Abstract: The present application relates to a welding system comprising a main module provided with an outer casing identifying an input port for the connection to a source of external electrical power, an electric generator configured to adapt the electrical characteristics of said electrical power to a first type of welding, at least an output port for the connection to a welding torch, an electronic control unit configured to control the functionality of said electric generator. Said main module comprises a mechanical and electrical connection unit of a first type, said welding system comprising at least an auxiliary module provided with an outer casing identifying an electric generator configured to adapt the electrical characteristics of an electrical power to a second type of welding, at least a mechanical and electrical connection unit of a second type couplable to said mechanical and electrical connection unit of a first type.