High-voltage switches with arc preventing or extinguishing devic – Arc preventing or extinguishing devices – Housing structure
Reexamination Certificate
2000-06-23
2002-11-12
Donovan, Lincoln (Department: 2832)
High-voltage switches with arc preventing or extinguishing devic
Arc preventing or extinguishing devices
Housing structure
C218S151000
Reexamination Certificate
active
06479781
ABSTRACT:
TECHNICAL FIELD
This invention relates to circuit breaker mechanisms and, more particularly, to arc chute assemblies for circuit breaker mechanisms.
BACKGROUND OF THE INVENTION
Arc chutes or arc shields are commonly used to confine and extinguish an electric arc that is produced when the circuit breaker mechanism is tripped and the contacts are rapidly opened. A molded case circuit breaker mechanism
10
is shown in
FIG. 1
comprising a case
12
with the cover removed to show the interior components depicted in an open position. The current carrying components include two fixed contacts
14
,
16
and two movable contacts
18
,
20
attached to an operating mechanism
22
by means of a movable contact arm
24
. The operating mechanism is refrained from driving the movable contact arm and movable contact to the open position under the bias provided by a pair of powerful operating springs (not shown). The two pairs of springs provide a floating assembly of the operating mechanism
22
in an orifice
28
allowing rotation of the contact arm
24
around an axis
30
. Pairs of springs also provide the contact pressure in the closed position of the pole. Pairs of springs are arranged symmetrically with respect to axis of rotation
30
of contact arm
24
, so as to exert in any position of the contact arm
24
, a return torque of the contact arm
24
to the closed position.
In the closed position of the contact arm
24
, the fixed contact
14
cooperates with the movable contact
18
borne by the contact arm
24
, whereas the fixed contact
16
cooperates with the movable contact
20
. The current input at a given moment via an input conductor
32
flows through the fixed contacts
14
,
16
, contact arm
24
, and movable contacts
18
,
20
, and is output on the opposite side via a conductor
34
. It can be seen that the ends
36
,
38
of conductors
32
,
34
have flowing in them currents of opposite polarities to the currents flowing in the contact arm
24
, thereby generating a repulsion force moving the contact arm
24
to the open position. This looped trajectory in the zone of the contacts
14
,
16
,
18
,
20
generates a magnetic blowout field.
The magnetic blowout field comprises an arc plasma discharge that momentarily stays for a short while in the zone of fixed contacts
14
,
16
and then moves toward arc chute assemblies
40
,
42
in accordance with a sudden upward bouncing of the movable contacts
18
,
20
as a sudden disconnection.
Then, as the movable contacts
18
,
20
move upwards in the direction of arrow
43
, the stable contacts
14
,
16
become further distanced from the movable contacts
18
,
20
, and accordingly the arc moves toward an internal portion of arc chute assemblies
40
,
42
by an electromagnetic force generated between the a plurality of arc chute plates
44
and the arc current (FIG.
2
).
Referring now to
FIG. 2
, the plasma arc discharge that has moved inside the arc chute plates
44
are serially partitioned according to the arc chute plates aligned on every other floor therein, and the arc resistance becomes rapidly increased and accordingly the arc voltage becomes rapidly increased by related factors, such as cathode effect of the plates
44
in which when the arc comes into the arc chute assemblies
40
,
42
, the plates
44
are respectively turned to positive poles or negative poles, a cooling effect in which the arc is partitioned into shorter arcs between the plates
44
and extinguished in the air by cooling, and a pressure effect according to an arc energy by an increased magnetic flux density with regard to a pressure increase in the arc chute assemblies
40
,
42
.
Referring now to
FIG. 3
, the conventional arc chute assembly for extinguishing plasma arc discharge will now be described. The conventional arc chute assembly
40
includes plurality of arc chute piates
44
formed of a metal or an alloy of metals for inducing magnetism, and a plurality of sidewalls
46
formed of insulation material.
Arc chute plates
44
respectively include a plurality of engagement protrusions
48
extended from each side thereof and cut off by the respective centers thereof. The sidewalls
46
include a plurality of slots
50
for receiving corresponding ones of the engagement protrusions
48
.
The combining steps between the plates
44
and the sidewalls
46
for forming the arc chute assemblies
40
,
42
will now be described. The plates
44
including the engagement protrusions
48
are fixed using a gig and then the plates
44
are respectively inserted into a corresponding one of the engagement slots
50
formed in the sidewalks
46
. In order for the plates
44
not to escape from the sidewalls
46
, the sidewalls
46
are bound by a rubber string.
The respective cut-off portions of the engagement protrusions
48
are opened to each side thereof by employing a riveting process, thereby fixing the plates
44
to the sidewalls
46
.
Likewise, plurality of plates
44
are stacked with a space therebetween between the sidewalls
46
, and the assembled arc chute assembly
40
is mounted in the arc extinguishing chamber provided in the circuit breaker. However, the conventional arc chute assembly
40
allows the plates
44
to be inserted into the sidewalls
46
, and in order for the plates
44
not to be released from the sidewalls
46
, the sidewalls
46
are fixed by use of a rubber string and there is further followed a riveting process for the fixture.
Referring again to
FIG. 2
, the present arc chute design depicts how hot arc plasma gas generated by the opening operation between the stationary and movable contacts flows through a set of iron arc plates in the direction of arrows
52
.
As a result, there is a need for an arc chute designed to prevent discharged arc plasma gas from collecting on the contact arm.
There is also a need for an arc chute designed to promote the flow of discharged arc plasma gas through the spaces between a set of arc plates.
There is also a need for an arc chute plate design that minimizes the drag/reflecting areas at the edges of the arc chute plates.
There is also a need for an arc chute plate design having aerodynamically cut edges to facilitate the easy flow of arc plasma gas into the chute, and out of it.
There is also a need for an arc chute plate design having aerodynamically cut edges to facilitate minimal reflection of the arc plasma wave.
BRIEF SUMMARY OF THE INVENTION
The exemplary embodiments include an arc chute assembly for a circuit breaker mechanism having a pair of support members and a plurality of plates being supported by the pair of support members. The assembly has a plurality of plates that define a plurality of openings where the support members are positioned so as to define the plurality of openings. The plates each have a pair of tabs which are received in a corresponding pair of openings within each of the support members. The plates are configured to have at least one aerodynamic feature to facilitate the movement and extinguishing of discharged arc plasma waves and the plates are configured to have an opening along the periphery of one of the sides of said plates. The openings are configured to facilitate the movement and extinguishing of discharged arc plasma waves.
These and other features and advantages of the present invention will be apparent from the following brief description of the drawings, detailed description, and appended claims and drawings.
REFERENCES:
patent: 2655578 (1953-10-01), Sillers
patent: 2668890 (1954-02-01), Latour
patent: 3009041 (1961-11-01), Zlupko
patent: 3210504 (1965-10-01), Latour
patent: 3440378 (1969-04-01), Baird
patent: 4107497 (1978-08-01), Jencks et al.
patent: 4950852 (1990-08-01), Goldman
patent: 5247142 (1993-09-01), Yonkovitz et al.
patent: 5818003 (1998-10-01), Moldovan et al.
patent: 5898152 (1999-04-01), Kim
patent: 403 068 (1924-09-01), None
patent: 2 153 749 (1973-04-01), None
Bagepalli Bharat Sampathkumaran
Ciarcia Ronald
Gadre Aniruddha Dattatraya
Mundra Kamlesh
Pulido Eladia
Cabeu Christian G.
Donovan Lincoln
General Electric Company
Patnode Patrick K.
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