Air-gap sparking-cause and cure

摘要

The results from the application of complex parameters derived by 3D finite element techniques to a circuit model representing the rotor of an induction machine, have demonstrated a full understanding of the phenomenon referred to as air-gap sparking. The results have been validated by observation and by extensive testing of full size high voltage motors. Fully insulated bars have been used to eliminate air-gap sparking and this insulation has been tested extensively during direct on-line starts.