US2054674A

US2054674A - Electrical switch gear

Info

Publication number: US2054674A
Application number: US33985A
Authority: US
Inventors: Charles H Hill; Kenneth T Ashdown
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1935-07-31
Filing date: 1935-07-31
Publication date: 1936-09-15
Anticipated expiration: 1953-09-15

Description

Sept. 15, 1936. c. H. HILL ET AL ELECTRICAL SWITCH GEAR Filed July 31, 1935 ISM/6 77 Their Attorney Patented Sept. 15, 1936 PATENT OFFICE ELECTRICAL SlvVITCH GEAR Charles H. Hill and Kenneth T. Ashdown, Drexel Hill, Pa., assignors to General Electric Company, a corporation of New York 7 Application July 31, 1935, Serial No. 33,985

Claims.

Our invention relates to electrical switchgear,

more particularly to means for interlocking the opening and closing operations of two or more circuit breakers; In certain installations two or more circuit breakers are arranged for alternatively controlling a circuit or circuits. Where circuit conditions require a definite and predetermined order of operation, such as maintaining one breaker open when another breaker is closed, reliable interlocking means must be provided. I The principal object of our invention is the provision of improved circuit breaker controlling and interlocking means for two or more breakers which shall besirnple and compact in design and positive and reliable in operation.

' Our invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize our invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is an elevational view, partly in section, of switchgear of the drawouttype embodying our invention; Fig. 2 is a simplified plan'view, looking downwardly, of part of the interlocking mechanism of the switchgear shown by Fig. 1, and Fig. 3 is a perspective View or" the essential elements of the aforesaid interlocking mechanism,

Referring to Fig. 1, the draw-out type switchgear illustrated byway of example, comprises a movable truck portion l mounted on wheels 2 and a stationary portion or housing 3 in which stationary conductors or busbars of the circuit, or circuits, to be controlled are mounted. The truck I is suitably formed of structural steel framework and supports a circuit breaker 4, anoil circuit breaker of conventional design being shown in the present instance.

In operation, the circuit breaker i is electrically connected to circuits in the stationary portion 3 through disengageable disconnect contacts 5 of suitabledesign, the connection at ii being broken and thecircuit breaker isolated when the truck i is rolled. towards the left, as viewed in Fig.1.

The operating means for the breaker l may comprise any suitable arrangement, a simple manual operating mechanism being illustrated comprising a hand lever 5 pivoted to a stationary part of the truck frame at l, a connecting link 8, thrust transmitting toggle 9 and breaker operating lever ID. The breaker i closed by straightening of the toggle 9 and raising of the lever is.

Opening of the breaker may be eifected manually or by the usual trip coil at H through the trip lever 52 and latch indicated at l3, permitting the link 8 to move towards the left with respect to hand lever B byreason of the slot [4, thereby causing collapse of the toggle 9.

For the purpose of preventing destructive arcing at the disconnect contacts 5 by withdrawal of the truck while the breaker 4 is closed, suitable interlocking means is provided for tripping the breaker immediately upon withdrawal of the truck. In the present instance a rod i5 is operatively connected tothe rackout mechanism at [6 so as to actuate the trip lever l2 through lever i1 and crank I 8 when the truck is withdrawn. The rackout mechanism comprises a worm gear mounted on the truck and a coacting stationary rack, the worm gear being rotated by a socket wrench, or the like, exteriorly of the truck for moving the same with respect to the stationary portion 3.

The rod l5, which is normally biased down- Wards as by gravity or spring force, is likewise connected through a compression spring I9 to a pivoted latch 26 which is biased by the spring I9 so as to engage and hold, when in open circuit position, the end 2! of a bellcrank 22 forming part of the toggle 9. The switchgear arrangement so far described is illustrated and disclosed in more detail in Patent No. 1,791,466 to H. G. French entitled Electric Switching Devices.

A plurality of truck-type units may be arranged in a row to form a station as indicated by Fig. 2 which illustrates two trucks l and I movable with respect to the stationary circuit housing 3. In the interest of clearness, the plan view, Fig. 2, omits the circuit breakers and operating mechanisms.

For the purpose of interlocking the operations of the breakers in the truck units l and I, mechanical means are arranged between the operating mechanism of each breaker and the tripping mechanism of the other breaker, causing in the present instance tripping of one breaker upon closing of the other breaker and vice versa. The arrangement, while permitting both breakers to be in open circuit position, permits but one breaker at a time to be in closed circuit position.

To this end a pair of independently

rotatable shafts

23 and 24 are suitably mounted in the housing 3 in bearings 25, the shaft 24 being in the form of a sleeve mounted on and freely rotatable with respect to the shaft 23. Each shaft is provided with means for interlocking the operating mechanism of one breaker and the tripping mechanism of the other breaker.

Referring more particularly to Fig. 3 wherein the breakers in the truck units I and l are referred to as A and B, respectively, a bellcrank 26 suitably mounted on the truckframe at 2! is connected through a link 28 to the bellcrank 22 of the operating toggle. The bellcrank 26 is likewise connected to a rod 29 which may engage in abutting relation a lug 30 secured to the shaft 24. As illustrated, the linkage arrangement connected to breaker A is in the closed circuit position so that opening of the breaker and clockwise rotation of the bellcrank 26 merely moves the rod 29 away from abutting engagement with the lug 3! without rotating the shaft 23.

