Current Interruption Ability of Vaccum Switches

The ac current interruption ability of a vacuum switch has been examined and found to be a function of parameters which pertain to the electrodes contained in the switch and to the circuit to which the switch is connected. The dielectric recovery data for switched-off vacuum arcs are converted into a form that is applicable for determining the theoretical current interruption limit. Generalized plots of theoretical al current interruption limit versus the reciprocal of the RRRV of the circuit are given for switches having butt-type Cu or Ag electrodes. The current interruption limit of two different sizes of vacuum switches is calculated and checked against experimental test results.