Influence of air flow velocity distribution on current interruption in flat-type arc quenching chamber

Abstract Current interrupting capability and distribution of the airflow velocity were investigated in a flat-type air-blast arc quenching chamber. Seven orifice-nozzles with different inlet widths were used to obtain various distributions of the flow velocities. A number of interruption tests for an AC current with a peak value of 1000 A revealed that a decrease in the inlet width from 20 to 10 mm markedly raises the failure rate of the arc interruption from 40 to 97% and that raising the inlet width from 20 to 34 mm gradually increases the failure rate from 40 to 66%. Calculation results of airflow velocity distributions in the absence of the arc lead us to find out the correlation that less uniform distribution or wider generation region of the vortex increases the failure rate of the arc interruption.