The evolution of high current D.C. arcs on rotating anodes
Abstract
In this thesis the results of a program of research on the
evolution of high current d.c. arcs in air at atmospheric pressure are
presented. A technique was developed suitable for the study of high
current arc discharges, and in particular of the anode properties of
such discharges. The apparatus incorporated an electrode system
containing a rotating anode with high precision control and monitoring
facilities.
Research was carried out in the current range 10 to 1500A
for electrode separations of up to 15mm and surface speeds up to 32ms⁻¹. Two new transitions in arc properties were discovered and
investigated in detail for discharges burning between fixed thoriated
tungsten cathodes and moving anodes of copper, nickel, stainless steel
and aluminium. Discharge properties in the specified current range
were studied and the transitions identified were placed in context in
the evolution of the high current arc discharge.
The experimental technique developed proved to be eminently
suitable for studying the detailed structure of high current arcs. The
results obtained revealed a number of important avenues for further
research into the properties of high current discharges and suggested
several diagnostic techniques which should greatly enhance the
capabilities of the apparatus.