DC Vacuum Arc Voltage Characteristics Subjected to an External Transverse Rotating Magnetic Field

A well-known method of low voltage DC current interruption is to increase the arc voltage to exceed the electric source voltage. The objective of this paper is to experimentally determine DC vacuum arc voltage characteristics subjected to an external applied transverse rotating magnetic field. In the experiments, the DC arc current was in a range from 100A to 200A. A Transverse rotating magnetic field was generated by two pairs of crossed placed coils, and the phase angles of the alternating currents driving the two pairs of coils were shifted by 90 degrees. The transverse magnetic flux density was in a range from 0-15mT by adjusting the currents in the coils. The frequency of the rotating transverse magnetic field was set as 800 Hz. The experimental results show that the DC vacuum arc voltage increased over a hundred Volts with applying the transverse rotating magnetic field in the first two runs of the tests. But the arc voltage did not increase in further tests, in which it increased only by 5-10V.