Patent GB-1022811-A (GB)
Title: Improvements in or relating to switching apparatus
IPC: H01H3/46
Filed: 1963-11-01
Abstract: 1,022,811. Electromagnetic switches; air break switches; protective systems; switchgear structures. WESTINGHOUSE ELECTRIC CORPORATION. Nov. 1, 1963 [Nov. 7, 1962 (3)], No. 43217/63. Headings H2B and H2K. In a protective switchgear system comprising a main electromagnetic contactor 20-22 closed by depressing a push-button 34 and opened by depressing a push-button 56 or by an overload responsive bimetal switch 58, fuses 26 in series with the main contacts 22 are arranged to pivot about one terminal to make and break contact with its other terminal and thus to act as a series isolating switch. The coil 30 of the contactor 20 is controlled by a relay 36, 40 and the contactor has additional contacts 68 to hold on the relay after push-button 34 is released. The contactor and relay are energized through rectifier 32 from a transformer 44 between two phase lines or for test purposes from an auxiliary supply 55. The three-phase contactor 20 and the three-phase fuse-isolator 26 are each mounted on a separate horizontally withdrawable carriage 92, 94 in a cabinet 90 while the auxiliary equipment (outside dashed line of Fig. 1, not shown) is mounted directly in the cabinet. Each of the fuses 26 is mounted at one end in a cradle 130 (Figs. 3, 4, not shown) where it is gripped in the on position by a sprung arm 276; the cradle also carries one fixed contact 122 of the contactor 20. The other end of the fuse carries a jaw 286 (Figs. 6, 7, not shown) forming the movable isolator contact and being engageable through an aperture 343 in the carriage 92 with a fixed contact 294 mounted in the cabinet and connected with one of the supply lines S. The clips 286 are pivoted to a sliding carriage 288 (Fig. 5, not shown) movable to open and close the isolator by a handle 386 pivoting at 388 in a support 390. The support (Fig. 11, not shown) is also angularly movable to lock or unlock the door 100 of the cabinet and is arranged so that the door can only be unlocked when the isolator is open and the isolator can only be operated when the door is in the closed position and locked. The slide 288 is prevented from movement while the contactor 20 is closed by engagement between two levers 446, 460 (Figs. 9, 10, not shown) the first 446 of which engages with abutments 458, 454 on the slide; movement of the slide 288 is also prevented by levers 446, 460 when the door 100 is open, a toggle linkage 482, 492 having been moved overcentre by a hook 488 on the door. Slide 288 is coupled to a shutter 500 which is moved to cover apertures 343 when the isolator is open; the shutter also carries indicia visible through the door 100 to indicate the condition of the isolator. Each phase of the contactor includes a blowout coil 160 (Figs. 3, 4, not shown) having a core 164 and polepieces 202 and an arc chute 162 comprising a plurality of parallel insulating plates 183 and arc runners 188, 190 connected with the contacts 122, 124; the arc chute is detachable by means of blade and clip connectors 192, 194; 196, 198 and is held in place by bolts through its side plates 184 screwed into the cores 164 of the blow-out coils. The moving contacts 124 are pivoted to and spring-urged from carrier 140 insulatingly clamped to a rod 144 which also carries the armature 222 (Figs. 9, 10, not shown) of the actuating electromagnet 220. The armature carries a pin 250 engaging a slotted lever 245 which actuates the auxiliary switch 68.