reduces the likelihood of injury to the operator by high voltage in the electrical network in case of damage to the wire insulation. The current regulator R5 regulates the welding current within 20 V. Resistor R6 does not allow reducing the voltage on the network windings of the welding transformer by more than 20 V, at which the level of noise in the electrical network sharply increases due to distortion of the voltage sinusoid by triacs.

Triac optocouplers U1.1…U1.3 perform galvanic isolation of the electrical network from the electronic control circuit and allow a simple method to regulate the opening angle of the triac: the greater the current in the LED circuit of the optocoupler, the smaller the cutoff angle and the greater the current of the welding circuit.
The voltage to the control electrodes of the triacs is supplied from the anode circuit through an optocoupler triac, a limiting resistor and a diode bridge, synchronously with the network phase voltage. Resistors in the optocoupler LED circuits protect them from overload at maximum current. Measurements showed that when starting at maximum welding current, the voltage drop across the triacs did not exceed 2.5 V.

If there is a large variation in the switching slope of triacs, it is useful to shunt their control circuits to the cathode through a resistance of 3...5 kOhm.
An additional winding is wound on one of the power transformer rods to power the wire feed unit with 12 V AC voltage, which must be supplied with voltage after the welding transformer is turned on.

The secondary circuit of the welding transformer is connected to a three-phase DC rectifier using diodes VD3...VD8. Installation of powerful radiators is not required. The circuit connecting the diode bridge with capacitor C5 is made with a copper bus with a cross section of 7 * 3 mm. Choke L1 is made of iron from a power transformer for tube TVs of the TS-270 type; the windings are first removed, and in their place a winding with a cross-section of at least 2 times the secondary is wound until it is filled. Place a gasket made of electrical cardboard between the halves of the transformer iron of the inductor.

Step 2. Installation of the semi-automatic welding starting circuit

The starting circuit (Fig. 3) is mounted on a circuit board (Fig. 4) measuring 156*55 mm, except for the elements: VD3...VD8, T2, C5, SA1, R5, SA2 and L1. These elements are fixed to the body of the semi-automatic welding machine. The circuit does not contain indication elements; they are included in the wire feed unit: power-on indicator and wire feed indicator.

The power circuits are made of insulated wire with a cross-section of 4...6 mm2, the welding circuits are made of copper or aluminum busbar, the rest are made of vinyl insulated wire with a diameter of 2 mm.

The polarity of the holder connection should be selected based on the welding or surfacing conditions when working with metal with a thickness of 0.3...0.8 mm.

Step 3. Setting up the start-up circuit for the semi-automatic welding machine

Adjustment of the starting circuit of the semi-automatic welding machine begins with checking the voltage of 5.5 V. When you press the “Start” button on capacitor C5, the no-load voltage should exceed 50 V DC, and under load - at least 34 V.

At the triac cathodes, relative to the network zero, the voltage should not differ by more than 2...5 V from the voltage at the anode; otherwise, replace the triac or optocoupler of the control circuit.

If the mains voltage is low, switch the transformer to low voltage taps.

When setting up, you should follow safety precautions.

Download printed circuit boards:

In this article we will tell you how to make a semi-automatic welding machine with your own hands? The main thing that is needed for this is enthusiasm. After reading the theoretical information, you can begin assembly. To begin with, I would like to clarify what is the difference between a semi-automatic welding machine and a machine that works with electrodes.

When is it carried out? manual welding, the load current must be constant, and in automatic, the main thing is voltage stability. This is if in general outline. We will manufacture a universal device, i.e. automatic with arc welding (MAG/MMA).

Feed mechanism

Assembly should begin with the wire feed and tension mechanism. To assemble the mechanical part, you will have to use a pair of bearings (size 6202), an electric motor from car wipers (the smaller the motor, the better).

When choosing a motor, make sure that it rotates in one direction, and not “from side to side”. In addition, you will need to grind or find somewhere a roller with a diameter of 25 mm. This roller sits on top of the thread on the electric motor shaft. Each non-standard detail must be made by hand, fortunately, there is nothing complicated there.

