ES371161A1 - Pneumatic operating mechanism for a circuit interrupter with piston device having an opening piston and a closing piston - Google Patents

Abstract

A high-speedactuator 27 for a gas blast switchcomprises a closing piston 16 and a larger opening piston 15 operating in a cylinder 20, 21 and coupled to a movable contact of the switch (29, Fig. 6, not shown).. Upward movement of a pull rod 14 moves the contact (29) to its open position, allowing blast gas to enter the nozzle-shaped contacts, and closes a downstream blast valve (33, Fig. 6, not shown) towards the end of the opening movement. The upper side of the closing piston 16 is always subject to the high pressure of SF 6 in the contact space the lower side of the opening piston 15 is connectable by a control valve 23 either to the high-pressure or to a low-pressure chamber to close or open the switch respectively. In order to slow the movement of rod 14 at either end of its travel a piston 18 is mounted on the rod and moves in a cylinder 41 filled with high pressure SF 6 and having apertures 41a in its walls and non-return valves 45, 46 in its ends the apertures 41a are adjustable by screws 43. In order to ensure a constant opening and closing speed the flow of gas to and from the space below piston 15 is controlled by a valve 35 (Fig. 10, not shown) responsive to the-high pressure. In a three phase arrangement (Figs. 1-4, not shown) the three operating rods are coupled together to a common actuator (2) at ground potential. Each of the three switches has a generally U-shaped configuration (Figs. 5A, 5B, 5C, not shown) comprising in one arm .the contacts, blast valve and actuator 27 and in the other an SF 6 filled terminal insulator current transformers (C.T.) are fitted near the base portion.