Tests on Lightning Protection for A-C Rotating Machines

Supplementing theoretical studies on the protection of a-c rotating machines against impulse waves and previous tests on individual protective devices, a comprehensive series of tests on over-all protective schemes has been made. As a result, definite conclusions are drawn regarding the proper lightning protection for machines connected directly to overhead lines or connected through transformers, giving consideration to the type of transformer connection. Considerable information also is obtained on the propagation of surges through windings, and on the surge impedances of machine windings.