WO2001069630A1 - Release device for a power circuit breaker - Google Patents

Abstract

The invention relates to a release device for a power circuit breaker (1) which has contacts (20) that are arranged in a housing and can be separated by actuating a release shaft (2) of a switching-off device. A blow-out channel (6) that is allocated to the contacts is configured in the housing. A lever (10) that is rotatably mounted on the housing engages with the release shaft (2) and has a baffle surface (14) which is allocated to the blow-out channel (6) and displaces the lever (10) after a pressure impact has occurred in the blow-out channel (6), for actuating the release shaft (2).

Description

 TRIP DEVICE FOR A CIRCUIT BREAKER

The invention relates to a

Tripping device for a circuit breaker.

A circuit breaker is known from EP 0583 149 Bl, which is equipped with contacts for quick disconnection by electrodynamic repulsion in the event of a short circuit. In the case of the rapid shutdown, an arc is drawn between the contacts, which causes a rapid increase in pressure in the housing accommodating the contacts. In the known from the aforementioned publication

The circuit breaker has a pressure chamber connected to the housing, so that the pressure in the pressure chamber also rises when the arc is formed. The pressure chamber is closed with a displaceable piston from the surroundings, so that the piston is displaced by the pressure increase in the pressure chamber. The piston is operatively connected to a switch-off device, so that the circuit breaker is switched off by the pressure increase.

The design of a pressure chamber with a sealing and displaceable piston, however, requires a lot of construction work during manufacture. In addition, the pressure chamber and the piston require additional space, which increases the overall dimensions of the circuit breaker. Furthermore, when installing the Circuit breaker can easily cause tension in the housing, which can lead to jamming of the piston.

In contrast, there is a need for a tripping device for a circuit breaker that reliably enables the circuit breaker to be opened in response to a pressure surge with little construction effort.

This need is met with a trigger device with the features of claim 1.

With the invention, a tripping device for a circuit breaker is created, which has contacts arranged in a housing, which by actuating a tripping element

Switch-off device are separable. A blow-out channel assigned to the contacts is formed in the housing. A lever is operatively connected to the release link and has a storage surface which is assigned to the blow-out channel and which deflects the lever following a pressure surge in the blow-out channel to actuate the release link.

Advantageous embodiments of the invention are specified in the subclaims.

The invention is explained in more detail below on the basis of preferred exemplary embodiments with reference to the drawing. It shows: Figure 1 is a schematic perspective partial view of a first embodiment of the invention.

FIG. 2 shows a schematic side view of a section of the device according to FIG. 1 to explain the invention;

3 shows a schematic side view of a section of a second exemplary embodiment of the invention in the non-triggered state of the triggering device; and

Fig. 4 is a Fig. 3 corresponding view in the triggered state of the trigger device.

1 shows a partially sectioned perspective view of a first exemplary embodiment of the invention. Fig. 1 shows a housing which is assembled from two housing half-shells. The housing encloses a cavity in which the electrical elements of the circuit breaker are accommodated. The housing has various bearing points for elements to be stored, which will be explained later. In the following description, in general, mounted on the housing means that corresponding bearing journals, openings, etc. are formed on the housing. The housing is made of an insulating material, preferably a plastic. Fig. 1 also shows a contact carrier 22 in the housing with an attached thereto

Fixed contact 20 of the circuit breaker 1. A movable contact assigned to this fixed contact 20 is omitted here for the sake of clarity. The circular pole tracks of the movable contact designed as a rotatable contact bridge are formed in the housing wall and can be seen in FIG. 1. Furthermore, circular bearing openings are formed on the housing, which rotatably hold the rotatable contact bridge.

The switch 1 also has a trigger shaft 2 as the trigger member which is operatively connected to the movable contact in order to separate it from the fixed contact 20 during a triggering process. The circuit breaker has a disconnection device (not shown) which is operatively connected to the contact bridge. The shutdown device can be a key switch, a ratchet mechanism or the like. The switch-off device is operatively connected to the trigger shaft 2. If the release shaft 2 is actuated (rotated) in the release direction, the switch-off device rotates the contact bridge around the

Bearing points on the housing and separates the fixed contacts 20 and the movable contacts (not shown) from each other. This will break the circuit through the circuit breaker.