The design of the feed mechanism consists of two plates on which the bearings are fixed, and a roller on the electric motor shaft, located in the middle. The plates are compressed and the bearings are pressed against the roller using a spring. From one bearing to the roller, a wire is drawn, threaded inside the “guides” on both sides of the rollers.

Installation is carried out on top of a textolite plate, the thickness of which is 5 mm. This is done so that the wire comes out where there will be a connector into which the welding sleeve attached to the front of the body is connected. We also install a reel on which the wire is wound on the PCB. We grind a shaft under the coil, which is installed at an angle of 90° to the plate, which has a thread on the edge to fix the latter.

The design of the semi-automatic do-it-yourself reference machine is simple and reliable, approximately the same as is used for industrial devices. The parts in the feed mechanism are designed for a regular coil, but welding will be carried out without gas; it’s good that welding wire is sold everywhere.

What should happen is shown at the top at the beginning of the article. Reinforcing the computer case is done using two corners on those sides where the electronic part of the device is supposed to be installed. The rear wall of the case has a power supply and a device that regulates the frequency at which the electric motor rotates.

Semi-automatic wire feeding diagram

A transformer is quite suitable for these purposes. It is the simplest and most reliable method of powering an electric motor. Most optimal scheme Feed rate control is thyristor. Below you can see the electrical circuit with which the feed motor is controlled.

Feeder PCB

This circuit does not have a smoothing capacitor; this is how the thyristor is controlled. The diode bridge can be anything, the main thing is that the current exceeds 10A. We use BTB16 with a flat case as a thyristor; it can be replaced with KU202 (any letter). The transformer, which contains a semi-automatic do-it-yourself welding machine, must have a power exceeding 100W.

Another option for wire feed speed controller

Welding technologies are becoming more and more accessible, so everyone can now buy a simple inverter, and more practical buyers. It would take a very long time to list the advantages of this technology, but in practice, owners are not always happy with their purchase. This is due to the fact that people simply do not know how to set up a semi-automatic welding machine. We have analyzed the main functions of budget and middle-class devices in order to use an example of their capabilities to explain how a semi-automatic device is adjusted.

Adjustment of current, voltage, wire feed speed and other parameters is carried out immediately before welding; during the work, the welder makes additional adjustments to the work. However, there are a number of requirements and settings that must be completed before starting work, these are

• preparing the welding machine;
• as well as the conditions of the work performed.

Thus, the device must be connected to a protective gas supply system (carbon dioxide, argon or mixtures of gases). IN mandatory you need to make sure there is enough in the drum, and if necessary, fill in a new one and stretch it to the working handle.

To correctly set the primary welding parameters you need to know:

• the thickness of the parts being welded and their composition (stainless steel, steel, etc.);
• (horizontal, vertical and others);
• wire thickness.

Device settings

When everything is ready, you can begin the actual settings. Despite the fact that experienced welders can set the modes at their own discretion, we will build on the recommended parameters. The values ​​presented in the table below are averaged and in each individual case, for best quality work, it is worth making a small adjustment. How to do this, why this or that parameter is needed, we will consider further.

Table of approximate welding conditions for carbon steels

Gas flow rate

Although this parameter does not relate to setting up a semi-automatic welding machine, it plays an important role in the welding process. Modern gas cylinder equipment is equipped with convenient gearboxes, where the flow rate is indicated in liters. Just set the value to 6 - 16 liters, and that's it.

Voltage

This parameter conditionally shows how much heat we will give to work in at the moment. As can be seen from the table, the thicker the metal, the greater the Voltage, which means heating and melting occurs faster and easier. The difficulty in selecting voltage arises when we are dealing with non-standard metal or a special welding design. If we are talking about working with non-ferrous or high-alloy metals, then the optimal Voltage values ​​can be found on the Internet.

On the other hand, some manufacturers do not indicate the exact value of this adjustment, but limit themselves to conditional indications, for example, numbers 1-10. In this case, you should carefully study the accompanying documentation, which should indicate the correspondence of the current position to the current voltage.

Thus, this parameter should be set according to the table “setting up a semi-automatic welding machine” or the manufacturer’s recommendations.

