When building or repairing appliances or household appliances, quite often there is a need to weld any elements. To connect the parts, you will need to use a welding machine. Today it is easy to purchase a similar design, but you should know that you can make home-made welding machines.
The design of homemade welding machine.
Welding machines are direct and alternating current. The latter are used to weld on small currents billets of metal of small thickness. DC arc welding is more stable, it is possible to perform welding on the forward and reverse polarity. In this case, you can use the electrode wire without coating or electrodes. In order to give the durability of the arc, at low currents it is recommended to do an overvoltage of no-load winding welding.
In order to rectify alternating current, ordinary bridge rectifiers on large semiconductors with cooling radiators should be used. In order to smooth out the voltage ripple, one of the terminals must be connected to the electrode holder via a special choke, which is a coil of several tens of turns of the tire made of copper with a cross section of 35 mm. Such a tire can be wound on any core, it is best to use a core from a magnetic starter.
The electrical circuit of the power unit of the welding machine.
In order to rectify and smoothly adjust the welding current, more complex circuits should be used using large thyristors for control.
The advantages of constant current regulators include their versatility. They have a large range of voltage configurations, and therefore such elements can be used not only to gradually adjust the current, but also to charge the batteries of batteries, to power the electrical elements for heating and other chains.
AC welding machines can be used to connect workpieces with electrodes whose diameter is more than 1.6 mm. The thickness of the joined workpieces can be more than 1.5 mm. In this case, there is a large welding current, and the arc glows steadily. Electrodes which are made for welding exclusively on alternating current can be used.
Steady arc burning can be obtained if the welding device has a falling external characteristic that determines the relationship between the current and voltage in the welding chain.
What should be considered in the process of manufacturing welding machines?
Welding transformer on the basis of the widespread LATR2.
For a stepped overlap of the spectrum of welding currents, it is necessary to switch both the primary windings and the secondary windings. For a smooth current configuration within the selected spectrum, the mechanical properties of the movement of the windings should be used. If you remove the welding winding in relation to the network, the magnetic flux dispersion will increase. It should be understood that this may lead to a decrease in welding current. In the process of making a home-made design for welding, it is not necessary to strive for complete overlapping of the spectrum of welding currents. It is recommended first to assemble a welding machine with your own hands for working with electrodes of 2-4 mm. If it is necessary to work on small welding currents in the future, the design can be supplemented with a separate rectifying device with gradual adjustment of the welding current.
Self-made designs must meet certain requirements, the main of which are the following:
- Comparative compactness and low weight. Such parameters can be reduced by reducing the power of the structure.
- Sufficient operation time from the 220 V electrical network. It can be increased by using steel with high magnetic permeability of heat-resistant insulation of wires for winding.
Such requirements can be easily met if you know the basics of the construction of welding structures and adhere to the technology of their manufacture.Back to table of contents
How to choose the type of core for the fabricated design?
The electrical circuit of the bridge rectifier welding machine.
In the process of making such structures, rod magnetic wires are used, they are more technological. The core is assembled from electrical steel plates of any configuration, the material thickness should be 0.35-0.55 mm. Elements need to pull the studs, which are covered with insulating material.
In the process of selecting the core should take into account the size of the "window". Winding elements should be placed in the construction. It is not recommended to use cores with a cross section of 25-35 mm, since in this case the fabricated structure will not have the necessary power supply, as a result of which it will be rather difficult to produce high-quality welding. In this case, the device cannot be overheated either. The core should be 45-55 mm.
In some cases, welding structures with toroidal cores are produced. These devices have higher electrical performance and low electrical losses. It is much more difficult to make such devices, since the windings will need to be placed on the torus. You should know that the winding in this case is quite difficult to perform.
The cores are made of ribbon transformer iron, which is rolled into a roll in the shape of a torus.
To increase the internal diameter of the torus, on the inner side it is necessary to wind off a part of the metal tape, then wind it onto the outer side of the core.Back to table of contents
How to choose the right winding design?
Wire winding scheme.
For the primary winding it is recommended to use a wire made of copper, which is covered with insulating material made of fiberglass. You can also use wires that are covered in rubber. It is not allowed to use cords that are covered with PVC insulation.
