Magnetically driven arcs with combined column and electrode interactions

In recent years, it has been found possible to correlate both the magnetic and electric characteristics for many magnetically deflected arcs. This paper shows however that large departures from the magnetic characteristics can occur. Experimental results up to arc currents of several thousand amperes, arc lengths of 11 mm and gas pressures of 11 atm indicate factors that can lead to unexpectedly slow arc movement, which may be unsatisfactory in circuit-breaker applications, both in adversely affecting the interrupting ability and because of contact damage. Indications have been found that the inadequate movement is not necessarily caused only by electron emission or arc-column friction effects, and that electrode-vapour jets are probably involved