Zero Crossover Thyristor Firing Cards

These are very compact, sealed solid state cards with no moving parts, particularly suitable for high power switching of Capacitor Banks. Each Card can fire two separate Thyristor-Thyristor Module, with common control, without any need of external power source since the driver draws power from the mains 440Vac supply. Switching is silent, instant, does not cause any arcing and is unaffected by the number of switching operations, vibrations and corrosive atmosphere. The control input is optically isolated from the mains AC Power Switching Circuit. One Card is used per stage of APFC Control Panel. Input is a 3V-12VDC source in series with the APFC Controller Stage control output. A Single source can drive and control all the stages.