| 摘要 |
1,151,831. Arcing preventing in switches. GENERAL ELECTRIC CO. 8 Jan., 1968 [24 Feb., 1967], No. 996/68. Heading H1N. A resistor 30 is connected across each pair of contacts 12, 14 of a multi-break circuit-breaker by means of a triggered spark gap 32 during closing. The vacuum gaps 32 are of the kind comprising main electrodes 46, 48a and auxiliary electrodes 58, 60 of titanium with absorbed hydrogen; when a pulse from a source 70 is applied to electrodes 58, 60 an arc is struck between them which feeds plasma to the main gap 50. An arc then strikes across the main gap 50 to connect the resistor 30 across main contacts 12, 14. The source 70 is operated by an S.C.R. which is rendered conductive by light transmitted from a lamp 75 by fibre optics 73. The lamp 75 is energized, after contacts 85 are closed by initial movement of main contacts 14, by a timing circuit 80 so that all sources 70 provide triggering pulses within a few microseconds of the voltage zero. Shortly after 85 another contact 92 closes and an oscillator 90 provides repetitive pulses to maintain the arc across gap 50 until contacts 12, 14 are fully closed when a cam switch 86 disconnects the lamp. The oscillator is omitted if gap 32 is of the low pressure gas filled type which maintains the arc after current zero. Both electrodes of the gap 50 may be triggered (Fig. 1a, not shown). In a modification (Fig. 2, not shown) the resistor and spark gap are connected between the fixed contact 12 and an auxiliary contact (100) thus providing an isolating gap (102) in the open position. The resistors may be connected across the main contacts during opening as well by means of auxiliary switches (110) (Fig. 3, not shown), or by making one contact of the spark gaps movable to engage the other when the main contacts close (Fig. 4, not shown). |
