| 摘要 |
<p>On opening of a circuit breaker, an end portion 19 of a pivotable contact arm 12 disengages from fixed contacts 7 such that an arc is drawn therebetween radially across the pole face of a field coil 9, the end portion 19 moving transversely to the field coil axis. The arc then transfers from the contacts 7 to a tubular electrode 24 thereby bringing the field coil 9 into circuit so that a magnetic field is generated which causes the arc to rotate and become extinguished. In the fully-open position of the circuit breaker, the end portion 19 lies along the field coil axis. The whole assembly is disposed in a housing 2 which contains the highly insulating gas sulphur hexafluoride. A single field coil and electrode can be shared between two such constructions. Arrangements are also disclosed in which the initial arc is drawn directly between the contact arm 12 and the electrode 24.</p> |
