Signaling device for indicating a tripped state of a short-circuiting device

Abstract

Signaling device for signaling a tripped state of a short-circuiting device which can be brought into a short-circuit position by means of an explosively generated gas flow, wherein a pressure relief channel (6) is provided in the short-circuiting device (1) through which an overpressure generated by the gas flow is relieved, wherein the pressure relief channel (6) has an outlet opening (7) which leads to an application point (16) on a signaling plunger (10), wherein the signaling plunger (10) is movably guided between a normal position and a signaling position, and the signaling position can be assumed after being acted upon by the gas flow, wherein the signaling position is generated after being acted upon by the gas flow by force exerted by a spring which is mounted in tension in the normal position.

Description

The invention relates to a signaling device for signaling a triggered state of a short-circuiting device which can be transferred into a short-circuiting position by means of an explosively generated gas stream, wherein a pressure relief channel is present, by means of which a positive pressure generated by the explosion is reduced.Such short-circuiting devices are operated with a pyrotechnically operating gas generator and are known, for example, from DE 197 46 564 A1. These short-circuiting devices are mainly used in arcing fault protection devices, which can be taken, for example, from DE 199 16 327 A1 or from DE 197 12 387 A1. The essential function of such arcing fault protection devices is to eliminate high arc currents in the earliest phase of their development in the event of a short circuit and associated with harmful consequences. The most effective measure is to switch off the system current in the shortest possible time and / or to short-circuit the live phases between which the arc was ignited, whereby the arc is immediately extinguished.The document DE 197 12 387 A1 describes a pyrotechnic switching element in which a pyrotechnic charge is used to move a bridging element such that the bridging element connects a first conductor and a second conductor in a first state and connects the second conductor to a third conductor in a second state.GB 1 321 381 A describes a switch by means of which a connection between conductors can be produced by applying a suitable signal, a bolt being brought into a gap between the conductors by triggering a detonator.Disadvantages of the Prior ArtIn the aforementioned devices, there is no possibility of signaling the activated or deactivated (short-circuited) state to the outside or of transmitting a status message to the remote with auxiliary switches. It cannot be seen from the outside on the devices whether the short-circuiting device is activated and short-circuited. The state of the device can only be investigated with difficulty after the device has been removed from the switchgear cabinet. The assessment of the state requires reliable knowledge about the structure and function of the short-circuiting device. The user (customer) is forced to check, for example with a measuring device, whether a short circuit has been generated (whether there is a connection of the individual phases).DE 197 12 387 A1 describes a closure plug of the gas generator which is destroyed and ejected by the internal pressure. Using the ejection of the plug as an indication is a technical inadequate solution, since the loose plug may fly into the plant in an uncontrolled manner and damage the plant.Meanwhile, according to a North American specification (UL 2748), it is required that a visually recognizable visual display is to be present on a short-circuiting device for a arcing fault protection device, which visual display makes the short-circuiting switching process visible.It is the object of the invention to specify a signaling device for signaling a trip state of a short-circuiting device which indicates the short-circuiting switching process that has taken place directly and reliably.The solution of the object is found in the features of the main claim, further and preferred embodiments are formulated in dependent claims.In particular, the object is achieved by means of a signaling device for signaling a triggered state of a short-circuiting device which can be transferred into a short-circuit position by means of an explosively generated gas stream. In the short-circuiting device, a pressure relief channel is present, through which an overpressure generated with the gas flow is reduced, wherein the pressure relief channel has an outlet opening, which leads to an engagement point (16) on a signaling plunger. The signaling plunger (10) is guided movably between a normal position and a signaling position, and the signaling position can be taken in after the gas stream has been acted on, wherein the signaling position is generated after the gas stream has been acted on by the force unfolding of a spring which is mounted such that it is tensioned in the normal position.The essential core of the invention is that the activation of the short-circuiting device is signaled by a signaling plunger.A simple and effective activation of the signaling device consists in the direct use of the overpressure generated by the gas generator in the pressure relief channel. The overpressure actuates the signaling plunger via an engagement point present on the signaling plunger. A rebound or the return of the normal position of the signaling plunger is prevented by a blocking mechanism.Advantages of the invention lie in the simple construction of a signaling plunger, it being possible to meet regulations for the North American market.The description of the invention and preferred embodiments are explained below. Preferred embodiments of the invention can be realized individually or-insofar as technically expedient-in combination with one another.The signaling plunger consists of an electrically non-conductive