| 摘要 |
1,076,874. Gas blast switches. ETABLISSEMENTS MERLIN & GERIN S.A. May 14, 1965 [May 28, 1964], No. 20401/65. Heading H2B. A gas blast circuit-breaker of the type in which the contacts are first separated by a distance favourable to extinction of the arc produced by a short-circuit current, then pause while the arc is subjected to the gas blast and then move to a maximum distance apart as described in Specification 972,710 is modified so that the gas blast continues until after the maximum separation is reached. The bores 41, 60 in the valves 37, 46 which govern the period for which the blast valves 34, 25 remain open are calibrated so that at the end of the pause valve 25 closes bringing the contact 23 to the fully open position and a short while later valve 34 closes to shut off the blast. This is stated to improve the reversed phase interrupting ability of the switch, i.e. where currents are smaller and recovery voltages are higher than with a short-circuit. |
