| 摘要 |
<p>658,600. Air-blast switches. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Aug. 8, 1949, No. 20554. Convention date, Aug. 9, 1948. [Class 38(v)] To enable the supply of compressed air to an air-blast switch to be reduced immediately after the arc has been extinguished, the switch 1 is supplied from a container 8 through blast valves 9 arranged in parallel in the air supply system, one of the valves remaining open after the others have automatically reclosed. When the switch is opened the operating solenoids 12, 13 of the valves 9 are are energized and the valves open simultaneously. Compressed air is supplied to the air-blast switch 1 through the blast pipe 10 and through a pipe 18 and chamber 17 to a cylinder containing a piston 16. After the slight delay imposed by the chamber 17 the piston 16 opens contacts 15 to interrupt the current to the two lower solenoids 12. Hence the two lower valves 9 reclose whilst the uppermost valve remains open to permit a small supply of air to the switch to prevent reignition of the arc. An isolating switch 4, 6 may be provided.</p> |