The tripping device also has a mechanism with which the contacts can be closed again after the circuit breaker has tripped and the cause of the tripping has been eliminated. The fixed contact 20 is an arc quenching chamber 4

(hereinafter referred to as quenching chamber) assigned. Starting from the quenching chamber 4 extends Blow-out duct 6 in Fig. 1 substantially parallel to the lower horizontal edge of the housing to the outside of the housing. The blow-out duct 6 is partially delimited by the walls of the housing and is formed on the side of the housing facing away from an operating side of the circuit breaker. The blow-out duct preferably opens at one end of the housing, so that a plurality of housings can be attached next to one another without mutually blocking the blow-out ducts. The function of the blow-out duct and the arc chamber will be explained later.

A first lever arm 8 of a lever 10 projects into the blow-out duct 6, and a storage surface 14 is formed on the end of the lever in the blow-out duct 6 that at least partially blocks the cross-section or cross-sectional area of the blow-out duct 6. The lever 10 is rotatably or pivotally mounted on the housing at a pivot point 80. A second lever arm 18 of the lever 10 is formed in one piece with the first lever arm 8 and has a driver 12 at its end remote from the pivot point 80. The driver 12 is arranged opposite a stop 16 and designed for a release process with the stop 16, which on the

Trigger shaft 2 is designed to come into contact and take it with you during a trigger movement. Due to the design as a driver 12, which acts on a stop 16 in the release direction of the release shaft 2, the release shaft 2 can move independently of the driver 12 in its release direction. Consequently, it is possible that the trigger shaft 2 can be actuated by another trigger member, without being influenced by the lever 10 (driver 12).

As can be seen further in Fig. 1, the lever arm 18 of the lever 10 is double, i.e. the lever arm 18 has an essentially U-shaped shape (in FIG. 1 an upside-down "U"). The ends of the legs of the "U" are rotatably held at the pivot points 80 aligned with one another, while the base of the "U" forms the rod-shaped driver 12. In Fig. 1, the legs of the U-shaped lever arm 18 are also curved in a C-shape, so that the point of engagement of the driver 12 with the stop 16 is offset relative to the pivot points 80 of the lever arm 18 in Fig. 1 to the right. 1 shows the rest position of the lever 10, the C-shaped curvature of the lever arm 18 aligning the rest position of the lever 10 in such a way that the storage surface 14 considerably narrows or almost closes the blow-out channel 6. It should be noted that the storage surface 14 is arranged essentially transversely to the direction of flow in the blow-out duct. The storage surface 14 can also be arranged outside the blow-out channel 6 in the vicinity of its opening into the environment. It is sufficient if the storage surface 14 can be subjected to a pressure surge in the blow-out duct 6.

In the present case, the rest position of the lever 10 according to FIG. 1 is due to the lever shape and the equilibrium ratios of the weight forces

Lever 10 set appropriately. The rest position can also be achieved by a resilient element (not shown) be ensured. This resilient element can be a helical spring as a tension or compression spring, a spring tongue on the housing or lever or just a simple molded tongue when the lever or the housing is injection molded. Furthermore, the lever 10 can also be designed such that it rests against the stop 16 of the trigger shaft with a small force both in the rest position and in the triggered position.

The mode of operation of the circuit breaker 1 is explained in more detail below on the basis of the illustration in FIG. 2. Fig. 2 shows the switch of FIG. 1 in a partial side view. As in FIG. 1, the movable contact or the contact bridge is omitted in FIG. 2 for the sake of clarity.

In the event of tripping, the movable contact (not shown) moves downward from the fixed contact 20 in FIG. 2 by electrodynamic repulsion. The electrodynamic repulsion takes place through the magnetic fields around the contact carrier 22 (lower horizontal section) and the contact bridge (not shown) arranged parallel to the contact carrier 22 when the fixed contact 20 and the movable contact (not shown) on the contact bridge are closed. If a high current flows through the circuit breaker, current flows through two parallel conductors (contact holder and contact bridge) in the opposite direction. Magnetic fields of the same direction develop around the conductors and repel each other. If the current is high, the Magnetic fields so strong that they push the contacts apart against the closing force of the contacts. The closing force is applied by a spring mechanism. The arc spanned between the movable contact (not shown) and the fixed contact 20 during the separation produces a very rapid pressure rise (approx. 0.5 ms) of the air in the arcing chamber 4. This increase in pressure generates a pressure wave that propagates through the blow-out channel 6. The blow-out duct 6 is connected to the surroundings in order to release the pressure into the surroundings in the form of the pressure wave.

As it moves through the blow-out channel 6, the very fast pressure wave strikes the storage surface 14, which narrows the cross-section of the blow-out channel 6. The storage area 14 gives way due to the resulting back pressure, i.e. due to the pressure difference on the front and rear of the storage area, towards the environmental end of the

Blow-out channel 6 from (to the right in Fig. 2). As a result of this evasive movement of the storage surface 14, the lever 10, on the first lever arm 8 of which the storage surface 14 is arranged, is pivoted to the right in FIG. 2.