Wire feed speed/current

The second setting parameter for any semi-automatic machine is speed combined with current strength. This is due to the fact that both parameters are interrelated and by increasing the feed rate, the current strength increases. Some advanced machines have separate semi-automatic current controls, but they are of a professional level.

In more advanced models, the wire feed speed can be fine-tuned

As before, to begin with, we set the recommended values, however, during the process of work, this setting can and should be adjusted to suit your needs. The discrepancy is easy to spot. If the seam leads, strong deposits or shears are formed, then the speed is too high. If the roller “sags”, wavy depressions or tears appear, then the speed is too low.

By adding or decreasing the feed rate, you should achieve perfect shape roller without bulges or subsidence of the seam.

Most of the simplest devices have exactly two settings - voltage and feed speed, combined with current strength. By skillfully managing them, you can fully appreciate the quality.

Additional options

In addition to the simplest devices, there are also more advanced models with advanced functionality on the market. Let's look at their capabilities and why additional settings are needed.

Inductance (arc setting)

The most popular function, which is actively being implemented even in budget-class welding, is inductance adjustment. The parameter allows you to control the rigidity of the arc and change the characteristics of the weld. Thus, with minimal inductance, the arc temperature and penetration depth are noticeably reduced, and the weld is more convex. This setting helps welding fine details, as well as metals sensitive to overheating. At maximum inductance, the melting temperature increases, the bath becomes more liquid, and the penetration depth is maximum. The bead of such a seam is smooth, without bulges. This mode is used for melting thick metal, working in .

Knowing how the arc reacts to changes in inductance, the welder can independently control the penetration depth and bath temperature to improve the quality of work and create more reliable critical connections.

High/low speed

The switch, which is marked as High/Low, in most models is responsible for more precise adjustment of the wire feed speed. We already know that every semi-automatic machine contains a similar regulator, but if your device can work with 0.6 and 1.4 mm wire, the boundary marks will be very different. That is why, when working with thin material, the toggle switch is set to the High position and the wire generally feeds faster, while the Low position is suitable for thick solder.

Pay attention! Now there are hundreds of products on the market from dozens of different manufacturers, so in order to be sure what functionality a given model has, what this or that regulator and switch is responsible for, you should carefully study the operating instructions.

A very popular question that worries every welding beginner. First of all, let's note a list of things that affect the quality of work:

• different fillings of semi-automatic welding machines;
• power supply quality;
• alloy composition;
• ambient temperature;
• thickness and grade of wire;
• spatial positions of work;
• composition of the gas or its mixture.

In total, in order to obtain a high-quality seam, the welder has to “get into” the optimal settings with which it is possible to weld products with high quality. But as soon as you take a different metal, change the position, or the network voltage drops, you need to look for those optimal settings again.

Common mistakes and ways to solve them

1. Loud “crackling” noise during operation. Distinct clicks indicate a low solder feed rate. Increase this parameter until the operating sound becomes normal.
2. Heavy splashing. Spattering often occurs when there is insufficient insulating gas. Check the reducer, if necessary, increase the gas supply.
3. Lack of penetration and burns are eliminated by adjusting the Voltage, as well as adjusting the inductance (if any).
4. Sharp peaks or uneven bead width. Both problems are related to the position and speed of the torch. In addition to welding settings, pay attention to your own work technique.

Conclusion

This is a semi-automatic indispensable assistant in any home or garage, but to get the most out of its capabilities you need to pay due respect to the study. Thanks to this article, you know how to set up a semi-automatic welding machine. Don’t be afraid to experiment, look for exactly those parameters at which it will be convenient for you to weld the part and get a reliable seam.

The malfunction of this unit leads to significant failures in working with the semi-automatic machine, loss of working time and hassle with replacing the welding wire. The wire at the exit from the tip gets stuck, so you have to remove the tip and clean the contact part for the wire. The malfunction is observed with any diameter of the welding wire used. Or a large feed may occur, when the wire comes out in large portions when the power button is pressed.

Malfunctions are often caused by the mechanical part of the wire feed regulator itself. Schematically, the mechanism consists of a pressure roller with an adjustable degree of wire pressure, a feed roller with two grooves for wire 0.8 and 1.0 mm. A solenoid is mounted behind the regulator, which is responsible for shutting off the gas supply with a delay of 2 seconds.