The tripping mechanismof the breaker B comprises a rod IS on which is'secured a'collar 3! arranged to coact with a bifurcated arm 32 of a bellcrank 33 which is mounted on the truck frame at 34. V is connected to a rod 35 which, as in the case of rod 29, is arranged to abut a lug 30' secured to the shaft 24 in spaced angular relation with respect to lug 30. The relation between the lugs 38 and 30 is such that when the breaker A is closed the rod 29 moves the lug 30 to such position that the lug 35 holds the rod 35' and bellcrank 33 in the position shown wherein the tripping rod I is in the tripping position. Accordingly, when the breaker A is in closed circuit position it is impossible to close breaker B by reason of the inoperative condition of its tripping mechanism.

Assuming now that breaker A is opened, thereby causing movement of rod 29 away from lug 30, the downward bias on rod l5 'resets the tripping mechanism of breaker B and causes clockwise rotation of lug 30' through crank 33.

Closing of thebreaker B may now be effected,

causing counterclockwise rotation of bellcrank 26 through the upward movement of rod 28 and movement of rod 29 towards 'theright to 'and 36' are mounted in spaced angular relation engage lug 36 which is secured to one end of the shaft 23. The shaft is accordingly rotated in a counterclockwise direction as is the lug 36 which is secured to the other end of the shaft As in the preceding instance, the lugs 36 vided with a bifurcated arm 32' coacting with a collar 3! secured to the rod I5. Accordingly, counterclockwise rotation of shaft 23 in response to closing of the breaker B causes clockwise rotat'i'onof bellcrank 33 and elevation of the rod I5 to the tripping or inoperative position.

It will, therefore, be noted that either breaker may be closed when the other breaker is open and that when both breakers are open the tripping mechanism of each is operative so that either one may be closed. Closing of both breakers at the same time, however, is positively precluded.

The interlocking arrangement disclosed is particularly advantageous in installations where a plurality of interchangeable switch units of the draw-out type are required for the purpose of maintaining practical continuity of operation. An individual truck unit may immediately be removed from the station without affecting the in-.

The other arm of the bellcrank terlocking arrangement between the same and another breaker and a similar unit may be moved without delay into operative position without requiring any connections or adjustments between the truck unit and interlocking arrangement. Since each breaker of an interlocked pair ispractically identical with the other, any breaker is interchangeable with any other in an installation using a number of pairs of interlocked breakers of like capacity. It will be apparent, of course, that the interlocking arrangement above described is not limited to twobreakers, and that, for example, breakers in'pairs may be interlocked with respect to'other pairs.

It should be understood that our invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of our invention. 7 t 7 What we claim as new and desire to secure by Letters Patent of the United States is: 7 1. In electrical switchgear including a plurality of circuit breakers, each breaker having a tripping mechanism and an operating mechanism, means for interlocking said breakers com prising a rotatable shaft operatively related to the operating mechanism of one breaker and the tripping mechanism of another breaker respectively, and a second rotatable shaft operatively related to the tripping mechanism of said firstnamed breaker and the operating mechanism of said other breaker respectively.

2. In electrical switchgear including a plurality of circuit breakers, each breaker having a tripping mechanism and an operating mechanism, means for interlocking said circuit breakers comprising a member operatively related to the operating mechanism of one of said breakers, a sec-- ond member movable with said first member in fixed relation thereto and operatively related to the tripping mechanism of another of said breakers, a third member operatively related to the tripping mechanism of said first-named breaker, and a fourth member movable with said third member in fixed relation thereto and operatively related'to the operating mechanism of said other breaker.

3. In electrical switchgear including a'plurality of circuit breakers, each' breaker having a tripping mechanism and an operating 'mechanism, means for interlocking said circuit breakers comprising a rotatable shaft, interlock members secured to said shaft in fixed spaced relation,

,means operatively connected to the operating mechanism of one breaker and the tripping mechanism of another breaker arranged to engage in abutting relation said interlock members respectively, and a second rotatable shaft having similar interlock members arranged to engage in abutting relation means operatively connected to the tripping mechanism of said first-named breaker and the operating mechanism of said other breaker respectively.

4. In truck type electrical switchgear including a plurality of movable circuit breakers, each breaker having a tripping mechanism and an operating mechanism, means for interlocking said circuit breakers comprising a rotatable shaft having a pair of interlock member secured thereto in spaced angular relation, one of said members arranged to engage in abutting relation means operatively connected to the closing mechanism of. one of said breakers, the other of said members arranged to engage in abutting relation means operatively connected to the tripping mechanism of another of said breakers, a second shaft arranged in concentric relation and freely rotatable with respect to said first shaft, a pair of interlock members secured in spaced angular relation to said second shaft, one of said lastnamed members arranged to engage in'abutting relation means operatively connected to the tripping mechanism of said first-named breaker and the other member arranged to engage in abutting relation means operatively connected to the closing mechanism of the other breaker.

5. In a station including a plurality of similar switchgear units 01' the draw-out type, each of said units having tripping means and actuating means, means for interlocking pairs of said units comprising means mounted independently of said units and actuated thereby for controlling the tripping operation of one unit in accordance with the actuating operation of the other unit, each of said units being freely withdrawable with respect to said interlocking means and interchangeable with any other of said units.

CHARLES H. HILL. KENNETH T. ASHDOWN.