The interruption of vacuum arcs at high DC voltages

In 1967, it was observed by the authors that an axial magnetic field applied to a vacuum-arc discharge in a coaxial diode was capable of extinguishing the discharge. A continuing effort to develop a high-voltage dc arc interrupter has resulted in a simple, lightweight device capable of interrupting 800 A at 25 kV. Operation at higher levels was limited, not by the interrupter, but by the lack of availability of adequate power supplies. This device has been operated at repetition frequencies of several pulses per second. Successful operation at a frequency of 1 kHz has been achieved at lower power levels. The turn-on and turn-off times are, respectively, as short as one and two microseconds, The pulsewidth is continuously variable from a few microseconds to infinity (dc operation). It has been demonstrated that operation above 10 kV requires very pure materials and the use of ultra-high vacuum techniques. Among the many uses for the interrupter are those in high-power modulators and high-power inverters. An enticing future application is for switching in high-voltage dc power transmission systems.