Electricity: electrical systems and devices – Control circuits for electromagnetic devices – For relays or solenoids
Reexamination Certificate
1999-10-08
2001-09-25
Fleming, Fritz (Department: 2836)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
For relays or solenoids
C361S154000
Reexamination Certificate
active
06295192
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a switchgear in which an electrode opening or closing operation is performed when the electrode contacts or separates, particularly to a switchgear having a simplified structure and improved performance.
2. Description of the Related Art
FIGS. 25A and 25B
show a switchgear similar to a conventional switchgear using electromagnetic repulsion as shown in Japanese Patent Publication No. 7-60624. Further,
FIG. 25A
shows the closed electrode state and
FIG. 25B
shows the opened electrode state.
In the figures, a switch
1
has a movable electrode
5
and a fixed electrode
6
. The movable electrode
5
is fixed to a movable conductive rod
4
. A repulsing section
2
is fixed to the movable conductive rod
4
. A coil
3
for inducing current in the repulsing section
2
is fixed to a coil holder
9
. The repulsing section
2
is pushed by a spring (coil spring)
8
so as to contact the movable electrode
5
with the fixed electrode
6
. One end portion of the movable conductive rod
4
is inserted into a latch
7
. The repulsing section
2
, movable conductive rod
4
, and movable electrode
5
are fixed and constituted on the axis of the electrodes
5
and
6
. The coil
3
is connected to magnetic-field generating power supply.
Next,
FIG. 26
is an illustration showing load characteristics of a coil spring used as the loading spring
8
. In
FIG. 26
, numeral
49
denotes deflection of the spring used,
50
denotes deflection in an electrode closed state,
51
denotes deflection in the opened electrode state,
52
denotes a spring load under the closed electrode state, and
53
denotes a spring load under the opened electrode state.
Next, the operation will be described. In
FIGS. 25A and 25B
, when current is supplied to the coil
3
, a magnetic field is generated. Thereby, an induced current is generated in the repulsing section
2
to provide an electromagnetic repulsion against the coil
3
. When the electromagnetic repulsion exceeds the spring load
52
during the closed electrode state shown in
FIG. 26
, the repulsing section
2
, movable conductive rod
4
, and movable electrode
5
operate in the same direction as the electromagnetic repulsion and the switch
1
opens. Then, the latch
7
keeps the positions of the repulsing section
2
, movable conductive rod
4
, and movable electrode
5
in an opened electrode state, the switch
1
can then be closed in accordance with the load of the loading spring
8
by releasing the latch
7
. As shown in
FIG. 26
, because the spring constant of the coil spring is constant, the spring load
53
in the opened electrode state exceeds the load
52
under the closed electrode state.
As described above, because the conventional switchgear uses the coil spring as the loading spring
8
and the spring load under the opened electrode state is larger than that under the closed electrode state, the spring energy must be large while the closed electrode state changes to the opened electrode state, therefore requiring unnecessary electromagnetic repulsion energy. Moreover, conventional switchgear needs a latch mechanism to maintain the opened electrode state. Therefore, when the electrode opening speed increases, the latch performance can not keep up with the speed and thus, the opened electrode state cannot be maintained. Furthermore, because the closing operation is performed by releasing the latch
7
, there are problems in that it takes time for the latch releasing mechanism to begin operation, delaying the closing operation.
SUMMARY OF THE INVENTION
The present invention has been achieved with a view toward solving the problems described above, and it is an object of the present invention to provide a switchgear which is capable of reducing the spring energy needed to change from a closed electrode state to an opened electrode state as well as reducing the load on a latch or eliminating the latch to perform a fast opening/closing operation.
To this end, according to one aspect of the present invention, there is provided a switchgear, comprising: a pair of electrodes; a tripping mechanism for opening the electrodes; an opened electrode state holding mechanism for holding the electrodes open; a closing mechanism for closing the electrodes; and a loading spring for loading the electrodes; wherein the spring constant of the loading spring can be changed during closing and opening operations.
According to another aspect of the present invention, there is provided a switchgear, comprising: a pair of electrodes; a tripping mechanism for opening the electrodes; an opened electrode state holding mechanism for holding the electrodes open; and a closing mechanism for closing the electrodes; wherein the opened electrode state holding mechanism uses a loading spring in which a load in the opposite direction to the load under the closed state works under the opened electrode state.
According to a still further aspect of the present invention, there is provided a switchgear comprising a pair of electrodes, a tripping mechanism for opening the electrodes, and a closing mechanism for closing the electrodes; wherein the tripping mechanism and the closing mechanism are provided with a repulsing section and an electrode closing coil and an electrode opening coil for generating a repulsive force in the repulsing section, or provided with an electrode-closing repulsing section, an electrode-opening repulsing section, and an electrode closing-and-opening coil for generating a repulsive force in both repulsing sections, and an electrode closing capacitor for supplying current to the electrode closing coil or the electrode closing-and-opening coil when closing the electrode, an electrode opening capacitor for supplying current to the electrode opening coil or the electrode closing coil when opening the electrode, and a charging power supply for charging the electrode closing and opening capacitors.
According to a still further aspect of the present invention, there is provided a switchgear comprising a pair of electrodes, a tripping mechanism for opening the electrodes, and a closing mechanism for closing the electrodes; wherein the tripping mechanism and closing mechanism provided with a repulsing section and an electrode closing coil and electrode opening coil for generating a repulsive force in the repulsing section, and a capacitor for supplying current to the closing coil or electrode opening coil, a charging power supply for charging the capacitor, and closing and electrode-opening change means for selectively changing electrode-opening and closing operations so that current can be supplied from the capacitor to the closing coil or electrode opening coil.
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T/23 036 (51) H 01 33/35 (71) Hungarian Abstract, Jul. 28, 1982.
Kishida Yukimori
Koyama Ken-ichi
Maruyama Toshimasa
Nishimiya Kazuhiko
Sasao Hiroyuki
Fleming Fritz
Mitsubishi Denki & Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
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