High-voltage switches with arc preventing or extinguishing devic – Arc preventing or extinguishing devices – Auxiliary shunt
Reexamination Certificate
2001-11-05
2003-08-05
Donovan, Lincoln (Department: 2832)
High-voltage switches with arc preventing or extinguishing devic
Arc preventing or extinguishing devices
Auxiliary shunt
C335S068000, C335S076000, C335S077000
Reexamination Certificate
active
06603087
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a switch-disconnector control unit. A switch-disconnector is used to form a safe clearance between an electric circuit to be disconnected and other electric circuits, or it is used to de-energize a part of the electric circuit in order to assure the safety of the work.
BACKGROUND OF THE INVENTION
Switch-disconnectors are used in electricity distribution networks. A switch-disconnector is used to form a safe clearance between an electric circuit to be disconnected and other electric circuits, or it is used to de-energize a part of the electric circuit in order to assure the safety of the work. For this purpose, the switch-connector is arranged to be controlled between three switching positions. These positions are: disconnector closed, disconnector open and disconnector earthed. In the close position, the disconnector connects an electric circuit disconnected by means of said disconnector to another electric circuit. In the open position, the disconnector disconnects the electric circuit disconnected using said disconnector from another electric circuit. In the earthed position, the disconnector earths the electric circuit disconnected using said disconnector to be de-energized in order to assure the safety of the work.
Manually operated switch-disconnector control units are previously known in the art that are controlled using a crank connected to the control shaft of the disconnector. This requires the presence of a physical person to control the procedure, who carries out the control in the immediate vicinity of the switch-disconnector. It is also known to use remote-controlled control units provided with a motorized actuator that can be controlled either manually or using remote control for controlling the disconnector. These disconnector control units comprise a spring actuator connected to the control shaft of the disconnector. The spring in the spring actuator is tightened using a motorized actuator. When the motorized actuator has rotated the control shaft to the tripping point of the spring, the spring trips and provides an adequate amount of strength to open or close the contact of the switch-disconnector.
Control units for bistable switch-disconnectors are also previously known in the art. In such a case, the positions concerned are close and open. Newer types of switch-disconnectors also comprise an earth switch integrated to the switch-disconnector and a spring actuator. Thus, the spring actuator comprises three positions: open, close and earthed. The spring actuator may alternatively be provided with two control shafts or two control points in order to switch said actuator between the open and close positions and between the open and earthed positions. Such a conventional switch-disconnector provided with an earth switch comprises a manual control unit and a motor-operated control unit, which opens and closes the main circuit of the switch-disconnector. Said switch-disconnector further comprises a separate manually operated control unit, which opens and closes a separate or integrated earth switch. In addition, one or more very complicated blocking mechanisms are required to prevent malfunctions, such as the simultaneous closing of the switch-disconnector and the earth switch. The structure of such a switch-disconnector control unit is very complex and liable to malfunction, as it comprises a plurality of separate structural parts, wherefore it is also expensive to implement.
A general requirement for a switch-disconnector is that switching between open and earthed positions can only be carried out manually and the switching between open and closed positions can be performed both manually and using remote-control.
Significant drawbacks are thus associated with the prior art. The prior art switch-disconnector control units described above are manually operated or motor-operated if they are remote controlled, whereby the structures thereof are complicated and liable to malfunction and as regards the switching speed very slow. What is also essential is that remote control to the earthed position is prevented, which requires very complex blocking mechanisms in the prior art solutions.
BRIEF DESCRIPTION OF THE INVENTION
It is an object of the present invention to eliminate the drawbacks of the prior art and to provide an improved solution for a switch-disconnector control unit and to provide a switch-disconnector control unit comprising a single control shaft that enables to switch the switch-disconnector between the open and close (OPEN-CLOSE) positions and between the open and earthed (OPEN-EARTHED) positions. Switching between the open and close positions (OPEN-CLOSE) is carried out manually by turning the control crank connected to the control shaft of the disconnector or by means of remote control (an automatic actuator) by turning the control shaft of the disconnector. Switching between the open and earthed positions (OPEN-EARTHED) can only be carried out manually by turning the control crank of the disconnector. In addition the control motion provided by the remote-controlled actuator between the open and close positions (OPEN-CLOSE) and vice versa is fast and strong, but the actuator does not, however, prevent the manual control of the switch-disconnector.
This is achieved with a switch-disconnector control unit provided with the characteristics defined in the claims in accordance with this invention. The switch-disconnector control unit comprises an actuator including a moving control member and a spring actuator including a control shaft, whereby the control member is connected from the first end thereof to the actuator and from the second end thereof to the control shaft of the spring actuator, whereby the control shaft is arranged to control the contacts of the switch-disconnector using the spring actuator, and the invention is characterized in that the control member comprises a connection element, which connection element is jointedly connected from the first end thereof to the control shaft through a control member, and from the second end thereof the connection element is jointedly connected to the control member of the actuator, and an articulated joint at the second end of the connection element is substantially formed of an opening parallel to the control shaft in the vicinity of the end of the connection element and of a pin parallel to the control shaft connected to the control member of the actuator substantially in the vicinity of the end of the connection element side thereof, the pin being arranged to the opening, which is dimensioned to be large in relation to the pin.
In other words, the actuator in the control unit comprises an electromagnet, the armature of which linearly moves the control arm, which is connected from the first end thereof to the control shaft controlling the contacts of the switch-disconnector using the spring actuator through the control member and from the second end thereof to the armature of the electromagnet. The control member comprises a connection element, which is jointedly connected from the first end thereof to the control shaft and from the second end thereof jointedly connected to an arm part connected to the armature of the electromagnet. The articulated joint at the second end of the connection element, or at the armature end, is substantially formed of a preferably oval opening parallel to the control shaft the end of the connection element and of a pin parallel to the control shaft connected to the arm part in the vicinity of the to the control shaft connected to the arm part in the vicinity of the end of the connection element thereof, and said arm part being connected to the armature of the electromagnet, and the pin is arranged to said oval opening.
The preferred embodiments of the invention are disclosed in the dependent claims.
In the solution of the invention the oval opening at the end of the actuator in the connection element connected to the control member moving the control shaft preferably resembles an ellipse in the longitudinal direction of the
Österholm Nils
Östersund Per-Erik
ABB Technology Ltd.
Donovan Lincoln
Dykema Gossett PLLC
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