I need to determined when a Thyristor has been damage by an Overvoltage or by an Overcurrent. Several of our Thyristor SKKT 273 / 18E has burned also the pulse card. Any other element result damage.
Might not be the thyristor. The gate is normally driven with a pulse transformer to isolate the high-voltage thyristor from the low-voltage pulse electronics. These insulation between the windings on these transformers can fail. This allows high-voltage to get to the driver electronics causing damage.