plastic part which can be manufactured cost-effectively. The signaling plunger is cylindrical, wherein the signaling plunger is securely mounted in the device in an axially parallel manner with respect to the short-circuiting device and is prevented from moving in the normal position by a latching element. A mounting carried out in the locking position also has the advantage that the signaling plunger cannot be moved out of its normal position due to vibrations occurring during industrial operation. As a result of the gas flow, the signaling plunger can be moved over a release surface or a latching element until a prestressed spring is released. The latching element or the unlatching surface can be formed on the short-circuiting device.The signaling device is designed such that the signaling position can be displayed optically and / or electrically. For the optical signaling of the activated state, the signaling plunger or a leg present on the signaling plunger protrudes out of the device housing.The signaling plunger can be transferred into the signaling position by a rotational movement, by a lifting movement or by a rotational-lifting movement. The signaling position is generated by the development of force by a spring which is mounted such that it is tensioned in the normal position.At least one laterally protruding leg is formed on the signaling plunger. The at least one leg is directed against the exit opening and its front end covers the exit opening. The triggering of the signaling plunger takes place via the pressure relief channel, by means of which the overpressure is reduced after the ignition of the gas generator and the actuation of the short-circuiting element. The signaling plunger is moved via a latching element or a disengaging surface until a prestressed spring is released. This spring then moves the signaling plunger into the end position referred to as the signaling position. The activation of the short-circuiting device (triggering display) is optically signaled by the protrusion of the signaling plunger from the housing and can be additionally signaled electrically by activating an auxiliary switch.A second leg may be formed on the signaling plunger, which leg is directed in the direction of at least one auxiliary switch, wherein the second leg is configured to actuate the at least one auxiliary switch in the signaling position.The auxiliary switches are inserted into a housing opening and fastened there. A stroke of the signaling plunger generated by a compression spring after it has been triggered by a gas jet moves the signaling plunger in the direction of the switching plungers of the auxiliary switches and switches the contacts of the auxiliary switches.One auxiliary switch can be provided as a signal transmitter for the triggered state; the other auxiliary switch can be designed as a remote switching transmitter for a circuit breaker. As a result, remote signalling and locking of the feeding switch (usually circuit breakers) are possible directly from the short-circuiting device. After the short circuit produced by the short-circuiting device, the circuit breaker must be blocked against being switched on again until the arcing fault has been corrected and the short-circuiting device has been renewed.The signaling device can be designed such that in the signaling position of the signaling plunger only one optical message, only one electrical message or both types of messages takes place. The signaling according to the invention can be implemented with different embodiments.The signaling plunger should preferably not be able to be reset from its signaling position into the normal position. This is intended to prevent the position of the signaling plunger from being changed intentionally or unintentionally. Since the auxiliary switches were activated, a faulty position of the signaling plunger would impair the function of the signaling device.Short-circuiting devices with the indicated signaling device should preferably be integrated in a arcing fault protection device.A blocking mechanism is to be used to prevent the resetting. For this purpose, a mechanical baffle can be formed which the signaling plunger has to overcome during the movement into the signaling position and which makes a movement in the opposite direction impossible. The signaling plunger is blocked and held irreversibly in the position. The position of the signaling ram can no longer be reset to the original state (device not yet triggered) without destroying the baffle.Various technical solutions can be provided for restarting the short-circuiting device. A first solution is that the activated short-circuiting device is replaced by a new, functionally functional short-circuiting device. Another solution consists in the exchange of parts, wherein for example only the gas generator is removed and replaced by a new one which is functional. Furthermore, the insulating parts pierced by the bridging element must be replaced. Within the scope of the latter solution, the signaling plunger could also be used again, wherein it is brought into its normal position during assembly with the housing. As is still shown in detail in the description of the figures, the lower end of the signaling plunger is mounted in a sleeve. Inserted there is a compression spring located in the sleeve tensioned. The normal position is assumed in that the signaling plunger is latched behind a latching element on the short-circuiting device. When the housing is placed on, the signaling plunger is inserted into the cylindrical housing opening, where it finds a second bearing.The invention is illustrated in drawings, in which: FIG. 1 : shows a arcing fault protection device with a signaling plunger, illustrated in a cut-away appliance housing, FIGS. 2A, 2B, 2C : three views of a preferred signaling plunger, and FIG. 3 : shows a arcing fault protection device (as prior art) with a signaling plunger.FIG. 1 shows a short-circuiting device 1 for a arcing fault