MMA welding with coated electrode

The mentioned bellow equipment is used for manual welding with coated electrodes.

 

Welding transformer for welding with coated electrodes are working on AC (alternative current). A welding current is adjusted with:

Choke with the same core; Separate choke; Movable winding; Movable magnetic shunt.

It is required for starting and maintaining an arc between electrodes and materials that rectifiers have a falling static characteristics. Voltage on a non-load state usually amounts to 60 - 80V. There is also "hobby" equipment with voltage of 45V available on the market. It should be used with low-voltage electrodes, e.g. 6012 (MOST). Application of rectifiers is limited because many electrodes require DC.

 

Welding generators consist of two parts: engine and generator. Electric motor + dynamo = welding motor-generator; internal combustion engine + dynamo = welding generator. This kind of equipment is rarely used because of its heavy weight, large dimensions and high energy consumption.

 

Rectifier welding set transforms AC (alternative current) into DC (direct current) that provides required characteristics and welding current. Welding rectifiers are supplied from transformers with movable shunts of magnetic stream. Unfortunately, shunt's drive is complicated and rectifiers do not offer remote control of a welding current. These disadvantages can be avoided if energy-electronic components, such as thyristors and transistors, are used. Both static and dynamic characteristics, as well as welding energy can be controlled dependently on a chosen welding program in thyristor rectifiers.

 

Welding inverters (rectifiers with internal transformation of frequency). Thanks to high-power thyristors, which were used in high-voltage inverters, frequencies of a few dozen of kHz above acoustic band were achieved. Since transformation of frequency was introduced, power sources for arc-welding are lighter and characteristics of a zone between electrode and welded material (especially transition of a metal) can be controlled.