It should be noted that it is sufficient if the storage surface 14 is exposed to the pressure wave, i.e. no seal between the storage surface 14 and the blow-out duct 6 is required. The deflection of the storage surface 14 takes place essentially by

Conversion of the kinetic energy of the pressure wave into the dynamic pressure at the damming surface 14. With others Words, the deflection of the lever through the storage surface takes place dynamically. An arrangement of the storage area 14 in the blow-out channel 6 can further increase the effect of the storage area 14 because the pressure wave is better directed onto the storage area.

The lever 10 rotates counterclockwise in Fig. 2 about its pivot point 80 on the housing. The second lever arm 18 on the other side of the pivot point 80 pivots to the left in FIG. 2. The driver 12, which is arranged at the end of the second lever arm 18, presses against the peg-shaped stop 16 of the release shaft 2 and thereby rotates it in the release direction. This will trip the circuit breaker, i.e. the movable contact (not shown) and the fixed contact 20 are further separated from one another and electrically separated by rotating the contact bridge through the switch-off device, such as a key switch, a ratchet mechanism or the like. In other words, the

Arc between the contacts breaks off and extinguishes in the quenching chamber 4.

As can be clearly seen from FIG. 2, the length ratios of the first lever arm 8 and the second lever arm 18 are selected such that a deflection of the first lever arm 8 with a small force causes a deflection of the second lever arm 18 with a large force. More specifically, the first lever arm 8 is significantly longer than the second lever arm 18. This allows a force to be applied to the trigger shaft 2 by the driver 12 reliably sufficient for triggering the circuit breaker. The lever paths of the first and second lever arms are inversely related to the lever forces. The pressure wave propagates through the blow-out channel 6 with almost the same force, so that the accumulation surface 14 is always subjected to the differential pressure over the longer lever path of the first lever arm 8 and can accordingly generate the greater force on the second lever arm 18 without problems.

It should be noted that a lever 10 with a storage area 14 can be assigned to each blow-out channel of the switch. In particular in the case of multi-pole circuit breakers, this can be achieved with individual levers with a storage area in each case in one blow-out channel of each pole. Alternatively, a single lever can be connected to a plurality of storage areas, each of which is assigned to a blow-out channel. The individual storage areas can be connected to one another, for example, by means of suitable slot openings in the side faces of the blow-out ducts. A simple solution is also the arrangement of a lever with several storage areas at the respective surrounding openings of the blow-out channels, i.e. simply a storage area at the end of each blow-out channel. This can simplify the design of the lever, the connection of the storage area and the design of the blow-out channels. If necessary, the storage areas as the

Flaps that close the outlet channels can be designed, which can prevent the penetration of foreign materials. Another embodiment of the invention will now be explained with reference to FIGS. 3 and 4. Elements having the same effect as in FIGS. 1 and 2 are denoted by the same reference symbols, so that these elements are not explained again.

This exemplary embodiment differs from the previous exemplary embodiment in particular in the arrangement of the storage surface and the lever arrangement for transmitting force to the trigger shaft as the trigger member, so that the deviations from the first exemplary embodiment are described here in the main.

3 shows a side view of a portion of a circuit breaker in the non-tripped state, while FIG. 4 shows the same view in the tripped state of the circuit breaker.

3 shows an arcing chamber which is assigned to a contact pair (not shown). The quenching chamber is connected to the surroundings via a blow-out duct 6. A storage surface 14 is arranged in the blow-out duct 6 and is connected to a rotatable shaft 80. A lever extension 18 arranged on the shaft 80 forms a second lever arm 18 of a lever 10, the first lever arm of which is formed by the storage surface 14.

The second lever arm 18 engages with a first rocker arm 108 of a rocker arm 100 via a hinge 110. The rocker arm 100 is in one Pivot 800 is rotatably attached to the housing. The hinge 110 is designed such that a rotation of the lever 10 clockwise around the shaft 80 causes a rotation of the rocker arm 100 in a counterclockwise direction around the pivot point 800. The same applies to the reversal of the directions of rotation.

The rocker arm 100 has on its second rocker arm 118 a driver 12 which can interact with an associated stop 16 of the tripping shaft 2 in order to trip the circuit breaker. The engagement between the driver 12 and the stop 16 takes place analogously to the first exemplary embodiment, so that there is no repetition here.