A large number of network winding taps are not recommended. By reducing the number of turns of the primary winding, the power of the welding apparatus will increase. This will lead to an increase in the arc burning voltage and a deterioration in the quality of the connection of the blanks. By changing the number of turns of the primary winding to achieve overlap of the spectrum of welding currents without deterioration of the welding properties will not work. To do this, it will be necessary to provide for switching the turns of the welding secondary winding.
The secondary winding should contain 67-70 turns of the tire made of copper with a section of 35 mm. You can use a multicore power cord or flexible stranded cord. Insulating material must be heat resistant and reliable.Back to table of contents
The self-made device for welding from the autotransformer
The scheme of the inverter welding machine.
The welding device operates from the 220 V electrical network. The design has excellent electrical performance. Thanks to the use of a new form of magnetic wire, the weight of the device is about 9 kg with dimensions of 150x125 mm. This is achieved by using tape iron, which is rolled into a roll in the shape of a torus. In most cases, a standard package of W-shaped plates is used. Electrotechnical indicators of transformer construction on a magnetic wire is about 5 times higher than that of similar plates. Electric losses will be minimal.
Elements that will be needed in order to make a welding machine with your own hands:
- magnetic wire;
- electric or lacquer fabric;
- wooden rail;
- insulation material;
The process of manufacturing a welding device of this type
Assembly scheme of the welding machine transformer.
In order to get rid of the search for rare iron, you can buy a ready-made 9 A autotransformer or use a magnetic wire from a faulty laboratory transformer device. To do this, remove the barrier, the armature, and then remove the damaged winding. The released magnetic wire will need to be isolated from the layers of the winding by an electrical card or several layers of lacquer fabric.
Welding transformer device has several windings. In the primary, a PEV-2 wire with a cross-section of 1.2 mm and a length of 170 m is used. To make it easier to work, you can use a shuttle (wooden lath 50x50 mm with slots at the ends). The first thing you need to do is to wind the entire wire. Between the windings it will be necessary to place a layer of insulating material. The secondary winding is performed using copper wire in cotton or vitreous insulation. In this case, it will be necessary to make 45 turns over the primary winding. On the inner side of the cord is placed the coil to the coil, and on the outer side you will need to leave a small gap. The gap is needed to ensure that the wire is evenly distributed and well-cooled.
Block diagram of the welding inverter.
A few people need to make a design. One person should carefully, without touching the near turns, stretch and install the wire. A partner must hold the free end of the cord, excluding its twisting. If you touch the near coils, the insulation may be damaged. A welding transformer that is manufactured in a similar way will be able to produce a current of 50-185 A.
If there is already an autotransformer available at 9 A, then it should be examined. If it turns out that the winding is not damaged, it will greatly simplify the case. If you use the finished winding as the primary, then you can make a transformer structure in 1 hour, which gives a current of 70-150 A. To do this, you need to dismantle the fence, current collector switch and fittings for fasteners. It will be necessary to identify and mark the 220 V leads with a marker. Other ends need to be carefully isolated, and then pressed against the magnetic wire for a while. This is done so that these elements are not damaged when working with the secondary winding. Installation of the latter is the same as in the previous version, but in this case it will be necessary to use copper wire of the same cross section and length.
Manufactured transformer device will need to be placed on a platform with insulation in a special casing. You must first make holes in the casing for ventilation. The wires of the primary winding should be connected to the mains 220 V cable. In the chain it will be necessary to provide a circuit breaker for shutdown.
The terminals of the secondary winding should be connected to the flexible wires covered with insulating material. To any of the cords will need to attach the holder of the electrodes, and the second - welded workpiece. This cord must be grounded for user safety.Back to table of contents
Nuances to know
Current adjustment can be provided by phasing in the cord string of the electrode holder - wire from nichrome with a diameter of 3 mm and a length of 5 m. It should be rolled up with a snake, which is attached to a sheet of asbestos cement. Connect all the wires you need with M10 bolts. By picking, moving the wire connection point along the snake, you will need to set the required current. It is possible to use the option of adjusting the current using electrodes of different diameters. For welding, use electrodes with a diameter of 1-3 mm.
All the necessary materials for transformer construction can be bought in building supermarkets. A person who is familiar with electrical engineering, to make such a device with his own hands is quite simple.
To eliminate burns during the work, you will need to use a protective shield made of fiber, which is supplied with a light filter.
Must be the following elements: a headdress, protective clothing and gloves. The welding machine must be protected from moisture and prevent overheating.
Making a welding machine with your own hands is easy if you know the manufacturing technology.