Study of a High-Power Rotary Arc Gap Switch

Switch is one of the key issues in the pulsed power generation and applications. The closing switch is an essential part in capacitor-based energy-storage systems, and the spark-gap switches are a popular choice. These switches have very limited lifetime due to electrode erosion resulting from localized arc heating in high current. To extend the switch lifetime by minimizing electrode erosion, rotary arc gap (RAG) switches are proposed in previous literatures. The rotation of the arc can be achieved by providing magnetic field from external or self-induced by arc current. This paper investigates a RAG switch working in open air. It has a coaxial cylindrical structure. The arc is driven by an axial magnetic field which is generated by the coils that are placed both at the top and bottom of the switch. The coils are connected with an inner electrode. The switch can operate in a wide voltage range of 0.5-24 kV, and its specifications of current and coulomb per shot can reach 320 kA and about 730 C, respectively. The results of high-current experiments show that the electrode erosion is slight. Rotating arc velocity is measured by B-dot probes. The relationship between arc velocity and the current and magnetic flux density is obtained from the experimental data. The switch voltage drop is also measured in these experiments.