Testing of Electrical Machine Stator Coils Using Sharp-Fronted Impulse Voltage

This paper presents test results for assessing the impulse breakdown level of high voltage electrical machine stator coils, using a voltage surge with a risetime of the order of 0.1 μs. It was found that the difference between the voltage applied to the impulse generator before triggering and the peak voltage applied to the coil terminal changed dramatically and was a clear indication of breakdown.