| 摘要 |
<p>An electrical circuit breaker (10) comprises an enclosure (12) filled with an insulating fluid. Within the enclosure (12) is a pair of opposing contacts (14 and 16) one of which is fixed and the other moves axially relative thereto. When the contacts (14 and 16) are separated an arc is drawn between them. The arc is rotated by a magnetic field generated by coil (18). A shield (20) prevents the arc short circuiting the coil (18) but also traps ionised gas particles and metallic vapours. To prevent the ionised gas and vapours building up a flow of purging gas is directed through channels (26 and 28) to region A. The purging flow of gas flushes out this region to prevent re-establishment of the arc.</p> |