The feed regulator itself is very massive and is often simply attached to the front panel of the semi-automatic machine with 3-4 bolts, essentially hanging in the air. This leads to distortions of the entire structure and frequent malfunctions. Actually, it is quite simple to “cure” this drawback by installing some kind of stand under the wire feed regulator, thereby fixing it in the working position.

On factory-made semi-automatic machines, in most cases (regardless of the manufacturer), carbon dioxide is supplied to the solenoid through a dubious thin hose in the form of a cambric, which simply “blews” from the cold gas and then cracks. This also causes work to stop and requires repairs. Based on their experience, experts advise replacing this supply hose with a car hose used to supply brake fluid from the reservoir to the brake master cylinder. The hose can withstand pressure perfectly and will serve indefinitely.

The industry produces semi-automatic machines with a welding current of about 160 A. This is sufficient when working with automotive iron, which is quite thin - 0.8-1.0 mm. If you have to weld, for example, elements made of 4 mm steel, then this current is not enough and the penetration of the parts is not complete. For these purposes, many craftsmen purchase an inverter, which, together with a semi-automatic device, can produce up to 180A, which is quite enough to guarantee a welded seam of parts.

Many people try with their own hands, through experiments, to eliminate these shortcomings and make the operation of the semi-automatic device more stable. Quite a lot of schemes and possible improvements to the mechanical part have been proposed.

One of these proposals. This is a modified and operationally tested wire feed speed regulator for a semi-automatic welding machine, a circuit proposed on an integrated stabilizer 142EN8B. Thanks to the proposed scheme of operation of the wire feed regulator, it delays the feed for 1-2 seconds after the gas valve is activated and brakes it as quickly as possible at the moment the power button is released.

The downside of the circuit is the decent power supplied by the transistor, heating the cooling radiator during operation to 70 degrees. But all this is plus the reliable operation of both the wire feed speed regulator itself and the entire semi-automatic device as a whole.

Read also

industrika.ru

Blueweld 4.165 wire feed regulator burnt out - Community "Electronic Crafts" on DRIVE2

Help me figure it out, I can’t fix a burnt-out regulator on a semi-automatic device! A new one from Italy must be ordered, they promise to deliver 90 days(((.

The power input and the output to the welding wire feed regulator motor were mixed up, and the regulator stopped working.

Here's the diagram I found:

Wire feed regulator diagram

As I understand it, the HEF 4069 UB chip contains an adjustable frequency generator that opens the mosfet at different frequencies. The plus input and output of the regulator are connected and are regulated by ground. This circuit works as a PWM generator. The mosfet opens and powers the motor.

The peculiarity of the circuit is a fairly high supply voltage - from 42 to 55 volts. Measured it on a welder.

It was visually clear that the resistors below the mosfet, circled in red, were damaged. I decided to replace them, and since I couldn’t find an SMD, I installed the regular ones at 1 ohm. I also replaced the mosfet.

I rang the diodes and they were all alive. I checked the transitions of the transistor - the transitions are ringing. Here is a diagram of the welder.

Diagram of semi-automatic welding machine Blueweld Combi 4.165

I supply power: the current is not regulated. The mosfet is completely open. The voltage at the output of the regulator is equal to the voltage at the input. The zener diode has 12 volts.

I changed the microcircuit. Nothing has changed.

Where to dig? Today I’ll use an oscilloscope to measure the frequency at the input to the mosfet, from the frequency generator, but I think if it’s open there’s a unit hanging there...

view from the parts

view from the board side.

UPD: 1. Apparently the frequency generator started working after replacing the microcircuit. But the output voltage still does not change - the mosfet is open all the time! I connected an oscilloscope. pulses with an amplitude of 11 volts arrive at the Gate mosfet leg.

The oscillogram shows how the pulse width changes depending on the position of the resistor slider.

Regulator position - minimum feed

Middle position.

Maximum feed.

For some reason the mosfet doesn't work.

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ROTATION SPEED REGULATOR FOR SEMI-AUTOMATIC WELDING ENGINE FEEDING WIRE.

