Total voltage drops in electrode fall regions of , argon and air arcs in current range from 10 to 20 000 A

Measurements were made of the sum of cathode fall and anode fall voltages, i.e. electrode fall voltages for , argon and air arcs at a pressure of 0.1 MPa in wide current range from 10 to 20 000 A. For each arc, copper - tungsten, copper, iron and tungsten were used as electrode materials. The arcs proved to have electrode fall voltages of 17.5, 17.5, 17.5 and 13.8 V at the Cu - W, Cu, Fe and W electrodes respectively. The electrode fall voltage of each arc was affected by the electrode material. It was also found that the electrode fall voltage of each arc at a given electrode was independent of current in the above range. Further, the electric field strength at cathode surface and thickness of cathode fall region were estimated on the basis of Temperature-and-Field emission theory.