Hi we have just changed the thyristor CMA30E1600PN TO CMA30E1600PB to improve thermal performance of the solid state relays. Using 3mil aluminium plate heat sink. After the change we experiencing bursting of middle thyristors i.e. thyristors related to phase b that too thyristors which is connected to the input side. the image are as follows. could you please explain there is a increase in junction capacitance of between the two thyristors whether this could be the cause.
There were burnt marks left with heat sink and place where the thyristors are screwed to mount on the heat sink. Only the middle thyristor.
