3-electrode surge protective device

摘要

The 3-electrode surge protective device includes: a surge protective device body including: an earth electrode; a ceramic cylinder; and a pair of line electrodes; and a fail-safe spring including: an elastic mount portion; and a short-circuit portion, a conductive material that is sandwiched between the fail-safe spring and the body; and a pair of first lead pins provided on the pair of line electrodes; a second lead pin provided on the earth electrode. In a normal state, the conductive material support the short-circuit portion at a separation position where the short-circuit portion is separated from the outer peripheral face of the body and the first lead pins. In case where the body is overheated and the conductive material is melted, the short-circuit portion is moved to a contact position where the short-circuit portion comes into contact with the second lead pin and the first lead pins.