WELDING WITHOUT CHARTS AND FORMULAS

Homemade welding machines are engaged not the first year. In their manufacture into account the advice and recommendations of the “Model construction” and other well-established technical publications and reference literature. Started with “Welding baby” (No. 11, ’87), using the Latr ready with the primary winding. For secondary — recommended magazine, Shino-wire not found. Dare to wind the desired number of turns of the flexible stranded wire 6 mm2 in vinyl insulation. And what? Of course, such a device quickly overheated even when welding of cellular electrode. To somehow solve the problem associated with cooling, have decided to omit the “svarochnik”… in the water. Came from the fact that the secondary winding is great for insulation. And primary, which went before the slider wasn’t exposed as proactively managed to cover it in several layers of protective varnish.

Camera fell in water-filled plastic bucket with a capacity of 20 l (metal is more dangerous) and give the output during the welding 140 A. However, with the use of 10-15 electrodes with a diameter of 3 mm, the coolant is heated to 60° C. so occasionally had to turn the machine off to the Bay again with cold water and “kerf” in the network, to continue welding.

 

The following devices I have had “dry” — is made on the basis of the stator of the electric motor. Saw: best to use the appropriate magnetic three-phase asynchronous machine with capacity of 4-5 kW. To release such a stator of the Cabinet shell is easiest with a hammer or heavy hammer, hitting the weakest spots.

 

Then removed the winding. And — in two steps. First clean it with any one side, using a hacksaw. Although it can be used for the same purpose hammer with a chisel, directing the impact force at a tangent to the diameter of the stator. Well and then, going from the opposite side, begin with a pair of pliers to pull the segments of the “half ragged outer” wires from the grooves. Released from the winding, the magnetic core will become toroidal core of the welding transformer.

As practice shows, if you select “pack iron” it is necessary for him to aspire to a size “a” of the stator, the comp would be in the range of 30…40 mm. Then to obtain the optimal cross section 20…25 cm2’ll have to divide our original Thor 2-3 pieces to size “in” was equal to 50…80 mm. Better to do it with a hacksaw, propilen outer molded ties in the slots (typically 8). Then, by removing the “damaged” 3…4 sheets “stator iron” clench ties, thereby bonding each of the future of toroidal cores. But the sharp arc-welding to get involved here does not follow, as occurs in these places eddy eddy currents lead to heating of the magnetic core and substantially reduce the efficiency of the transformer.

 

The internal teeth of the stator poles is selected by the chisel-kreytsmeyselem with special sharpening (see Fig.). Of course, we should not neglect the safety rules. It is necessary to use goggles and gloves. The chisel is best done with pliers, not your hands.

 

 

Welding transformer with magnetoroton from the burnt stator of the motor (insulation between windings, layers and the magnetic circuit conventionally not shown):

1 — leg-shock (from the bottles with household chemicals, rubber, 6 EA.), 2 — the wall of the casing (10-mm heat-resistant insulator sheet, 2 pieces) 3 — terminal-screed (bolt M8 copper or brass, 6 PCs.), 4 — nut M8 (copper or brass, 18 PCs), 5 — copper washer (28 PCs) 6 — power cable single core cross section 20 mm2 (2 PCs.), 7 — nut-lamb M8 (2 PCs.) 8 — branch (wire cut electric multi-strand section 20 mm2 in cotton insulation, 4-piece), 9 — magnetic core with a cross section of a Houston and s (from stator burnt motor), 10 — cable network two-wire, 11 is the output of the secondary winding of the transformer (2 PCs).

 

 

 

Sharpening chisels-kreytsmeyselya.

 

In any case not to cut the teeth Elektro or gas welding. Because the magnetic core in the transformer again will arise eddy currents. Therefore, it is best to use here, “the old-fashioned method” with a chisel and a hammer with a mass of 1 kg. And remaining after the cutting of teeth irregularities is advisable to remove the polishing using the abrasive wheel. The finished magnetic core-tor wrapped herringbone or other insulating tape on a fabric basis.

