Arc Welding Equipment typically

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Welding Equipment

equipment used for arc welding typically consists of a constant current welding power supply and an electrode, with an electrode holder, a work clamp, and welding cables (also known as welding leads) connecting the two.

Arc Welding Equipment Power supply

A high output welding power supply for SMAW and GTAW

The power supply used in SMAW has constant current output, ensuring that the current (and thus the heat) remains relatively constant, even if the arc distance and voltage change.

This is important because most applications of SMAW are manual, requiring that an operator hold the torch.

Maintaining a suitably steady arc distance is difficult if a constant voltage power source is used instead, since it can cause dramatic heat variations and make welding more difficult.

However, because the current is not maintained absolutely constant, skilled welders performing complicated welds can vary the arc length to cause minor fluctuations in the current.

The polarity of the SMAW system depends primarily upon the electrode being used and the desired properties of the weld.

Direct current with a negatively charged electrode (DCEN) causes heat to build up on the electrode, increasing the electrode melting rate and decreasing the depth of the weld.

Reversing the polarity so that the electrode is positively charged and the workpiece negatively charged increases the weld penetration.

With alternating current, the polarity changes over 100 times per second, creating an even heat distribution and providing a balance between electrode melting rate and penetration.

Typically, the equipment used for SMAW consists of a step-down transformer and a rectifier, for converting alternating current into direct current.

Because the power normally supplied to the welding machine is high-voltage alternating current, the welding transformer is used to reduce the voltage and increase the current.

As a result, instead of 220 V at 50 A, for example, the power supplied by the transformer is around 17-45 V at currents up to 600 A.

A number of different types of transformers can be used to produce this effect, including multiple coil and inverter machines, with each using a different method to manipulate the welding current.

The multiple coil type adjusts the current by either varying the number of turns in the coil (in tap-type transformers) or by varying the distance between the primary and secondary coils (in movable coil or movable core transformers).

Inverters, which are smaller and thus more portable, use electronic components to change the current characteristics.

Generators and alternators are frequently used as portable welding power supplies, but because of lower efficiency and greater costs, they are less freqently used in industry.

Maintenance also tends to be more difficult, because of the complexities of using a combustion engine as a power source.

However, in one sense they are simpler: the use of a separate rectifier is unnecessary, because they can provide either AC or DC.

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