Welding Power Supply Characteristics

The welding power sources with constant voltage volt ampere characteristics are infact used only for continu ous electrode wire welding such as gas metal arc welding.

Welding power supply characteristics. They can use either direct current dc or alternating current ac and consumable or non consumable electrodes the welding region is sometimes protected by some type of inert or semi inert gas known as a shielding gas and filler. Plug in power mig welding power supplies are the most common and only work if you have the electricity needed to run the welder. If the voltage of a welding arc at varying arc lengths is plotted against the welding current the curves illustrated in fig. Such a machine is designed specifically for gas shielded metal arc welding and is not generally suitable for stick electrode welding.

These processes use a welding power supply to create and maintain an electric arc between an electrode and the base material to melt metals at the welding point. Multi process mig welding power supplies come in two forms. They supply the power needed to weld but not the wire feeder or anything other welding equipment needed. The dip transfer characteristics depend entirely on the dynamic characteristics of the power source.

Constant voltage power supply the other basic type of arc welding power supply produces a constant voltage. A welding power supply is a device that provides or modulates an electric current to perform arc welding. The primary functions of the power source are to produce sufficient heat to melt the joint and to generate a stable arc and metal transfer. There are multiple arc welding processes in common use ranging from relatively simple shielded metal arc welding smaw to more complicated welding processes using inert shielding gas like gas metal arc welding gmaw or gas tungsten arc welding gtaw.

It has a slightly downward or negative slope because of sufficient internal electrical resistance and inductance in the welding circuit to cause a minor droop in the output volt ampere characteristics. The low current are used to give a quick freezing lead suitable for all positional welding and is ideal for thin sheet metal welding. Thus at any voltage setting current may vary from zero to an extremely high short circuit current. With constant voltage power supply the arc voltage is established by setting the output voltage on the source.

In order to understand how the requirements of the processes affect the design of the power source it is necessary to understand the interaction of the power source and the arc characteristics.