Patent GB-457128-A (GB)
Title: Improvements in or relating to electric switchgear
IPC: H02B1/00
Filed: 1935-05-22
Abstract: 457,128. Switchgear structures. REYROLLE & CO., Ltd., A., Hebburn-on- Tyne, ALLAN, A., Cragside, Ashleigh Grove, Tynemouth, and WILLIAMS, T., 11, Whinneyfield Road, Walker, Newcastle-on-Tyne. May 22, 1935, No. 14944. [Class 38 (v)] Indicators.-Switchgear having in association with main breakers, isolating and other auxiliary switches controlling the main circuits controlled by the breakers, comprises the combination with a mimic diagram representative of those circuits, of actuating devices for the auxiliary switches located on the diagram at or near the position representing such switches, a direct operative mechanical connection from each actuating device to the corresponding auxiliary switch, and a movable indicating member carried by or mechanically connected to each actuating device for indicating on the diagram the position of the associated switch. The invention is shown applied to switchgear as described in Specification 425,107 in which a number of bus-bar sections normally form a ring in each phase and T-connections to the incoming and outgoing circuits are taken from the ring at junction points between the sections, each T-connection being controlled by a main breaker. The gear is arranged in panels, each associated with a junction point, one panel being shown in Fig. 1. Each bus-bar section comprises an insulated conductor in an oilfilled conduit connecting upper chambers B of two adjacent panels. Each upper chamber B is partitioned at B<2> to provide two chambers per phase, the larger B<3> containing the connections from the bus-bars to the main breaker A and the smaller B<4> those from the breaker A to the external circuit. The six compartments intercommunicate and a float-operated, oillevel alarm B5 is provided. The isolating and sectionalizing switch comprises a sector contact E extending over 240‹ mounted on an insulating member E <1> which is rotatable through 60 or 120‹ in one direction and through 60‹ in the reverse direction so as to connect the breaker contact A<5> to either or both bus-bar contacts C<1>, C<2> or to isolate it, leaving the ring intact, the change-over from one contact to the other being through the position shown, so as not to interrupt the supply. Contacts A<5>, C', C<2> are in the form of bundles of spring-pressed plungers making butt contact, and A<5> is angularly displaced by 60‹ from the line of C<1>, C<2>. The incoming cable D passes through a current-transformer housing D<3> to the movable contact J of a cable-isolating switch, and is also connected over contact D<5> to a withdrawable potential transformer L, the insulated conductors L<2> of which can be withdrawn by mechanism L<3>, whereupon sluice valves L<4> close the orifices in the chamber-extension. Contacts D<5> are carried by hollow insulators D<6>, testing orifices in which are normally covered by plates D<7>. The bus-bars are earthed by means of switches F engaging metal collars C<3>, the switches F of the three phases being mounted on a common shaft F<1> for simultaneous operation. Earthing switches G, H, K are provided for contacts A<5>, A<6>, and the cable, respectively and similarly mounted on common shafts G<1>, H<1>, K<1>. The shafts F<1>, G<1>, H<1>, K<1> and the rotatable insulating members E<1>, J<1> carrying the isolating switches pass into a separate chamber at the front of the gear, Fig. 3, the outer wall M<1> of which bears the mimic diagram of circuits controlled by the breakers and auxiliary switches. The movable indicating members F<2>, J<2>, K<2> of switches F, J, K are carried by hollow actuating shafts F3, J<3>, K<3> which are connected by suitable linkage with the respective shafts F', J<1>, K1 and also by further linkage to secondary switches in a top compartment M<2>. Thus, the shafts F<1>, F3 carry cranks F<4>, F<6> interlinked by F<5>, and the additional link is shown at F', similar arrangements being provided for J<3>, K<3>. Shafts G<1>, H<1> are directly connected, for conjoint operation, by link G<5>, and the crank H<4> on shaft H<1> is connected by link H<5> to the shaft H<3> carrying the indicator H<2>. The indicator G<2> is carried by a simple spindle G<3> which, with shaft G<1>, is linked to a crank on a vertical spindle G<11> actuating a mechanical interlock (not shown) to prevent lowering of the breaker tank A unless both sides of the breaker are earthed. The actuating member E<3> of the switch E is located on the diagram a little way away from the position of the indicator E<2>, and operates gearing E' ... E<7> to drive the latter, the spindle of which carries a sprocket E<14> which actuates through a chain E<15> secondary switches in M<2>. The gearing is preferably such that three revolutions of E<3> rotate E<2> through 60‹. The gear E<6> also drives a gear E<4> which is of the same size as E' and is carried by spindle E<10> which is coaxial with E<1> and drives the latter through cranks E<11>, E<12>, and link E<13>. The main breaker is motor or solenoid-operated under control of a handle O on the diagram or of a remote handle, each handle having a lock O<1> and a single key O<2> being provided for both locks to prevent simultaneous operation. The spindle of the control handle O carries a crank O<5> controlling the breaker-operating gear electrically through a link O<6> and the handle O is movable from a central inoperative position to one side or the other for tripping or closing the breaker, the key being only removable in the inoperative position of the handle O. Alternative mechanical control as described in Specification 457,127 may also be provided. The indicator A<8> of the breaker is mounted on a hollow shaft and linked at All, A<12> to the breaker-operating mechanism so as always to indicate the position of the contacts. The shafts F3, J3, H3, K3 are locked by means which is under control of electromagnets P<4>, the energizing circuits of which are controlled by interlock contacts, some of which are the switches in M<2>, and by a switch adjacent the electromagnet, which switch is preferably of the press-button type and is closed by means of a spindle in the hollow shafts F<3> &c. prior to operation by the common handle N. The spindle is depressed by means of the pin N<1> on a push-button N<2> located in the handle N. The locking means each carry an indicating arm visible through a window M<3> in the diagram, and the handle N can be operated on receipt of an indication that the mechanism is " free," whereupon the button N<2> is released. In the case of the cable-earthing switches K, the barrel of a further lock R can only be rotated to permit operation of the other unlocking means, when a special key has been inserted. The switches E<2> have discs S, T mounted on the shafts E<3>, the discs being notched as at T<1>, Fig. 4, for engagement by noses as S2, Fig. 4, on catch arms S<3>, T<3> pivoted at S', T<4>, the notch on S preventing clockwise rotation and the notch T<1> preventing counterclockwise rotation. The arms S<3>, T<3> are operated by electromagnets S5, T<5> under control of interlock contacts and of switches U, U<1> which are operated from the button N<2> and rod U<6>, Fig. 4, through a lever U' and cross-bar U<2>. Indicators S<6>, T<6> are pivoted on the arms S<3>, T<3>, which also carry rollers S<8>, T<8> engaging notches in a disc E<16> on the spindle E<8> to prevent automatic locking after each revolution of the spindle E<8> once the button N<2> is released. Modifications comprise the use of separate unlocking push-buttons in the ends of the actuating shafts, the use of repeat relays in the interlocking circuits to save wiring, the use of an electromagnetic instead of a mechanical interlock to control the lowering of the breaker tank in accordance with the condition of the breaker earthing switches, and the use of locks for the cover of the bus-bar compartment and cable-testing orifice.