Information
-
Patent Grant
-
6483065
-
Patent Number
6,483,065
-
Date Filed
Tuesday, October 9, 200122 years ago
-
Date Issued
Tuesday, November 19, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Patnode; Patrick K.
- Cabou; Christian G.
-
CPC
-
US Classifications
Field of Search
US
- 218 118
- 218 120
- 218 127
- 218 134
- 218 137
- 218 139
- 218 140
- 218 154
- 218 155
- 200 8907
- 200 275
- 200 281
-
International Classifications
-
Abstract
Methods and apparatus for facilitating current transmission through a circuit breaker are described. In an exemplary embodiment of the apparatus, a coupler that includes a copper conductive ring having an inner annular wall is provided. The coupler is electrically coupled to the line terminal. A bore extends through the ring, and the bore is sized so that the shaft can extend therethrough. A plurality of copper bristles extend radially inward from the ring inner annular wall, and the bristles are in electrical contact with the conductive ring. The bristles also are in electrical contact with shaft when shaft extends through ring bore. At least some bristles extend sufficiently radially inward from the ring inner wall so that free ends of at least some bristles are in electrical contact with the shaft when the shaft extends through the bore.
Description
BACKGROUND OF INVENTION
This invention relates generally to circuit breakers and more particularly, to transmitting current from a movable element of a circuit breaker to a line terminal.
A circuit breaker typically includes a stationary contact and a movable contact located in an arc chamber. The stationary contact is in electric circuit with a first line terminal, and the movable contact is in electric circuit with a second line terminal. For example, the movable contact is coupled to a conductive shaft that is movable towards and away from the stationary contact. The conductive shaft moves relative to the second line terminal, and the electrical connection between the conductive shaft and second line terminal permits such movement while maintaining electrical contact. For example, a spring-loaded finger arrangement can be provided that includes conductive spring-loaded fingers biased into electrical contact with the shaft.
During normal operation, i.e., when no fault occurs, the movable contact is in electrical contact with the stationary contact, and current at a rated level flows through the breaker. Specifically, current at the rate level flows from the first line terminal to the second line terminal via the stationary and movable contacts and the spring-loaded finger arrangement.
Once a fault occurs, the shaft is driven by the trip mechanism so that the movable contact moves away from the stationary contact to interrupt current flow. The spring-loaded finger arrangement permits relative movement of the shaft with respect to the second line terminal yet maintains electrical contact with the shaft. The shaft can be driven so that the movable contact moves towards and into electrical contact with the stationary contact by operating the closing mechanism. The spring-loaded finger arrangement also permits this relative movement of the shaft with respect to the second line terminal while maintaining electric continuity.
SUMMARY OF INVENTION
In one aspect, a coupler for coupling a movable shaft of a circuit breaker with a line terminal is provided. In an exemplary embodiment, the coupler includes a copper conductive ring having an inner annular wall, and is electrically coupled to the line terminal. A bore extends through the ring, and the bore is sized so that the shaft can extend therethrough.
A plurality of copper bristles extend radially inward from the ring inner annular wall, and the bristles are in electrical contact with the conductive ring. The bristles also are in electrical contact with shaft when shaft extends through ring bore. Specifically, at least some bristles extend sufficiently radially inward from the ring inner wall so that free ends of at least some bristles are in electrical contact with the shaft when the shaft extends through the bore.
In another aspect, a method of assembling a coupler and a movable shaft of a circuit breaker is provided. In an exemplary embodiment, the method includes the steps of aligning the shaft with the bore through the conductive ring, and inserting the shaft through the bore so that at least some bristles are in electrical contact with the shaft shaft. As explained above, the ring is in electrical circuit with line terminal. In operation, as the shaft moves relative to the coupling, the bristles maintain electrical contact between the shaft and the coupling.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1
is a side view of a portion of a breaker assembly.
FIG. 2
is an end view of a coupler.
DETAILED DESCRIPTION
FIG. 1
is a side view of a portion of a breaker assembly
10
. Assembly
10
includes a breaker housing
12
that houses a movable contact and a stationary contact (the contacts are not shown). A first line terminal
14
is in electrical contact with the stationary contact. A movable shaft
16
extends into housing
12
and is coupled to the movable contact. Generally, shaft
16
is movable relative to housing
12
in the directions indicated by arrow
18
.
