Arc-extinguishing circuit breaker - uses auxiliary separating contacts operating in magnetic field to lengthen and extinguish arc

摘要

The mobile contact of the circuit breaker is a vertical rod (28), which in its operated condition, rests between two spring loaded contacts (12, 14) at its top end. The rod is lowered and separated from those contacts to break the circuit. As it travels downwards, another pair of arc-extinguishing contacts (42, 44) is separated by a cone-shaped unit (60) of refractory material mounted on the vertical rod. Simultaneously, a magnetic field is created in a coil (32) around the electrodes and the arc length is increased. This causes it to be extinguished. The whole unit is sealed in a container of sulphur hexafluoride. The design provides simple mechanical linkage and rapid arc extinction.