| 摘要 |
719,732. Switchgear structures; automatic circuit breakers; liquid-break switches. ELECTRIC CONSTRUCTION CO., Ltd., and HOLMES & CO., Ltd., W. C. Aug. 27, 1953 [May 28, 1952], No. 13582/52. Class 38(5) [Also in Group XXXV] A supply system for electrostatic rectifiers PC1-PC6 comprises enclosed rectifier units RU1- RU3 each connected to an individual busbar BI-B3, and a selector switch (designed to operate also as an overload circuit breaker) SS1-SS6 for each, precipitator whereby any precipitator may be connected to any busbar, the switches and busbars being mounted in a common oil-filled casing provided externally with means for operating the switches. An auxiliary contact 7 on each switch is arranged to earth the associated precipitator when the switch is in the off position. An elaborate system of interlocks allows access to the interior of the casing only when the switches are in the earthing position and prevents reclosure of the switches until the casing has been relocked. The locking system is also such that access to the interior of any rectifier unit is possible only after the supply to that unit has been switched off and the unit earthed. The busbars are arranged in the casing at different levels, to any of which the contact 6 of each selector switch may be positioned by means of an insulating rod 52, which supports the contact, and a gate 53, 54, Figs. 5, 8. The contact 6 is connected to the selected busbar by rotation of the contact about the axis of the rod 52 by an external handle 65. The contact 6 is carried by a metal member 60, Fig. 8, attached to rod 52 and sliding over a cylindrical contact 51 on an insulating tube 50 surrounding the rod and mounted for rotation about a vertical axis in the casing. The contact 51 also carries the earthing contact 7 and a slip ring 49 which connects by a contact 48 to the associated precipitator through the winding of an overload relay OR1- OR6. Closure of the selector switch, which is normally urged to the off' position by a spring 66, Fig. 13, which tends to rotate in anticlockwise direction a plate 71 secured to the upper end of tube 50, is effected first by anticlockwise rotation of handle 65 until a pawl 68 carried thereby snaps over a pin 70 carried by the plate, and then by clockwise rotation-during which the tube and handle move as a unit-until a pawl 73 on a fixed pivot engages behind an ear 78 on the plate 71 and holds it in this position-which. corresponds to the 'on ' position of the switch. The switch is tripped either automatically by a tripping coil TR1-TR6 energized on operation of the associated overload relay or manually by anticlockwise rotation of the handle 65, when the pawl 73 is lifted clear of ear 78 by the tail of pawl 68. The tripping coil has a plunger 75 which upon energization of the coil, presses directly on the tail of pawl 68 and indirectly on the tail of pawl 73, so that both pawls are released and the switch returned to the ` off ' position by springs 66. |
