Patent GB-190701099-A (GB)
Title: Improvements in and relating to Electric Switches.
Filed: 1907-01-15
Granted: 1908-01-15
Abstract: 1099. British Thomson-Houston Co., [General Electric Co.]. Jan. 15. Switches cut-outs.-Relates to operating-mechanism for opening and closing electric switches for high-voltage circuits, and also to hamd and automatic tripping-mechanism for use in connexion therewith. The three-phase high-voltage switch shown has three sets of contacts in oil vessels enclosed in separate chambers. The chambers,. Figs. 1 and 2, are built up on a back supporting-wall with beams 2, fire-proof partition walls 3, top and bottom parts 4; 5 of insulating- material, and removable metal doors 6. The rods 7 carrying the contacts are made of wood or other insulating-material, and pass through the caps 4. They are connected to the operating-mechanism, which comprises rods 10, Fig. 4, the forked ends of which are jointed to arms 9 rocking on pivots fixed to bases 8 mounted on the caps 4. Each arm 9 is coupled through a parallel-motion linkage to a long horizontal rod 23, which transmits the force for actuating the switch. The linkage is composed of two bars 16,19 forming a closed parallelogram with the links 9, 10, a link 20 pivoted at one end to a fixed point of the base, a link 17, and a bellcrank 21 also pivoted to a fixed point of the base. At the joint 12 of the links 9, 10 is a spring 11 shown in dotted lines, which tends always to open the parallelogram and raise the rod 7 to the 'off' position. A spring 25, connected to the rod 23 and to a fixed point of the base 8, also tends to open the switch by moving the rod 23 to the left. The rod 23 is connected by way of a toggle joint 26, 27, Fig. 6, which forms a temporary rigid connexion, when overset, to a bell-crank 29, thence through a hanging connecting-rod 32, Fig. 7, a bell-crank 33, and a link 34, to a hand or power operated lever 35, which is mounted on a base 36 secured to the floor of the station. The base bas a spring-latch 37 normally holding the lever 35 in the position it assumes when the switch is closed, and a foot-plate 40 for depressing the latch and permitting the switch to open. The switch can also be opened by tripping the toggle 26, 27 automatically or by hand. For this purpose is provided a trippingslever 43, Fig. 6, normally held down below the toggle-joint by a spring 46. An arm 47, rigidly fixed to the spindle 41 of the lever 43, and having a hanging handle 48, Fig. 2, permits of the hand tripping of the toggle-joint. The automatic tripping- means are shown in Figs. 9 and 10, and comprise a wooden lever 58, a rod 55, a bell-crank 53, and a rod 50, which is connected to a crank 49 on the shaft 41 carrying the trip-lever 43. The mechanism is actuated by an overload trip-coil. The particular form of solenoid described below, and the connexion between it and the tripping-mechanism, do not form part of the invention, and are described by way of example only. The coil 59 is connected in series in the high-tension circuit through terminals 73, 75, all the metal framework of the coil being at the same tension as the lead 73, in order to avoid strains on the coil insulation. The other terminal 74 is carried on a fibre plate 75. The attracted core 63 is initially outside the solenoid coils, making a large air gap and keeping the impedance low. It is connected, to the link 72 by weak springs 69 and by a rod 65 passing through a hole in a cross-piece 68. A nut 66 on the rod 65 meets the cross-piece 68 and carries it downwards after the core has moved far enough to acquire ttie necessary force. The initial position of the striking part and the joints may be adjusted by a nut 67 and slotted links 70. The special form of oil vessel described in the Provisional Specification in connexion with Fig. 3 forms the subject-matter of Specification No. 1099A, A.D. 1907.