What is the purpose of a welding transformer ?

Question

Has to do with Shielded Metal Arc Welding.

Answer 1

Heat is produced more efficiently at very high current.
Power = current-squared * resistance.

The resistance of the metal being welded is very very low (sometimes a fraction of 1 Ohm). It is very difficult to apply a high voltage to a short-circuit (fraction of 1 Ohm), but it is very easy to apply high current to a short-circuit.

The welding transformer converts the line voltage at normal current to a low voltage at very high current, for welding.

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Answer 2

Great answer by TLBS101.

The welding transformer also has many tap positions to allow the user to adjust the output voltage in 1-2 volt increments. Typical welding voltages across the pieces of metal are in the range of 6 V to 36 V. The selected voltage depends on the thickness and type of metals being joined. Using too high a voltage will burn a hole right through the metal.

The windings inside a welding transformers have also been specially designed to handle the repetitive current surges.

Answer 3

Transformer Purpose

Answer 4

Note also that welding power supplies that contain rectifiers to provide direct current (DC) for DC welding are sometimes referred to as "transformers" even though they contain both a transformer and a rectifier and are more properly called "power supplies."