There is a very real opportunity to assemble a home-made welding machine from parts of old TVs. During Soviet times, many boys were fond of the radio business, not suspecting that knowledge acquired then can be very useful. A welding machine in the household farm is periodically necessary for almost everyone.
Scheme homemade welding machine.
However, even the cheapest factory-made model in the trade network costs a serious amount of money. Meanwhile, the old TVs that no one has been watching for a long time, but regret to throw it away, there is still a great deal left in their hands.
Choosing the right type of machine
First of all, it is necessary to decide on the apparatus to be assembled. Since the construction, which has a welding transformer, is heavy, has solid dimensions and requires a lot of copper wire, it is best to make a welding inverter with direct current. For him, just fit the electronic parts from the old TV. Such a device is easy to operate, is available for carrying by one person, consumes relatively little electricity and can work from an ordinary household outlet. Its main advantage is that it can weld thin sheet metal. The need for such work arises especially often for motorists who are engaged in repairing personal vehicles directly in the garage.
Electrical circuit simple monocate inverter.
The choice of the scheme of the future apparatus largely depends on the magnitude of the current that is planned to be obtained, and on the availability of specific details for its implementation. As a rule, such a welding machine is designed to operate with a current of 40 to 120 amperes. For the electronic circuit, the parts taken from several old TV sets of the Soviet assembly, both color and black-and-white, are quite suitable. Such a scheme is quite simple to perform at home and at the same time does not require additional installation after installation with the use of special expensive equipment.Back to table of contents
Selection of parts from old TVs
First of all, you need to find parts for the manufacture of the inverter. To do this, ferrite magnetic cores from horizontal transformers from old TVs are quite suitable. Three of them are added together, and the winding is wound on them, while the primary and secondary should be divided into two parts. They can be wound in fiberglass insulation, preferably copper. If you take aluminum wire, then its cross section should be somewhat larger. Since the primary thermal load will be the primary winding, it is necessary to leave gaps between the turns. The larger they are, the less overheating of the entire inverter will be and the whole apparatus will work better.
It is best to choose K78-2 from capacitors, they were met very often on TVs. Their working voltage is not less than 1000 V, and the dielectric losses are very small. Capacitors for low-frequency circuits, especially paper ones, should not be used, they will quickly fail.
Wiring diagram of the windings on the magnetic core.
Trinistors are best used with letter A in the labeling. You can also put B or G, but they will work worse. In this case, it is desirable to install several relatively low-power trinistors in parallel, rather than one powerful one, since during the operation of the device they will overheat and become easier to cool. They are soldered onto a metal plate, at least 3 mm thick, to facilitate the removal of excess heat.
Resistors for equalizing current in televisions are usually in a plastic shell. Since during the welding work they will also have a serious thermal load, the plastic must be removed before installation into the apparatus, otherwise it will quickly begin to melt and burn, emitting a stench and threatening the integrity of the entire structure. Diodes for assembling a diode bridge can be dialed with ease from multiple TVs. They need to be installed on the heat-removing plate as the trinistors, while one of them will have to be insulated from the steel plate with a gasket, preferably from mica. When attaching the diodes, as well as the trinistors, it will be necessary to use a special paste to remove heat. As a result, the diode welding rectifier will resemble a certain shelf, which is a separate structure. Between each pair of diodes should be an aluminum plate that removes heat.Back to table of contents
Manufacturing missing parts and assembly
In addition to parts from old TVs, some of the components used by the home-made device will have to be made independently. The choke can be made without the use of a framework of copper wire with a thickness of at least 4 mm, twisted into 11 turns.
The design of the welding rectifier.
Gaps of at least 1 mm in size must remain between the coils, because when the device is turned on and starts to work, the throttle will begin to overheat. To combat overheating, a cooling device is necessarily required. In this capacity, it is quite possible to install an ordinary household fan, which will provide air cooling, on a homemade unit. The throttle must fall into the stream of air coming from it, otherwise it will not be able to work for a long time without forced cooling.
Clamps for welding cables are best made from a bronze bolt M10, with the same nuts and washers. The bolt head presses a brass corner with a 3 mm side to the base, to one side of which a connecting wire is soldered inward. Welding cables on the device can be put KG16, since they are quite soft and flexible. The electrode holder can be provided with a power button. This is very convenient, because if you release it, the voltage of the electricity supplying the device is automatically turned off.
All parts and components of the resulting structure are mounted on a single textolite plate, the thickness of which should be about 5 mm. In the center of it you need to cut a round hole to install the fan. 4 racks with a section of 12 mm are fastened to the slab, on which the inner panel is placed.
It is necessary to drill holes in it for the switches that control the device and install a grill that protects the fan. The inner panel can be cut from both metal and PCB or other material. 6 racks are also installed on the outside, on which the welding cable and ground are wound compactly.
The assembled apparatus is placed in a rectangular case, which can be assembled from vinyl plastic, PCB or other similar material. In the side walls will need to drill holes for cooling ventilation. To their area was sufficient, they can be made in the form of automotive radiator grilles. It remains to put on the body a handle for carrying and fastening for a shoulder strap - and the self-made welding machine is ready for use.
So to make it, actively using details from old TVs, is not only possible, but also very profitable.