Electric welding power gen sets

Welding power sets may be of different types and they can be selected depending upon the nature of available power supply (either DC or 1-φ AC). Now and then diesel driven engine may be used under the absence of power supply, initial and running costs, the location of operation, necessary output and the type of work, and based on the available floor space.

A DC generator is driven by a prime mover (electric motor or diesel engine) which produces DC current in either or reversed polarity. The current complete by DC generator is alternating that can be converted to direct quantity by the use of a commutator. The differential complex DC generator is used as a welding generator. Since it has drooping volt–amp characteristics. As the load current increases, the net flux due to the series and the shunt fields in resistance decrease and hence the generated EMF also decreases.

In the past and indeed up to quite recently, film studios often generated their own power. This was in the form of a d.c. voltage, usually at 120 V and mainly used because of the need to supply carbon arc sources used in the film industry. The basis of the 120 V was the importation from America of the lighting technology used in film studios. As the public supply authorities did not in general, supply d.c. voltage, it was necessary for the film studio to install large diesel driven generators. Associated with the 120 V systems used was the need to have much larger copper feeder cables than would be normal in the UK, due to the current being used. With the advent of much more sophisticated d.c. power supplies, particularly of a size such as the film industry would demand, it was easier to supply systems with a.c. voltage and transform and rectify it to the 120V needed.