Influence of throat area on the resistance spot welding process

The paper describes an experimental study made in order to establish how the welding-cable length in resistance spot welding affects welding parameters and the welding process itself. A common alternating-current welding device for welding with a current frequency of 50 Hz was used to investigate optimum welding parameters with welding cables of different length and with workpieces of different materials. It was found that longer welding cables produce increases in ohmic resistance and inductive resistance. Higher ohmic resistance produces thermal losses and a lower welding current in the secondary circuit. Inductive resistance, however, produces reactance in the secondary circuit of the welding transformer, which means a loss as far as resistance welding is concerned.