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With this simple welding machine you can cut thin metals, weld copper wires, and engrave on a metal surface. Other applications can be found without problems. Such a mini welding machine can be powered with a voltage of 12-24 V.
Mini welding machine 12 V

The welding machine is based on a high-voltage high-frequency converter. Built on the principle of a blocking generator with deep transformer feedback. The generator generates short-term electrical pulses, repeated at relatively large intervals. The clock frequency is in the range of 10-100 kHz.
The transformation coefficient of this circuit will be 1 to 25. This means that if a voltage of 20 V is applied to the circuit, then the output should be of the order of 500 V. This is not entirely true. Since any pulsed transformer source or generator without load has powerful high-voltage pulses, reaching a voltage of 30000 V! Therefore, if you disassemble any pulsed Chinese charging, you will see a soldered resistor parallel to the output capacitor. This is a network load, without a resistor, the output capacitor will quickly leak out due to excess voltage, or worse it will explode.
Therefore, attention! The voltage at the transformer output is life threatening!

Scheme of a mini welding machine


Mini welding machine 12 V

Necessary Details:
  • The transformer is home-made, the manufacturing procedure is described below.
  • Resistors - power 0.5-2 watts.
  • The transistor was used by FP1016, but it is difficult to find because of its specificity. You can replace the transistor 2SB1587, KT825, KT837, KT835 or KT829 with a change in the polarity of the power source. Another transistor with a collector current of 7 A, a collector-emitter voltage of 150 V, and a large gain (compound transistor) is also suitable.

The transistor must be installed heat sink. Although this is not shown in the diagram, it would be nice to put a filtering capacitor parallel to the source so that all the interference from the operation of the blocking generator does not get into the source.
Mini welding machine 12 V

Transformer manufacturing


A transformer is wound on a piece of ferrite rod from a radio receiver.
  • Collector winding - 20 turns of 1 mm wire.
  • Base winding - 5 turns with a 0.5-1 mm occasion.
  • High-voltage winding - 500 turns with an excitation of 0.14-0.25 mm.

All windings are wound in one direction. First, the collector winding, on top of it the base winding. Then follows a three-layer insulation of white electrical tape. Next, we wind the high-voltage winding, 1 layer of 125 turns then insulation, then repeat. Total should be 4 layers, which is equal to 500 turns. From above, we also isolate with white tape in several layers.
Mini welding machine 12 V

Mini welding machine 12 V

Mini welding machine 12 V

Mini welding machine 12 V

Mini welding machine 12 V

Mini welding machine 12 V

Mini welding machine 12 V

Putting the circuit together. If everything is working properly, everything should start without problems. Since the operating frequency of the generator exceeds the sound frequency, you will not hear a squeak during operation, so do not touch the output of the transformer with your hands.
Mini welding machine 12 V

Start the generator with a voltage of 12 volts and increase if necessary.
The arc ignites from a distance of 1 cm, which indicates a voltage of 30 kV. High frequency does not allow a burning arc to burst, as a result of which the arc burns very stably.When using a copper electrode with close contact with another electrode, a plasma medium (copper plasma) is formed, as a result of which the temperature of arc welding-cutting increases.

Cutting and welding tests of the welding machine


We cut the razor blade with an arc.
Mini welding machine 12 V

We fuse copper wires up to 1 mm thick.
Mini welding machine 12 V

A thick copper wire was used as an electrode. It is clamped in a wooden match, since a dry tree is also a good insulator.
Mini welding machine 12 V

If you liked this small welding machine, then you can make it of both large sizes and power. But be extremely careful.
Also, to increase the power, you can assemble the generator using a push-pull circuit, and even with field-effect transistors, as here - Simple induction heater 12 V. In this case, the power will be decent.
Also, do not look at the bright discharges of the arc with an unaided eye, use special safety glasses.

Watch the video of the manufacture of the welding machine on the blocking generator



Video homemade author -
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Comments (8)
  1. Alexey
    #1 Alexey Guests November 22, 2017 19:10
    3
    With a 315th transistor. Why are you doing this like that?
  2. Alexander.
    #2 Alexander. Guests February 13, 2018 00:26
    0
    It's funny I'll come to work, spend a couple of hours (maybe more, it's just sitting at the computer) and check. From materials - everything is in stock. Even a couple of dead household radios. Even the notorious FP 1016 (I don’t remember where I got them from, but everything that’s not “field” doesn’t use it at all (as a “force”), although it doesn’t go to the basket (throwing out is easy :-).
    Actually - the ratio of turns. Well, no matter how it turns out. But I saw your video (do not believe your eyes). According to this - first check, then recall.
    Why is the power of 700 watts indicating the transistor ?! All retype? I’ll get a datasheet on it tomorrow - I haven’t found it today. But I’ll look for a blocking generator on a powerful fieldman (a cloud of them is also worthless).
    No, I won’t say anything. I'll try it first ...
    Why do I need it? Curiosity.
  3. Chem
    #3 Chem Guests April 20, 2018 16:12
    1
    Consumes a lot of idling.
  4. Arthur
    #4 Arthur Guests May 8, 2018 00:13
    0
    And which transformer is needed for the second option, the one that is more powerful on the field? Pliz, it is very necessary !!!
  5. Arthur
    #5 Arthur Guests May 8, 2018 10:02
    0
    Sorry for the inaccuracy! In a previous article, you said that this circuit is more powerful if you use it for microwelding. So the question is what transformer data should be?
  6. th
    #6 th Guests August 31, 2018 15:13
    0
    Assembled on 2SB1587. From 12V a little sparks, and from 24V the winding is smoky.
  7. Ilya
    #7 Ilya Guests 5 October 2018 01:07 AM
    1
    The proposed options for replacing the transistor are the full g .., 3 MHz frequency they have, and for the high-frequency arc the author of the video suggested 65 MHz - do you feel the difference?
    That is, the author of the article does not fumble at all in this matter and has not tried it himself.
  8. Guest Sergey
    #8 Guest Sergey Guests 23 january 2019 00:20
    0
    And as an option to use a switching power supply such as for halogen lamps? Only it is necessary to take at least 250W (I did not find more powerful in local stores) and rewind the winding a little. There, as a rule, the output contains 5-6 turns, the frequency is also decent, you can experiment ...

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