Relay contacts of multi-electrodes with timely controlled operation for arc discharge suppression

We propose a new electric contact device for stable arc discharge suppression. The functions of conventional electric contacts are categorized into the energizing contacts and the switching contacts. A capacitor is connected in series to switching contacts. Arc discharge suppression was experimentally measured and theoretically analyzed using equivalent circuits. The V-I characteristics of breaking contacts were introduced with a time dependent resistor R(t) into the circuit. The transient responses at contact were numerically derived by SPICE, and compared to the minimum discharge current and the minimum discharge voltage, clarifying the function of the parallel capacitor for stable arc discharge suppression. Using two conventional relay contacts, no stable arc break operation was confirmed for a 42 V/3 A. For the reliability examination, contact resistances were measured over many breaking operations, and the contact surfaces were observed.