 

Now for the primary winding. The number of turns in it with an acceptable accuracy can be found by multiplying the value of voltage on the quotient of “40” on the cross-sectional area (in cm2) of the transformer core. In our case, the coefficient reflecting the estimated number of turns on 1 In equal to two.

 

Thus, for network (primary) winding is proposed “svarochnik” need only 440 turns. And is better to use copper wire 2…3 mm2 (with a diameter of 1.6…2 mm) glass cloth insulation. The layers of primary windings are carefully insulated from each other. As, however, and secondary layers, the number of turns in which, on the basis of the required voltage (56) and the above coefficient (2) must be equal to 112, and the cross-section is from 10 to 30 mm2. Winding wire can be taken from old electric motors with a phase rotor capacity 3…6 kW. For example, I used them wire with glass cloth insulation (cross-section 3 mm2) for the primary winding. By the way, these motors can borrow and busbar cross-section 18 mm2 for the secondary winding of the welding transformer. Especially as it comes from the purest of copper.

 

Of course, for winding “svarochnik” you can settle for the aluminum. But then the size of the cross section of each of the windings increases 1.65 times. For example, the primary wire will need to have at least 3.3 V…5 mm2. With this in mind, I’m in one embodiment, the welding transformer was forced to use a strong aluminum wire “noodles” with a cross section of 2×2,5 mm2 (the diameter of one core it is about 1.9 mm).

How to get the wire for that coil? To determine this, as they say, easy. By measuring the consumption of wire on 1 coil winding (see Fig.), should this value multiplied by the calculated number of windings. But to take (given the thickness of the insulation, etc.) with a three percent margin (for primary) or six percent (for secondary winding).

 

In his “svarochnykh” include a 5-speed adjustment (up to a maximum of 56), making the taps in the secondary winding, designed for a voltage 32, 38, 44 and 50 V. When switching to the coils, respectively, are 64, 76, 88 and 100. Taps prefer to perform by the winding mechanism cuts flexible wire with section of 10 mm2.

 

Find the exact location of the findings in the secondary winding is easiest experimentally by “trial and error”. Especially if its wrapped “loose”, and even conducted a flexible wire. Then feel free to include a transformer in the network, and conditionally accepting the first terminal of the secondary winding in General, pierce the insulation with needle probes in one or in another place. And finding thus the voltage At 32, 38, 44, 50 In, label them. If the secondary winding is wound busbar, it will still be limited to the “estimated” method. That is, to determine in advance which round will be performed one or the other branch, by multiplying the above ratio (2) by the required number of volts.

 

The finished transformer gives a convenient and reliable from the point of view of the users form. To do this, cut out two squares of 10 mm plywood. And even better — made of fiberglass or other heat-resistant insulator. In the middle of the drill a 30 mm round for ventilation (see Fig.), but symmetrically him and the corners — seven 8-mm holes for the passage of terminals-cable ties and power cord.

 

The case, in fact, ready. Well, the rest, I think, clear from the illustrations that are presented. I am convinced that to make yourself a good welding transformer according to the above method, anyone can.

 

In the proposed welding in the secondary winding of the findings in increments of 6 V. Using the principle of the autotransformer, it is possible to have at the output a whole “range” of voltages from 6 to 56 V. In particular, using insights 56 and 50, it is easy to obtain the differential voltage of 6 V. Conclusions In 44 and 56 To allow the output of 12 V. Connecting, for example, to such a transformer rectifier 200 And you can safely run the engine starter.

 

Yes, “svarochnik” really puts out up to 200 A in the secondary winding. This means that it is possible to use electrodes 0 2…5 mm! Being made on the proposed technology, the welding transformer has a small size (within 350x350x200 mm) and the true minimum weight (25 kg).

 

O. LAVROV, electrician