Test results are compared for impulse-breakdown level of the turn insulation in electrical machine coils, with and without grounded metallic sheath, using a voltage surge with a risetime of the order of 0. 2 mu s. It is found that the breakdown of the machine coil in the sheathed condition is indicated by a large drop in the first peak voltage, along with a complete change in the voltage waveform.
|Number of pages||5|
|Journal||IEEE Transactions on Electrical Insulation|
|Publication status||Published - Aug 1986|