GB1098380A - A gas blast circuit breaker - Google Patents

Abstract

1,098,380. Gas blast switches; electrically released switches. GENERAL ELECTRIC CO. Nov. 24, 1965 [Dec. 29, 1964 (2)], No. 49858/65. Heading H2B. A gas blast circuit breaker has a blast valve assembly 36 movable by gas pressure under the control of a pilot valve 70, the blast valve 36 acting upon a crosshead 30 to move the contacts 24 to the open position where they are held by a latch (130) (Figs. 5, 6, not shown) engaging with a roller 132. The crosshead 30 is attached to damper pistons 60, 150 which control the opening and closing movements of the contacts respectively. A control rod 104 extends through the crosshead 30; this rod 104 is coupled to a control linkage (Figs. 5, 6, not shown) which is moved to the open position by a pneumatic cylinder (190) and held by a latch (140) which is releasable by a solenoid (144) to close the breaker. To open the breaker rod 104 is drawn rapidly downwards taking with it a piston 102; a partial vacuum thus created between them causes a second piston 100 to follow piston 102 thus opening the pilot valve 70. Compressed gas then flows from the containing tank (Fig. 1, not shown) through channels 56, 57, 73 to a space 66 above a piston part 65 of the blast valve 36, the other side 109 of piston 65 is vented through channels 110, 84. As piston 102 moves down compressed gas enters between pistons 102, 100 through channel 58 but valve 70 is held open, by compressed gas passing through a channel 80 to a space 78 above a piston 75 attached to the movable valve member 71, until blast valve 36 reaches its fully open position when a channel 92 supplies gas through an adjustable valve 108 to the other side of piston 75 permitting pilot valve 70 to reclose under spring 77 and the blast valve 36 to reclose under a number of tight springs (119) (Fig. 2, not shown). When rod 104 is returned to the closed position by releasing latch (140) a further linkage releases the main latch 130 and the contacts reclose under the action of compressed gas on the underside of the crosshead 30. All the control channels are vented while the contacts are closed.