GB2289794A

GB2289794A - A tripping arrangement for a circuit breaker

Info

Publication number: GB2289794A
Application number: GB9506576A
Authority: GB
Inventors: Roger Neil Castonguay; James Lawrence Rosen; Mark Albino Zaffetti
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1994-04-13
Filing date: 1995-03-30
Publication date: 1995-11-29
Anticipated expiration: 2015-03-30
Also published as: GB9506576D0; GB2289794B

Abstract

An apparatus for releasing circuit breaker contacts comprises a contact delatching device 1, 2 for releasing the contacts, a first tripping device 4 for mechanically actuating the contact delatching device, a second tripping device 5 for electromechanically actuating the contact delatching device and a linkage 3 for coupling the first and second tripping devices to the contact delatching device. <IMAGE>

Description

TRIPPING ARRANGEMENT FOR HIGH AMPERE-RATED CIRCUIT BREAKER US Patent 4,001,742 entitled "Circuit Breaker Having Improved Operating Mechanism" describes a circuit breaker capable of interrupting several thousand amperes of circuit current at several hundred volts potential. As described therein, the operating mechanism is in the form of powerful operating springs that are restrained from separating the circuit breaker contacts by means of a latching system. This latching system is described in US Patent Application Serial No. 08/205,240, filed 3 March 1994, entitled "Latching assembly for high ampere-rated circuit breaker" a copy of which is at the Annex to this application.

According to the present invention an apparatus for releasing circuit breaker contacts comprises a) a contact delatching means for releasing circuit breaker contacts; b) a first tripping means for mechanically actuating said contact delatching means; c) a second tripping means for electromechanically actuating said contact delatching means; and d) a linkage means for coupling said first and second tripping means to said contact delatching means.

The linkage means or the coupling means may comprise: a) a first pin means; b) a trip arm means which, when contacted by said first tripping means, is displaced about said first pin means.

In this case the contact delatching means may comprise a) a D-latch means; b) a D-latch arm means; and c) a latching assembly means which is released when said trip arm means is displaced in a first direction and contacts said D-latch arm means so as to release said latching assembly means and, conveniently, comprise a) a first surface means on said D-latch arm means; and b) a second surface means on said trip arm means which contacts said first surface means when said trip arm means is displaced in a first direction.

The first tripping means may comprise a) a frame means; b) a second pin means on said frame means; c) a trip button means displaced about said second pin means so that said trip button means when displaced in a second direction contacts and displaces said trip arm means with, optionally a third surface means on said trip button means that contacts and displaces a fourth surface means on said trip arm means when said trip button means is displaced in a second direction.

In this embodiment the apparatus may include a spring that biases said trip button means in a rest position and further comprise a fifth surface means on said trip button means that contacts a fourth pin means when said trip button means is in the rest position.

The second tripping means may comprise a) a lever means; and b) an electric trip unit means which when actuated displaces said lever means so that said lever means contacts and displaces said trip arm means, the lever means being, for example, displaced about the first pin means.

Such apparatus may comprise a) a tab means on said lever means; and b) a plunger means, in said electric trip unit means, which when displaced by said electric trip unit means contacts said tab means so as to displace said lever means or comprise a) a third surface means on said lever means; and b) a third pin means on said trip arm means that contacts and displaces said trip arm means when said electric trip units means is actuated.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which Figure 1 is a diagrammatic perspective view of circuit breaker incorporating an embodiment of the present invention; Figures 2, 3 and 4 are diagrammatic end views of the embodiment of Figure 1 in rest, depressed and tripped configurations, respectively; and Figure 5 is a diagrammatic exploded perspective view of the embodiment of Figures 2 to 4.

Figure 1 shows a latch assembly 12, a trip button 4, a trip arm 3, an electric trip unit 5 and a D-latch arm 2. The present invention provides a means to release such a latching system allowing the circuit breaker contacts to part.

The release arrangement in Figure 2 consists of a Dlatch 1, a D-latch arm 2, a trip arm 3, a trip button 4, an intermediate trip arm 6, a pin 7 and an electric trip unit 5.

Figure 5 shows an exploded view of this tripping arrangement along with side frames 16 and 17.

The trip button 4 is connected to the mechanism side frame 16 by means of the trip button pivot pin 14. The trip arm 3 and the intermediate trip arm 6 are connected to the mechanism side frame 16 by means of the trip arm pivot pin 15. All of these components are free to rotate about their respective pivot pins. The electric trip unit 5 is also mounted to the mechanism side frame 16 in such a manner a plunger 5a of the electric trip unit can interface with tab 6a of the intermediate trip arm 6.

This release system has two modes of operation, a manual mode where the system is operated by means of the trip button 4, and an electric mode where the system is operated by means of the electric trip unit 5.

The operation of the manual system is best seen by referring jointly to the "rest" configuration shown in Figure 2 and the "depressed" configuration shown in Figure 3.

Initially the trip button 4 is in its "rest" position as shown in Figure 2. The trip button is biased clockwise about the trip button pivot pin 14 by a spring (not shown) until a stopping surface 4a on the trip button 4 contacts an intermediate closing arm pivot pin 20. This contact sets the rest position of the trip button 4.

