Magnetic Forces on Gas Blast Interrupter Arcs Due to Electrode Shape

Nozzle electrode shape in a gas blast circuit interrupter can cause very large magnetic forces to act on the arc. A rapid and inexpensive method for computing these forces is described. A conformal mapping technique is used in approximating the non-symmetrical 3-dimensional electrode current distribution by a large number of straight line segments of current. Superposition of the effect of each element determines the field at points of interest in the arcing region. Significant advantage exists over methods using numerical solutions of partial differential equations when knowledge of the, field is required at relatively few points.