Shaft
16
extends through a coupling
20
, and coupling
20
is in electrical circuit with a second line terminal
22
. Shaft
16
also moves relative to coupling
20
. As shaft
16
moves relative to coupling
20
, coupling
20
maintains electrical contact with shaft
16
so that a current can continue to flow from first line terminal
14
, and through the stationary and movable contacts if such contacts are in circuit.
FIG. 2
is an end view of coupling
20
including a cross-sectional view of shaft
16
extending therethrough. Coupling
20
includes a copper conductive ring
24
having an inner annular wall
26
. An outer annular wall
28
of coupling
20
is electrically coupled (e.g., welded) to line terminal
22
(FIG.
1
). A bore
30
extends through ring
24
, and bore
30
is sized so that shaft
16
can extend therethrough.
A plurality of copper bristles
32
extend radially inward from inner annular wall
26
, and bristles
32
in electrical contact with conductive ring
24
. In the exemplary embodiment, bristles
32
have an outer layer of silver and are welded to inner annular wall
26
.
Bristles
32
are in electrical contact with shaft
16
when shaft
16
extends through ring bore
20
. Specifically, at least some bristles
32
extend sufficiently radially inward from ring inner wall
26
so that free ends
34
of at least some bristles
32
are in electrical contact with shaft
16
when shaft
16
extends through bore
30
. The number and size (e.g., cross-sectional area) of bristles
32
are selected so that bristles
32
do not inhibit the rated current flow through the breaker. In addition, the number and length of bristles
32
affects the loading on shaft
16
in that such bristles
32
resist motion of shaft. Therefore, the dimensions of bristles
32
are selected to place a desired loading on shaft
16
to reduce friction losses on shaft
16
during breaker opening and closing operation, compared to friction losses that occur with the spring loaded finger arrangements described above. In addition, bristles
32
are positioned so that bristles
32
maintain uniform contact with shaft
16
and so that if some bristles lose contact with shaft during motion, other bristles
32
maintain such contact with shaft
16
.
To assemble coupling
20
and shaft
16
, shaft
16
is aligned with conductive ring
24
and inserted through ring
24
so that at least some bristles
32
are in electrical contact with shaft
16
. Ring
24
is in electrical circuit with line terminal
22
(FIG.
1
). In operation, as shaft
16
moves relative to coupling
20
, bristles
32
maintain electrical contact with shaft
16
.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
Claims
- 1. Apparatus for transmitting current from a movable element of a circuit breaker to a line terminal, said apparatus comprising:a conductive ring having an inner annular wall, a bore extending through the ring, said bore sized so that the circuit breaker movable element can extend therethrough, said ring configured to be connected in an electrical circuit with the line terminal; and a plurality of bristles in electrical contact with said conductive ring and extending radially inward from said inner annular wall of said ring, said bristles configured to be in electrical contact with the movable element when the movable element extends through said ring bore.
- 2. Apparatus according to claim 1 wherein said conductive ring is copper.
- 3. Apparatus according to claim 1 wherein said bristles are copper.
- 4. Apparatus according to claim 1 wherein said bristles comprise an outer layer of silver.
- 5. Apparatus according to claim 1 wherein at least some of said bristles extend sufficiently radially inward from said ring inner wall so that free ends of at least some of said bristles are in electrical contact with the circuit breaker movable element when the movable element is positioned to extend through said bore.
- 6. A method for assembling a circuit breaker, the circuit breaker including a movable element and a conductive ring, the conductive ring having an inner annular wall and a plurality of bristles extending radially inward from the inner annular wall, said method comprising the steps of:aligning the movable element with conductive ring; and inserting the movable element through the conductive ring so that at least some of the bristles are in electrical contact with the movable element.
- 7. A method according to claim 6 wherein the movable element is movable relative to the conductive ring.
- 8. A method according to claim 6 further comprising the step of securing the ring in an electrical circuit with a line terminal.
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A |
4568804 |
Luehring |
Feb 1986 |
A |
5001312 |
Barber et al. |
Mar 1991 |
A |
5055640 |
Lippi et al. |
Oct 1991 |
A |
5422450 |
Miyazawa et al. |
Jun 1995 |
A |
6198062 |
Mather et al. |
Mar 2001 |
B1 |