The trip arm 3 is positioned at "rest" by contact between a surface 3a on the trip arm 3 and a surface 2a on the D-latch arm 2 or by contact between a surface 3b on the trip arm 3 and pin 7 which is mounted to the intermediate trip arm 6. The trip arm 3 is allowed to rotate about the trip arm pivot pin 15, between the stop points 2a on the D-latch arm 2 and pin 7.

The intermediate trip arm 6 is positioned at "rest" by contact between tab 6a on the intermediate trip arm 6 and plunger 5a on the electric trip unit 5 of contact between pin 7 mounted on the intermediate trip arm 6 and surface 3b on the trip arm 3. The intermediate trip arm 6 is allowed to rotate about the trip arm pivot pin 15, between the stop points pin 7 and plunger 5a of the electric trip unit 5.

When the trip button 4 is depressed the bias force holding it in its "rest" position is overcome and the trip button rotates counter-clockwise about the trip button pivot pin 14. The surface 4b on the trip button 4 then engages the surface 3c on the trip arm 3 causing thetrip arm 3 to rotate in a clockwise direction about the trip arm pivot pin 15. As the trip arm 3 rotates contact is made between surface 3a on the trip arm 3 and surface 2a on the D-latch arm 2. As the trip arm 3 is rotated further the D-latch arm 2 forces the counter-clockwise rotation of the D-latch 1 to which it is attached. This counter-clockwise rotation of the delatch 1 releases the latch assembly 12 allowing the opening springs not shown to part the circuit breaker contacts.

When the electric trip unit 5 is used to release the latching system the trip button 4 remains stationary in its "rest" position. The plunger 5a on the electric trip unit 5 extends to contact tab 6a on the intermediate trip arm 6 this causes the intermediate trip arm 6 to rotate clockwise about the trip arm pivot pin 15. Pin 7 which is attached to the intermediate trip arm 6 is moved into contact with surface 3b of the trip arm 3 causing the trip arm 3 to rotate clockwise until contact is made between surface 2a on the D-latch arm 2 and surface 3a on the trip arm 3. As trip arm 3 is rotated further the Dlatch arm 2 forces the counter clockwise rotation of the D-latch 1 to which it is attached. This counterclockwise rotation of the D-latch 1 releases the latch assembly 12 allowing the opening springs not shown to part the circuit breaker contacts.

Claims

1. An apparatus for releasing circuit breaker contacts comprising a) a contact delatching means for releasing circuit breaker contacts; b) a first tripping means for mechanically actuating said contact delatching means; c) a second tripping means for electromechanically actuating said contact delatching means; and d) a linkage means for coupling said first and second tripping means to said contact delatching means.

2. The apparatus of Claim 1 wherein said linkage means comprises a) a first pin means; b) a trip arm means which, when contacted by said first tripping means, is displaced about said first pin means.

3. The apparatus of Claim 2 wherein said contact delatching means comprises a) a D-latch means; b) a D-latch arm means; and c) a latching assembly means which is released when said trip arm means is displaced in a first direction and contacts said D-latch arm means so as to release said latching assembly means.

4. The apparatus of Claim 3 comprising a) a first surface means on said D-latch arm means; and b) a second surface means on said trip arm means which contacts said first surface means when said trip arm means is displaced in a first direction.

5. The apparatus of Claim 2 wherein said first tripping means comprises a) a frame means; b) a second pin means on said frame means; c) a trip button means displaced about said second pin means so that said trip button means when displaced in a second direction contacts and displaces said trip arm means.

6. The apparatus of Claim 5 comprising a third surface means on said trip button means that contacts and displaces a fourth surface means on said trip arm means when said trip button means is displaced in a second direction.

7. The apparatus of Claim 6 having a spring that biases said trip button means in a rest position and further comprises a fifth surface means on said trip button means that contacts a fourth pin means when said trip button means is in the rest position.

8. The apparatus of Claim 1 wherein said coupling means comprises a trip arm means, which when contacted by said second tripping means, is displaced about a first pin means.

9. The apparatus of Claim 8 wherein said contact delatching means comprises a) a D-latch means; b) a D-latch arm means; and c) a latching assembly means which is released when said trip arm means is displaced in a first direction and contacts said D-latch arm means so as to release said latching assembly means.

10. The apparatus of Claim 9 comprising a) a first surface means on said D-latch arm means; and b) a second surface means on said trip arm means which contacts said first surface means when said trip arm means is displaced in a first direction.

11. The apparatus of Claim 8 wherein said second tripping means comprises a) a lever means; and b) an electric trip unit means which when actuated displaces said lever means so that said lever means contacts and displaces said trip arm means.

12. The apparatus of Claim 11 wherein said lever means is displaced about said first pin means.

13. The apparatus of Claim 11 comprising a) a tab means on said lever means; and b) a plunger means, in said electric trip unit means, which when displaced by said electric trip unit means contacts said tab means so as to displace said lever means.

14. The apparatus of Claim 11 comprising a) a third surface means on said lever means; and b) a third pin means on said trip arm means that contacts and displaces said trip arm means when said electric trip units means is actuated.

15. An apparatus substantially as hereinbefore described with reference to the accompanying drawings.