Importance

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Abstract

A surge arrester is described, comprising a first and a second electric terminals (1, 2) for connection to live and guard/neutral conductors of an electric system, between which a protection member (3) is connected, provided with a voltage electrode and with a protective electrode equipped with respective electrical connectors (1a, 3a) electrically connected to said electric terminals (1, 2), a disconnector electrically arranged between said protection member (3) and said second electric terminal (2) comprising a metal lamina (4) failing in the presence of short-circuit currents exceeding a preset threshold, said failing generating plasma, and an intercepting slider (6), mounted elastically biased and sliding in a sliding and guiding chamber crossed by said lamina (4), displacement of said interception slider (6) being prevented by said lamina (4) and being allowed by the failing of said lamina (4), and further comprising an arc extinguishing chamber (CI) provided with a divergent duct (10) and a respective inlet portion (10a) defined by end portions of a pair of divergent conductors (11a, 11b), wherein said inlet portion (10a) is arranged in fluidic communication with said sliding and guiding chamber and has an opening facing a pressure wave front generated by said displacement of the interception slider (6) acting as a plunger.

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First Claim