High-voltage switches with arc preventing or extinguishing devic – Arc preventing or extinguishing devices – Air-current blowout
Reexamination Certificate
1999-12-13
2001-01-23
Donovan, Lincoln (Department: 2832)
High-voltage switches with arc preventing or extinguishing devic
Arc preventing or extinguishing devices
Air-current blowout
C218S084000, C218S154000
Reexamination Certificate
active
06177643
ABSTRACT:
FIELD OF THE INVENTION
The present invention is in the field of high-voltage circuit-breakers and is to be used in the structural design of an auxiliary gearing which is used to move switching elements located axially opposite the driven contact set of the circuit-breaker.
BACKGROUND INFORMATION
In circuit-breakers of this type, two arcing contact pieces, located coaxially opposite each other, are coaxially surrounded by the two continuous-current contact pieces, of which one is arranged in a fixed position and the other one is axially driveable. Circuit-breakers of this type generally operate with a gaseous quenching medium which, in a switching operation, is first compressed and then flows through the separation area of the two arcing contact pieces, it being possible to influence its flow by special pressure spaces and nozzles. Used for this purpose, inter alia, is an insulating nozzle which is arranged inside the continuous-current contact pieces and surrounds the arcing contact pieces, and which is firmly connected both to the driveable continuous-current contact piece and to the driven arcing contact piece.
In a known circuit-breaker described in, for example, (European No. 0 696 040), a field electrode, which is secured to the end of the insulating nozzle facing away from the first driven arcing contact piece and can be axially displaced together with the insulating nozzle, surrounds the second arcing contact piece and, when the circuit-breaker is in the OFF position, influences the electric field in the area of the other arcing contact piece and of the electrically heavy-loaded end of the insulating nozzle. In addition, in this circuit-breaker, the second arcing contact piece can be driven in the opposite direction of the first arcing contact piece. To this end, a driving element is secured to the axially displaceable field electrode, and thus to the insulating nozzle, the driving element transferring the driving motion of the driven continuous-current contact piece to the second arcing contact piece as well, using a deflection (corner) gear. Therefore, the second arcing contact piece is guided in a sliding contact. The driving element in the deflection gear is designed as a gear rack which either acts via a gear wheel upon the second arcing contact piece, also designed as a gear rack, or which drives a thrust crank whose rotating part is formed by a gear wheel.
In this circuit-breaker, the field electrode secured to the insulating nozzle follows the full stroke (travel) of the contact pieces; that means that in the ON position, the field electrode is inserted relatively far into the fixed continuous-current contact piece, requiring a corresponding space. The movement of the second arcing contact piece is also linked to the full stroke of the driven contact pieces.
SUMMARY
An object of the present invention is to optimize the sequence of motion of the field electrode, while shortening its stroke, and optionally, to improve the interaction with a driving mechanism for the second arcing contact piece.
To achieve this objective, according to the present invention, the field electrode is displaceable by a gearing which is includes of a first coupling shank that is connected via the insulating nozzle to the driveable continuous-current contact piece and runs in the direction of the longitudinal axis of the circuit-breaker, of a second coupling shank that runs parallel to the first coupling shank and is connected to the field electrode, and of a lever that is attached to the first coupling shank in a manner allowing the lever to swivel, a pin being secured to the swivelling part of the lever, passing through its swivel plane, the second coupling shank being connected to the pin, and the pin engaging with a connecting link guide that is incorporated in a plate which is fixedly joined to the second continuous-current contact piece. The and the connecting link guide
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designed in such a way that its first section runs approximately parallel to the longitudinal direction of the first coupling shank and its second, curved section allows the pin to deflect in a direction perpendicular to the longitudinal axis of the circuit-breaker.
Such a gearing permits the field electrode to be moved separately and independently of the driveable arcing contact piece, so that the speed and the travel of the field electrode can be different from that of the first arcing contact piece, the characteristic of the displacement movement being selectively predefinable in the form of a speed profile.
The special feature of the gearing lies in the lever swing-mounted on the first coupling shank, together with the pin secured to the swivel arm of the lever and guided in a stationary connecting link guide. A first section of the connecting link guide runs in a direction nearly parallel to the longitudinal direction of the first coupling shank. In this area, the pin is moved along the connecting link guide during the movement of the first coupling shank, without the lever swinging out. It is only in the second section of the connecting link guide, which allows the pin to deflect in a direction perpendicular to the longitudinal direction in which the coupling shank is moved, that the lever swings out, and the pin moves, at least with one motion component, in a direction perpendicular to the longitudinal direction of the first coupling shank. In this manner, the motion component of the pin in a direction parallel to the longitudinal direction of the first coupling shank (longitudinal axis of the circuit-breaker) is slowed down and finally stops, the lever further swinging through and the pin only moving in a direction perpendicular to the longitudinal direction. Since the field electrode is coupled to the pin via the second coupling shank, the speed of the field electrode in a direction parallel to the longitudinal direction of the shank is reduced during this last phase of motion until it comes to a standstill.
Consequently, the connecting link guide allows the field electrode to be moved in the same direction as the first coupling shank but at a different speed and a variable transmission ratio. This continues until the pin and, with it, the field electrode no longer moves in the longitudinal direction, while the first coupling shank is moved further. Thus, during the breaking operation, the field electrode can initially be moved together with the first arcing contact piece at the beginning of the movement, however, can be stopped before the movement of the first arcing contact piece ends, i.e., the traveling distance of the field electrode is shortened compared to the traveling distance of the first arcing contact piece.
One advantageous embodiment of the present invention provides for the curved second section of the connecting link guide to have a first end area adjacent to the first section and running in the direction of the first section, and a second end area running in a direction nearly perpendicular to the first section. This design of the connecting link guide allows the field electrode to move at the same speed as the first coupling shank as long as the pin is in the first section of the connecting link guide, and to slow down while the pin is in the second section of the connecting link guide. The second section of the connecting link guide expediently faces the driveable arcing contact piece. Because of this, in response to a tension movement of the first coupling shank during the breaking operation of the circuit-breaker, the pin is moved in the second section of the connecting link guide toward the end of the breaking movement, so that the speed of the field electrode then decreases to a standstill.
In a further advantageous refinement of the present invention, the second coupling shank, attached to the field electrode, can be connected to a cross-member which is supported in a manner that it is displaceable in the direction of the longitudinal axis of the circuit-breaker, and which has a slit, running in a direction perpendicular to the longitudinal axis of the circuit-breaker, with whi
Dienemann Hold
Lehmann Volker
Marin Heiner
Donovan Lincoln
Kenyon & Kenyon
Siemens Aktiengeselleschaft
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