What do I need to know before work?
Before making a welding transformer, it is necessary to understand what it is and what characteristics it has. It is the main element of almost any electric welding machine, the converter of the energy of the network electric current into the welding current, which serves as a power source. The weight of the device itself and the range of its technical capabilities will depend on the transformer.
The main technical characteristics of the transformer for the welding machine: rated voltage, rated frequency, power consumption, welding current range, idling voltage. When assembling a self-made welding transformer, you should consider all these characteristics.
How to make your own welding transformer?
As a matter of fact, the transformer is two coils of a copper wire which is wound on an iron core, therefore to begin manufacture of the welding transformer follows from windings. It consists of two coils having a different number of turns. Two coils are wound on each coil - primary and secondary.
Primary is connected to the current source, and in the secondary winding, due to induction, there is a current of lower voltage, but a larger amperage. The winding of the welding transformer has its own peculiarities: it is always produced in one direction, each layer of the winding is insulated with a layer of electrocardboard, tracing paper or cotton insulation.
Before winding the welding transformer, the wire for the windings should be selected correctly. For the primary winding, a copper wire in glass-cloth insulation is suitable. Do not use wires in PVC winding, as it can melt, and this will lead to a short circuit.
If the transformer is very humid, then there are not enough coils of the network winding and it is necessary to add a certain amount. The secondary winding must be wound on both sides of the core. A wire with a cross section of 20-25 mm2 can be used. When using an aluminum cable, you should increase its cross section by 1.5 times.
Number of turns of windings have to be selected for the wire of the available section, thus obtaining the necessary power. Primary windings should be connected in parallel, and secondary - in series.
Features of homemade
devices The homemade welding DC transformer features soft arc ignition, the ability to weld sheet metal, and the absence of non-weldable areas. The principal difference from AC transformers is the overestimated voltage in the secondary winding.
This is achieved by introducing a diode bridge with a capacitor into the secondary circuit, resulting in an output voltage of 1.5 times.
A three-phase transformer can be manufactured using a three-phase step-down transformer of 380 V, with a power consumption of 2 kW.Such an aggregate is used to power an electric tool or lighting with a lower voltage. A transformer with one burnt coil will do.
A homemade transformer for a semi-automatic welding machine must be powerful enough. It is necessary that the primary winding consists of 220 turns of a copper cable with glass-fiber insulation with a diameter of 2 mm, and a secondary winding consisting of 56 turns of a copper wire of 60 mm2 cross section.