If a pressure wave is generated in the blow-out channel 6 by an arc between the contacts (cf. explanations of FIG. 2), the storage surface 14 in FIG. 3 is pressed to the right. The storage surface 14 rotates the shaft 80 and the attached second lever arm 18 of the lever 10 also to the right (clockwise). By the engagement of the second lever arm 18 with the first rocker arm

108 by the hinge 110, the rocker arm 100 is rotated counterclockwise about the pivot point 800. The second rocker arm 118 swivels to the left and the driver 12 rotates the trigger shaft 2 in the triggering direction via the stop 16 and triggers the switch-off device. The end positions of the levers in the released state are shown in Fig. 4. The hinge 110 and / or the engagement between the driver 12 and the stop 16 can be designed such that the two levers 10 and 100 remain in the tripping position when the circuit breaker has been triggered by the pressure wave. As a result, this triggering case can be made easily visible on the housing by means of appropriate labeling (color marking, viewing window or the like).

Furthermore, the hinge can be formed not only by a lever end received between two pins, but also, for example, by a film hinge, which is used in the injection molding of lever 10 and

Rocker arm 100 is formed.

Here, too, the lever ratios are selected so that a sufficient triggering force is generated on the driver 12 of the rocker arm 100.

The embodiment shown in FIG. 3 or FIG. 4 is particularly suitable for multi-pole circuit breakers which have a plurality of blow-out channels in accordance with the number of poles. The rotary shaft 80 can be used to connect a plurality of storage surfaces in or on the individual blow-out ducts by guiding the rotary shaft through bores in the side walls of the respective blow-out ducts. This results in a simple mounting of the rotary shaft and a relatively good sealing of the individual exhaust ducts from one another, so that an effective pressure wave can be maintained in each of the exhaust ducts. By connecting all the storage areas with just one rocker arm, which can trigger a common disconnection of all poles of the circuit breaker, a simple construction is possible with which the circuit breaker can be triggered very quickly if a short circuit occurs at only one pole.

It should be noted that in this embodiment, too, the storage areas can be arranged at the ends of the blow-out channels and / or outside of them, as was explained above with reference to FIG. 1.

Claims

1. tripping device for a circuit breaker (1) with contacts (20) arranged in a housing, which can be separated by actuating a tripping element (2) of a disconnection device, with a blow-out channel (6) formed in the housing and assigned to the contacts (20), a lever (10), which is operatively connected to the release member (2), and a storage surface (14) formed on the lever (10), which is assigned to the blow-out channel (6), and the lever (10) a pressure surge in the blow-out channel (6 ) then deflects to actuate the release link (2). 2. Trigger device according to claim 1, characterized in that the lever (10) is rotatably arranged on the housing. 3. Trigger device according to claim 1 or 2, characterized in that the lever (10) has a plurality of storage surfaces (14), each of which is assigned to a blow-out channel (6). 4. Tripping device according to claim 1, 2 or 3, characterized in that the lever (10) with the trigger shaft (2) via a driver mechanism (12, 16) is operatively connected, which allows the triggering element (2) to be moved independently of the lever (10). 5. Trigger device according to claim 4, characterized in that the driver mechanism has a stop (16) to be acted upon in the trigger direction of the trigger member (2). 6. trigger device according to claim 1 to 5, characterized in that the storage-side lever arm (8) of the lever (10) is substantially longer than the trigger arm lever arm (18). 7. trigger device according to claim 1 to 5, characterized in that the lever (10) is mounted in the region of the blow-out channel (6) and with a rocker arm (100) rotatably mounted in the vicinity of the trigger element (2). 8. Trigger device according to claim 7, characterized in that the lever (10) and the rocker arm (100) are connected via a hinge (110) which holds the lever (10) and the rocker arm (100) in their respective end positions. 9. trigger device according to claim 1 to 7, characterized characterized in that the lever (10) is operatively connected to a resilient element which biases the lever (10) into a rest position. 10. Tripping device according to claim 7, characterized in that the storage surface (14) essentially forms the one lever arm of the lever (10). 11. Tripping device according to claim 10, characterized in that a plurality of storage surfaces (14) in a plurality of blow-out channels (6) are attached to a common rotatably mounted shaft (80) which forms the fulcrum of the lever (10). 12. Tripping device according to claim 1 to 10, characterized in that the storage surface is arranged opposite an outlet opening of the associated blow-out channel and outside the blow-out channel. 13. Tripping device according to one of the preceding claims, characterized in that the blow-out duct (6) is connected to an arc quenching chamber (4). 14. Tripping device according to one of the preceding claims, characterized in that the pressure surge is generated by an arc drawn during the electrodynamic repulsion between the separable contacts.