ABSTRACT
The vacuum arc is the name given to the arc which is formed between contacts that operate in a vacuum (26,44,45). The vacuum arc is an arc that forms in metal vapor evaporated from the contacts themselves. It can be formed either from vacuum breakdown of an open contact gap (see Sect. 8.3.2) or during contact parting by the rupture of the molten metal bridge (see Sect. 8.4.2). After the rupture of the molten metal bridge, a highpressure column arc is formed called the bridge column (25,46,47) which can persist for times up to a millisecond, see Fig. 8.35.