ROTATION SPEED REGULATOR FOR SEMI-AUTOMATIC WELDING ENGINE FEEDING WIRE. Everyone who is involved in the repair of semi-automatic welding machines designed for welding in an environment carbon dioxide,during bodywork cars, they know that this is the most unreliable component of the welding unit, including industrial machines. A control circuit for the motor of feeding wire into the welding environment using an integrated stabilizer 142EN8B is proposed. The unit must provide a wire feed delay of 1-2 seconds after turning on the gas valve and the fastest possible braking after releasing the welding voltage switch button, which is what this device does.

I would like to draw your attention to the cheapest and very effective principle braking the engine by closing the motor armature winding with relay contacts. The disadvantage of this circuit is the fairly large power dissipated by the VT1 transistor. The 10X10cm needle radiator heats up to 70 degrees during operation. But in general the circuit turned out to be very reliable.

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Many types of welding equipment are expensive. The most convenient is a semi-automatic welding machine (SPA), which is multifunctional. The operating principle of a semi-automatic welding machine depends on its correct settings. Semi-automatic welding machines are universal and practical. Their use in the domestic economy is widespread.

Scheme of an inverter semi-automatic welding machine.

In everyday life and industry, SPA is used to produce effective welding. Execution welding work using semi-automatic machines is based on high-quality welding of non-ferrous and ferrous metals without the use additional elements. The welding process uses carbon dioxide or argon, which are protected by the use of a melting type of solid wire.

What are the requirements for the preliminary welding stage?

Basic semi-automatic welding modes.

Powerful welding equipment should be used while observing safety precautions. SPA is a source of danger because it can infect electric shock. Incorrect use of the equipment may result in fire.

Incorrect configuration of a semi-automatic machine can lead to damage to some parts of its design. All of these preliminary steps must precede mechanized welding using this device. The idle mode of operation of the spa should not be associated with the delivery of voltage to the tip of the hose.

Before starting work, the grounded terminal is connected to the SPA. Then you should adjust the power parameters, as well as the welding wire feed speed. Setting options are provided according to the thickness and type of metal. There are tables indicating all welding parameters using SPA. They can be found in specialized literature describing the welding process.

List of possible malfunctions of the welding inverter.

Setting up the SPA involves mandatory monitoring of the voltage on the welding wire, that is, the electrode. The control process of a semi-automatic device assumes appropriate logic based on the following circuit for removing and supplying voltage to the SPA:

1. Removal from microswitch.
2. Engine supply.
3. It flows to the reverse winding of the motor.
4. Receiving it with a sleeve and gas cutoff.

Having studied all the safety requirements and special instructions in books, they proceed to working with a semi-automatic device. First, you should connect it to the electrical network and press the power button. The trigger of the device should be pressed when the face is protected by a special mask.

First you need to cut off the excess wire, leaving about 3 mm, counting from the end of the burner. After the arc appears, you should slowly move the torch to the future connection. When lumps form on the end of the wire, it is necessary to increase the wire feed speed into the apparatus.

How to set up a semi-automatic machine for high-quality gas supply?

Inverter front panel diagram

You can adjust the dosage of the amount of inert or carbon dioxide coming from a gas cylinder or reducer automatically or manually. With the correct settings of the semi-automatic welding machine, the electric arc will burn perfectly evenly. This allows the welding process to be carried out virtually without splashes.

It is necessary to ensure that the metal of the connection does not boil. This is achieved correct implementation settings of a semi-automatic welding machine by ear. The gas hisses quietly during welding, producing a uniform noise.

An experienced welder ensures that the gas is blown and not blown. In this case, the arc should not break, so you need to move the wire forward. If intermittent hissing sounds occur and the wire melts rapidly, which occurs faster than the burner moves, it is necessary to reduce the feed speed.

Sometimes it is necessary to adjust all the settings for high-quality welding for several days until an even, stable arc is obtained.

It has a stable sound and a characteristic crackling sound. The type and amount of gas supplied plays an important role in the process of regulating the welding machine. For example, a porous and weak weld will result from insufficient gas flow.

What semi-automatic devices allow you to make adjustments?

Image 1. Fundamental electrical diagram SPA.

