Measured Propagation of Surges in the Winding of a Large A-C Motor

This paper presents the results of impulse tests performed at Ontario Hydro on a portion of a motor winding. The objective of these EPRI funded tests was to determine the wave propagation properties of the motor coils. In all cases, surge voltages were applied to a portion of the winding and the transient voltages, which appear at various points along the portion, were measured. Based on these measurements, conclusions are derived concerning the modes and speeds of surge propagation along the coils of the motor. The results should be of help to engineers and researches concerned with turn insulation strength and surge protection of large A-C motors. The presented data can be used as an aid in the development and calibration of wave propagation models needed for computation of electromagnetic transients in the windings of rotating machines.