WELDING YOUR

Almost a quarter of a century are a subscriber of the journal “modelist-Konstruktor”. About the same age are engaged in electric welding apparatus (ESA). Convinced that the most appropriate mass and power “svarochnik” – with a toroidal magnetic core (for example, from a burnt-out electric motor power 3-5 kW). Manufacturing technology of such devices has been maintained in the pages of “Modeller-designer” (see, in particular, publication in № 8’92, 11’92, 3’94, 9’94, 1 ’96, 3’96, 8’97, 11’99). From my own experience and practice of other handmade designers, I also believe it is appropriate to emphasize that the idle current from sturdy welding transformer designed for connection to a household 220-volt network should be of the order of 0.5-1 A. If a smaller value of this parameter decreases the power at most – heated magnetic core, and with it the whole of ESA.

I must also note: if the connection “svarochnik” is planned to the network with a voltage of 220-380 V, on top of the primary winding is highly desirable to have additional, 160 volt (the required number of turns specified by the voltmeter), followed by a secondary, welding.

In a case of this homemade ESA can be performed, for example, from perforated metal sheet with thickness 1 — 1,5 mm. At the base it is mounted on insulating supports himself toroidal transformer, fixed top clamping plate-insulator with double threaded rod M10. Perforations with a diameter of 20 mm to create a natural ventilation necessary for our “svarochnik”.

To the base is fixed (e.g. screws and brackets-parts) facing: also of sheet metal, but with a “Welt” perforations. The distance between the walls and transformer should be, as practice shows, not less than 30 mm — again to facilitate air cooling.

The top case will westchest scarves, which are attached to the staples pen. The basis of each of these pens is a pipe 20×2 mm with side holes with a diameter of 10.3 mm at the ends, which are inserted M10 studs and are welded through the front window.

Homemade “svarochnik”:

1 — support-absorber (4 PCs); 2 — bracket-stud with two M10 washers and a couple nuts (4 sets); 3 — trim with eyelets for ventilation; 4— pin M8 with two washers and two nuts (2 sets.); 5 — base with ventilation holes; 6 — insulating lining (textolite, Micarta, or a wooden plank for 10-15 s, 4 items); 7 — magnetic (motor power 3-5 kW); 8 — insulating substrate (glass 2-3 layers); 9 — network primary winding (220-380 V, the idling current of 0.5—1 A); 10 — additional coil, 160; 11 — welding secondary winding; 12 — protective casing of the welding transformer (fiberglass, 2-3 layers); 13 — solitaire (4 pieces); 14 — carrying handle (metal tube 20×3,2) 15 — clamping strip (textolite, Micarta or wood dochechka 10-15 s); 16 — terminal bar (15-mm glass fiber or other heat-resistant insulator); 17 — the light (thyratron MTX-90 60-kiliany MLT-0,25 or “neonka” TN-02 series-connected resistor of about 120 kω); 18 — terminal 220 (2): 19 — welding terminal (M10 bolt with two nuts, two washers and nut “lamb”, brass or copper, 2 sets.); 20 — “end” welding the windings (copper NLI brass, sheet 1,5 s, 2);
material children. POS. 3.5 and 13 is a metal sheet s1 to 1.5; the type and number of fasteners for the cladding and the terminal bar is not shown

In the final stages of Assembly established the panel of 10 mm of fiberglass (or some other equally heat-resistant insulator)located on the network and more powerful welding terminals, and the operation indicator lamp On. As the latter can be used thyratron MTX-90 60-kiliany resistor or “neonka” MNZ (T-0.2) is series-connected with the MLT-0,25 impedance of 120 ohms.

For adjusting the current during welding it is recommended to use a homemade rheostat. Base — 100 mm cut asbestos-cement pipe with a diameter of 200-250 mm. as used resistant coil spring (chrome vanadium steel wire with a diameter of 3-4 mm, wrapped on a cylindrical billet, 40 mm in diameter) from the drill.

The end of the coil-workpiece is heated red hot, are ignored in the drilled holes inside the asbestos-cement pipe-base and the pliers bend the bolt M8. The beginning of the resulting resistant winding connected to the welding 1-m cable with the help of makeshift terminals, consisting of a M8 bolt, nut and two washers. Well, the adjustable current collector is carried out with a copper knife-regulator is inserted between the spring windings of the rheostat.

Of course, it is useful to equip the ENA and sufficiently powerful straightener that will enable you to perform high-quality welding on direct current. As practice shows, are the most acceptable technical solution, based on the so-called the bridge rectifier diodes are capable of giving to the load a direct current of not less than 100 A. for the purpose of cooling each of semiconductor valves it is desirable to provide a radiator having a heat transfer area of about 200 cm2.

Pretty good performance, for example, the rectifier bridge, composed of two groups of powerful bipolar diodes B200 and ВЛ200, the design of which (with the “anodic” or, conversely, the “cathode” heat removal and having a distinctive corps, respectively, green or crimson) makes it easy to combine them in a super compact unit with “plus-minus” and “minus-plus” contact-radiator groups, between which is installed a rubber gasket (see “modelist-Konstruktor” No. 5’97 and No. 9’02).

For reliable ignition of the arc is usually used a capacitor or inductor. However, the latter is preferable because its inherent high energiekosten and performance. The construction depends on the magnetic circuit. The most affordable for many is the “iron” of the burnt transformers. More precisely, packets of typical configurations from electrical steel.

Ring rheostat:

1 — base-insulator (asbestos cement pipe); 2 — resistant coil (cylindrical coil spring from drills, chrome vanadium steel wire d3 — 4 wrapped d40, the ends are annealed and after installation at site bent bolt M8); 3 — terminal (M8 bolt with nut and two washers, 2 sets.); 4 — welding cable “limit switch”; 5 — carrying handle (steel strip 40×2); 6 — welding cable with two “limit switches”; 7 — swage-insulator (rubber hose 20×3, L50); 8 — blade contact (copper strip 25×5, L110)
 

Scheme rectifier-grossartige unit, as well as options of the welding choke in the core magnetodiode (a) and on armor (b), sostavleniia of the two model cores core:

1 — magnetic (package, typed in the NC the most affordable plates of transformer steel); 2 — insulating gasket (2-3 layers salonsalon tape); 3 — winding (35 to 40 turns of cable with a total secheniem 25 mm2 copper wires or aluminum 35-40 mm²); 4 — clamping bracket (metal area of 15×15 or 25×25,4 pieces); 5 — coupling (stud with two nuts and washers, 4 or 8 set).

Good chokes work, in particular, when the magnetic core to them — rod core with a width of 30 mm and a thickness of 150-250 mm package (from the old power supply) or two coupled, adapted as a kind of armor with a package thickness of 100-150 mm. Winding contains from 35 to 40 turns of well insulated wire (conductive bus, cable) section 35-40 (aluminum) or 25 (copper) mm². Advantage: you can use any electrode.

These chokes easily incorporated into the rectifier, or arranged in separate blocks. If you have to deal with welding many besides use the 4-mm electrodes, we can not do without forced air cooling. In this case, the fan is preferably set directly on the rectifier ESA.

In the last author’s version had to go to the installation of more powerful radiators from 500-amp diodes. The result is a homemade ESA, which according to its technical and operational parameters capable of being, that is, on equal footing with welding machines of industrial manufacture.

A. PEVNEV, Dimitrovgrad, Ulyanovsk region.