An engine driven welding system includes two power generators, each having a rotor and a stator. Each rotor is mounted on a respective drive shaft, with one of the drive shafts being driven by the engine and the other drive shaft being releasably coupled to the engine driven drive shaft. This provides a modular type construction of the welding system, in that the outboard power generator can be selected or changed as needed for a particular application. The coupled drive shafts are supported by two bearing assemblies. Also disclosed as additional features for any welding system power supply is a removable plate having one or more connectors releasably attached thereto for facilitating installation of an electrical component for a welding system power supply; and also a power switch having a member that restricts rotational movement of the switch.