Break arc behaviors of Ag and AgSnO2 contact pairs under different contact opening speeds in DC load circuits

In a DC inductive load circuit (L=20mH) with a power supply voltage of DC14V, break operations of a load current in the range from about 0.8 to 4.8 A were conducted with Ag contact pairs and AgSnO2 contact pairs at contact opening speeds in the range from 0.5 mm/s to 20 mm/s. For the break operations by the AgSnO2 contact pairs, the average break arc durations at current levels over 2A became shorter by increasing contact opening speeds, while no significant influences were recognizable at smaller current levels. For the break operations by the Ag contact pairs, similar tendencies were found at 4.8A operations, but in a less drastic manner. Moreover, with the break operations in a resistive load circuit, more complicated tendencies were observed.