An alternative to DC test equipment for performing off-line diagnostic testing on large rotating machines

In recent years conventional DC testing of installed insulation has begun to lose favor. The authors present a novel technique that overcomes all previous objections to DC testing and many of the disadvantages, such as size and weight, of the already identified alternatives. The power supply, called a pulsed resonant power supply, produces line frequency output with no DC content. There is no switching involved; hence the supply is readily adaptable for partial discharge and power factor measurements. With its many attributes, the pulsed resonant power supply is well suited for maintenance testing of large rotating machines