Transformer Type Power Sources

These are the simplest and cheapest type available for arc welding. These are the mainly used for SMAW, AC SAW and gouging applications. These are mostly designed to give a drooping characteristic output. Some manufacturers give OCV selection for transformers by providing tap changing at the primary.The control of current for welding in these type of power sources is done by anyone of the following method.

•  Moving coil
•  Moving core shunt
•  Variable choke at the output
•  Saturable reactor control at the output

Out of these, the most commonly used type is the moving core shunt. In all these types the power factor and hence the efficiency of power source is not good. When there are many transformer type power sources connected in a shop, the load should be more or less balanced for providing balanced loading. In some cases power factor correction capacitors are integrated along with each transformer. Modern welding shops are not using such power sources.