The operation of any spa is associated with the presence of a welding transformer in its design. The susceptibility of welding current switches to wear requires the constant participation of a master regulating the welding process. For this purpose, you can use a contactless relay, which is the switching board of the transformer device. This is due to the presence of a significant resource in terms of switching.

The adjustment process is based on the use of an electrical signal transmitted through a circuit (IMAGE 1). The semi-automatic control system has an action logic that allows blocking the switching of each stage of the transformer device during a welding load. However, this can be a common reason associated with broken switches.

The simplest device that allows you to customize the SPA circuit is a throttle. It has several stages, which can be switched when the inductance level decreases or increases. Another possible device for adjusting the device is an active throttle.

Power supply circuit for a semi-automatic welding machine.

When using this device, you will not need to use mechanical switching, which will ensure smooth adjustment of inductance parameters. This adjustment mechanism allows you to correctly configure the process associated with the transfer of materials.

Arc welding manually, which allows connections to be made using a welding inverter, is also typical for semi-automatic machines. Therefore, an important PV parameter is provided for it. It is a percentage designation showing the permissible operating time of the semi-automatic device. This indicator will allow you to maintain the level of wear resistance of the equipment for a long time, ensuring its operation at a high-quality level.

Before using the semi-automatic device, the current value must be adjusted in such a way that the metal is not burned through. However, determining the exact current value is difficult. This point requires, before starting welding, to carry out training using a metal plate into which the wire is inserted. You can change the welding current using a rheostat. This is the most effective remedy, allowing you to adjust the welding arc for different metal thicknesses.

Recommendations for correctly setting up a semi-automatic welding machine

Semi-automatic welding process.

The welding current indicator should be set in the settings depending on the thickness of the metal being welded and the diameter of the wire used as an electrode. This dependence is relatively standard, so the value of the indicator does not fluctuate much.

Typically, the device body or its instructions should contain information about possible values welding current indicator. In certain cases, the table with indicators may be missing for some reason. Then experts recommend using the following current indicators for welding metal, taking into account its thickness, indicated in brackets:

1. 20 - 50 A (1-1.5 mm).
2. 25 - 100 A (2-3 mm).
3. 70 - 140 A (4-5 mm).
4. 100 - 190 A (6-8 mm).
5. 140-230 A (9-10 mm).
6. 170 - 280 A (11-15 mm).

Torch for semi-automatic consumable electrode welding: 1 - mouthpiece, 2 - replaceable tip, 3 - electrode wire, 4 - nozzle.

This list is associated with a fairly large range of indicators that are combined general trend. Its principle boils down to the fact that to weld the thickest material, a greater welding current is required. This indicator is determined by the diameter of the wire used.

If you use thin wire during the welding process, it allows you to configure the semi-automatic machine to operate using less current. If you use thicker welding wire, more current will be required. Due to the inertia of mechanics, the movement of the welding wire occurs slowly, gradually accelerating.

You can regulate the motor current using a special switch. The welding current must be sufficient to ensure complete braking of the wire. The current is adjusted in a semi-automatic welding machine using a trimming rheostat. Subsequent braking of the wire occurs after a certain time.

What results can you get from setting up a spa?

Submerged arc welding diagram.

As a result of the adjustments made, the welding wire should not spread or melt. This occurs when a very small current value is selected. You will need to increase the voltage to check the result. If the wire spreads well, then reverse side a “drop” should appear of the metal. This will mean that everything is normal.

If, after using the welding wire, a slight depression is formed, then the “drop” will hang on the other side. This is due to the choice of the welding current value above the norm. You should take another piece of metal to conduct the experiment at a lower voltage level.

If a hole appears instead of a wire, then this is due to the choice being too of great importance current You should use another workpiece to carry out semi-automatic welding at a lower voltage level. For training welding, workpieces coated with zinc cannot be used, since it evaporates and releases harmful substances. They can harm the human body.

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After preliminary training, you should finally make sure that the current settings are correct. In this case, the metal workpiece must be clamped with sufficient force. Only after this can you proceed to the main welding, not forgetting about safety precautions. Before welding, you should be dressed in a welder’s suit and protect your face with a special mask.