Electricity: electrical systems and devices – Safety and protection of systems and devices – High voltage dissipation
Reexamination Certificate
2000-01-13
2002-04-16
Picard, Leo P. (Department: 2835)
Electricity: electrical systems and devices
Safety and protection of systems and devices
High voltage dissipation
C361S133000, C361S115000, C200S400000, C200S237000, C218S120000, C218S142000, C218S154000
Reexamination Certificate
active
06373675
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an operating apparatus for a switching device, for example, a small-capacity vacuum circuit breaker.
A conventional operating apparatus for a small-capacity vacuum circuit breaker has a configuration as shown in
FIGS. 1 and 2
.
As shown in
FIG. 1
, a vacuum valve
53
is supported by the upper support
52
of a switchboard
51
provided on a truck. An operating rod
54
for operating the movable contact of the vacuum valve is coupled with an operating apparatus
57
provided in the switchboard
51
via an insulating rod
55
and a wiper spring
56
supported by a main shaft
69
.
As shown in
FIG. 2
, the operating apparatus
57
stores the force of a motor
58
in springs (a closing spring
59
and an opening spring
60
). Tripping catches (a closing catch
61
and a tripping catch
62
), the operating apparatus
57
releases the stored energy and is coupled with the outside world via the wiper spring
56
.
While in such an operating apparatus
57
, energy is usually stored by the motor
58
, it may be stored by engaging a hand lever (not shown) with the output shaft of the motor
58
. Although the catches
61
,
62
are normally released by the electromagnetic force of coils
65
,
66
via paddles (a closing paddle
63
and a tripping paddle
64
), they may be released by pressing buttons (a closing button
67
and an opening button
68
) with a hand.
In such a conventional operating apparatus for a vacuum circuit breaker, however, the operating apparatus is composed of a large number of component parts and is therefore large in scale. For this reason, it is required to provide an operating apparatus which is simple in mechanism and capable of operating stably by obtaining a large contact load.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an operating apparatus for a switching device which produces a large contact load with a simple mechanism and operates stably over a long stroke.
According to an aspect of the present invention, there is provided an operating apparatus for operating a switching device having a movable contact and a fixed contact so provided that they can contact each other and separate from each other, comprising: an operating rod which is fixed to the movable contact and is held such that the rod can move in a direction in which the movable contact makes into contact with or is separated from the fixed contact; a movable member which is connected to the operating rod such that the member can move relatively to the rod and the relative movement to the operating rod is limited to a specific movable range; a fixed member for holding the movable member such that the movable member can move; a first elastic member for acting the operating rod with respect to the movable member in the direction in which the movable contact is pressed against the fixed contact; a permanent magnet for attracting the movable member with respect to the fixed member; a closing magnetic circuit so constructed that, when the movable contact is in contact with the fixed contact and the switching device is closed, N and S poles of the permanent magnet attract the fixed member in the direction in which the movable contact is pressed against the fixed contact; an opening magnetic circuit so constructed that, when the movable contact is apart from the fixed contact and the switching device is open, at least one of the N and S poles of the permanent magnet attract the fixed member in the direction in which the movable contact is separated from the fixed contact; and an operating electromagnet for increasing and decreasing the magnetism in the closing magnetic circuit and the opening magnetic circuit.
The operating apparatus may further comprise a second elastic member for acting the movable member with respect to the fixed member in the direction in which the movable contact is separated from the fixed contact.
The operating apparatus may further comprise a third elastic member for acting the movable member with respect to the fixed member in the direction in which the movable contact is pressed against the fixed contact in an open position where the movable contact is apart from the fixed contact.
In the operating apparatus, if a reaction force that the operating rod exerts on the movable member by the action of the first elastic member is Fk
1
, a reaction force that the fixed member exerts on the movable member by the action of the second elastic member is Fk
2
, and the permanent-magnet-generated attracting force that the fixed member acts on the movable member is Fm, setting may be done in the movable range of the movable member such that the changing characteristic of Fk, or Fk
1
+Fk
2
, is almost equal to the changing characteristic of Fm.
In the operating apparatus, if a reaction force that the operating rod exerts on the movable member by the action of the first elastic member is Fk
1
, a reaction force that the fixed member exerts on the movable member by the action of the second elastic member is Fk
2
, a reaction force that the fixed member exerts on the movable member by the action of the third elastic member is Fk
3
, and the permanent-magnet-generated attracting force that the fixed member acts on the movable member is Fm, setting may be done in the movable range of the movable member such that the changing characteristic of Fk, or Fk
1
+Fk
2
+Fk
3
, is almost equal to the changing characteristic of Fm.
In the operating apparatus, setting may be done such that, when the movable contact is pressed against the fixed contact and the switching device is closed, an expression Fk<Fm holds, and when the switching device is open, an expression Fk>Fm holds.
In the operating apparatus, the operating electromagnet may be composed of a closing operating electromagnet located in the closing magnetic circuit and an opening operating electromagnet located in the opening magnetic circuit.
The operating apparatus may further comprise: a peep door which is provided in part of the opening magnetic circuit or the closing magnetic circuit, can be opened and closed freely, and allows the N and S magnetic poles of the permanent magnet to be peeped at; and a magnetic force short member which has such a size as can be inserted through the peed door and pressed against the N and S poles and is made of a permeability material.
In the operating apparatus, the peed door may also serve as the magnetic force short member.
In the operating apparatus, the opening magnetic circuit may be so constructed that, when the movable contact is apart from the fixed contact and the switching device is open, the N and S poles of the permanent magnet attract the fixed member in the direction in which the movable contact is separated from the fixed contact.
The operating apparatus may further comprise: a second elastic member for acting the movable member with respect to the fixed member in the direction in which the movable contact is separated from the fixed contact; and a third elastic member for acting the movable member with respect to the fixed member in the direction in which the movable contact is pressed against the fixed contact.
In the operating apparatus, if the reaction force that the operating rod exerts on the movable member by the action of the first elastic member is Fk
1
, the reaction force that the fixed member exerts on the movable member by the action of the second elastic member is Fk
2
, the reaction force that the fixed member exerts on the movable member by the action of the third elastic member is Fk
3
, and the permanent-magnet-generated attracting force that the fixed member acts on the movable member is Fm, setting may be done in the movable range of the movable member such that the changing characteristic of Fk, or Fk
1
+Fk
2
+Fk
3
, is almost equal to the changing characteristic of Fm.
In the operating apparatus, one of the N and S poles of the permanent magnet may be a part to increase a force of attraction or a force of repulsion so as to acceler
Homma Mitsutaka
Ishikawa Yoshinobu
Sato Kimiya
Taniguchi Makoto
Yamazaki Toshiharu
Kabushiki Kaisha Toshiba
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Picard Leo P.
Vortman Anatoly
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