The chemistry of electric fuse arcing

Experimental investigation of the fusion in cylindrical exploding wires using high current densities with industrial frequency

“…3). During this process, the heavily ionised surrounding air is considered that is operating in the smaller gap (smaller length) [1,5,7,10,11,16,17]. The development of the wire fragmentation in exploding wires and the plasma formation in experiments above mentioned have been observed, and described also in M.J. Taylor's recent works.…”

“…If the source voltage of the circuit is sufficiently high, small arcs arise between these globules. This phenomenon is referred as "multiple arcing" and it has been observed [1,2,3,7,16]. With the volatilization and interruption of the metallic coherence, electric arcs are formed (arcing period) between the remaining solid parts of the conducting material, in an environment of metal vapors.…”

“…The fuse resistance in these circumstances is determined by the cross-section of the metal vapor column, the length of this column and the specific resistance of the ionised metal vapor. Experiments showed that the cross-section of the metal vapor column depends on the current [1,2,7,17]. In this metal vapor column the arcs are formed.…”

“…There is a rapid change in arc dimensions, which is a function of the rate of burnback of the metallic parts (arc elongation). This dynamic process gives rise to rapid increase in the electric resistance of the arc and its eventual extinction [1,2,3,6,12]. The metal vapor column, which arises during the evaporation process of a fusing wire surrounded by air, expands very rapidly due to the high pressure in this vapor, as has been made visible with cylindrical wires in the past [7].…”

“…They generally operate either under a minus value of their nominal current or momentarily under excess or sort-circuit currents. During the operation under nominal current or less the Joule heating produced on fuse element dissipates to the surrounding area of the element and thermal equilibrium is attained after a time period [1,2,3,4]. For the case of the operation under excess or heavy fault currents the design of fuses is based on the well known fundamental principle, that they must interrupt those currents in a very sort time period.…”