Bochum 2015 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 23: Plasma Technology II
P 23.3: Vortrag
Mittwoch, 4. März 2015, 17:25–17:40, HZO 30
Electrical and optical investigations of constricted high-current vacuum arcs — •Kristoffer Ole Menzel1, Nils Lukat1,2, and Markus Abplanalp1 — 1ABB Switzerland Ltd, Corporate Research Center, 5405 Baden-Dättwil, Switzerland — 2IEAP, CAU Kiel, D-24098 Kiel
Vacuum interrupters (VI) represent the state-of-the-art technology for high-current interruption at medium AC-voltages of 1kV-36kV. While breaking the current a vacuum arc is ignited between the contacts of the VI. The arc is sustained by copper vapor from the hot electrodes. For high currents above 10kA the arc is found to burn in a constricted mode at very high current densities of the order of 108A/m2. In order to reduce the thermal load of the VI in this regime a transverse magnetic field (TMF) can be generated between the contacts that move the arc over the electrode surfaces. As this approach is very common for real devices the underlying physical process have to be known in great detail. To systematically investigate such arcs a simple electrode setup was designed that allows for an easy access of all employed diagnostics. We used spatially resolved optical emission spectroscopy in order to obtain the spatiotemporal temperature distribution. Moreover, an electrostatic Langmuir probe allowed to deduce plasma properties in the vicinity of the arc, where the emitted light intensity is comparably low. In this contribution, measurements of the main characteristics of constricted arcs are presented. We will discuss the main results of our investigations, as e.g., the establishment of a constant temperature profile for almost all examined maximum currents.