Contactor device including arc supression means

An electrical contactor for connecting and disconnecting an alternating current power source and a load including

• a main relay having main contacts connected between the source of current and the load, first auxiliary contacts which close momentarily prior to and open shortly after the opening and closing of said main contacts, and second auxiliary contacts which open and close substantially simultaneously with said main contacts,
• solid state arc suppression circuit means responsive to the operation of said first auxiliary contacts and connected in parallel with said main contacts for providing a low impedance current path around said main contacts to suppress arcing,
• an auxiliary relay having contacts electrically connected in series with said arc suppression circuit means and operable in response to said second auxiliary contacts whereby said arc suppression circuit means is electrically isolated during initial closure of said main contacts, and
• delay circuit means connected to said auxiliary relay for delaying deenergization thereof to provide a current path through said arc suppression circuit means during the opening of said main relay contacts, the contacts of said auxiliary relay thereafter opening to isolate electrically said arc suppression circuit thereby to prevent inadvertent operation thereof and to prevent any leakage current from flowing therethrough.

A switching circuit for connecting and disconnecting an alternating current power source to a load including

• mechanically actuated electrical contacts for carrying current to a load on a continuous basis when closed,
• first and second series connected triacs electrically connected in parallel with said contacts,
• a third triac having its main terminals connected to the gate electrodes of said series connected triacs, and
• switch means electrically connected to the gate electrode of said third triac and
• means for actuating said switch means with said mechanically actuated contacts for providing gating current to said third triac immediately prior to and during opening and closing of said contacts whereby said third triac provides gating current to said series connected triacs to provide a low impedance current path around said contacts momentarily during opening and closing thereof thereby to suppress arcing.

A switching circuit for connecting and disconnecting an alternating current power source to a load including

• mechanically actuated electrical contacts for carrying current to a load on a continuous basis when closed,
• first and second series connected triacs electrically connected in parallel with said contacts,
• first and second switch means electrically connected to the respective gate electrodes of said first and second triacs, and
• means for actuating said first and second switch means with said mechanically actuated electrical contacts whereby said switch means close immediately prior to and during opening and closing of said contacts to provide gating current to energize said series connected triacs whereby a low impedance current path is provided in parallel with said contacts momentarily during opening and closing thereof thereby to suppress arcing.