protection device, which is illustrated in a cut-open device housing 40 (cf. also FIG. 3 ). The central element is a gas generator 2, which can be activated via a pyrotechnic switching element. The protective device serves for short-circuiting at least two busbars, which are separated from one another by an insulating separating element 8', via a bridging element 3. As a result of the ignition of a pyrotechnic charge, the bridging element is accelerated explosively and, after the ignition of the pyrotechnic charge, is brought into a position in which at least two busbars (5.1, 5.2) are bridged. The short-circuiting device 1 is fastened above two busbars (5.1, 5.2) in insulated fashion via plastic elements 4, wherein one of the busbars 5.1 is visible. The bridging element penetrates from above into one opening each of the busbars and is keyed there. The pyrotechnic activation consists of an explosively generated gas stream, wherein a pressure relief channel 6 is present, through which the generated gas stream escapes.The protective device shown as a preferred arrangement in FIG. 1 is fastened to the busbars via an insulating lower part 8. The dimensions of the insulating subpart are essentially determined by the requirement for sufficient insulation distances of the live parts. The signaling device is mounted on the insulating lower part 8 The insulating lower part carries a sleeve 21 The signaling plunger 10, which is described in more detail and in detail in FIGS. 2A to 2C, is disposed with its lower end 12 parallel to the axis of the short-circuiting device 1 in the sleeve 21 A compression spring (not visible) is introduced in the sleeve 21, which compression spring is tensioned by the signaling plunger 10 in the normal position. The signaling plunger 10 lies with its upper end 13 in a cylindrically formed housing opening 42. In the normal position, the signaling plunger remains recessed within the housing opening 42 (approximately 1 to 2 mm deep). Two legs 14, 17 are formed on the signaling plunger, wherein the first leg 14 is directed toward the outlet opening of the pressure relief channel of the gas generator. The front end of the first leg 14 covers the outlet opening (not necessarily gas-tight). The position of the signaling plunger (and the tensioned position of the compression spring) is determined by a latching of the first leg 14 on a latching element 19. The latching element 19 is designed as an elastically yielding tongue on the insulating lower part 8. The signaling plunger can be moved from this first end position into the second end position (see reference sign Dr) when the pyrotechnic switching element is activated and the explosively generated gas flow exits from the outlet opening.According to the various embodiments of the invention, the signaling plunger 10 can be transferred into the second end position (signaling position) by a rotational movement, by a lifting movement or by a rotational-lifting movement. The embodiment shown in FIG. 1 shows the configuration in the manner of a rotational-stroke movement. See also FIG. 2B.The gas flow emerging explosively from the outlet opening 6 rotates the signaling plunger out of the latching position (release of the latching element). The tensioned compression spring in the sleeve 21 moves the signaling plunger in the axial direction with a stroke H by approximately 8 to 10 mm toward the housing opening 42, wherein the edge present at the transition from larger to smaller diameter of the upper end of the shaft abuts against the lower edge of the cylindrical bore 42. In the reporting or signaling position, the upper end of the reporting plunger protrudes out of the bore 42. To clearly visualize this position, the upper end of the signaling plunger or the signaling plunger as a whole can be colored in a signal color.FIGS. 2A, 2B, and 2C show the signaling plunger in one of the embodiments in three views. Embodiments are not shown in which no legs are present on the signaling plunger or only one leg is present on the signaling plunger or in which the legs have a different shape than shown. The signaling plunger is characterized by a simple design. It can be produced as an injection-molded part without complicated slides in the tool. The signaling plunger does not require precise guidance in the housing, since tight tolerances are not required. The signaling plunger 10 has essentially a cylindrical shaft 11, the upper 13 and lower 12 ends of which are tapered behind a step in diameter. According to the embodiment shown in the figures, two-approximately opposite-legs 14 and 17 are formed on the lower region of the shank 11.At the front end of the first leg 14, a closure dome 16 is formed. This is in the normal position of the outlet opening. The front end of the second leg 17 is designed to actuate the switching rams 32 of the auxiliary switches 30.1, 30.2. The switching edge 18 has a position of 90° with respect to the axis of the shaft of the signaling plunger (see also FIG. 1 ).FIG. 2C shows the signaling plunger 10 in a view from below onto its lower end. The two legs 14, 17 form an obtuse angle between 160° and 1754. At the front end of the first leg 14, a closure dome 16 can be seen, which covers the outlet opening 6 (not necessarily gas-tight).FIG. 3 shows a arcing fault protection device as prior art, in a position in which the metallic bridging element 3 has penetrated the insulating separating element 8' after explosion-like generation of the gas flow and is keyed in between the busbars 5.1, 5.2. The signaling plunger 10 according to the invention is shown. The signaling plunger still abuts the outlet opening 7. The figure shows: pyrotechnic gas generator 2; metallic bridging element 3; plastic elements 4; first busbar 5.1; second busbar 5.2; pressure relief channel 6; outlet opening 7; insulating lower part 8; signaling plunger 10; housing or hood 40.Reference numerals denote reference numerals1 Short-circuiting device 2 pyrotechnic gas generator 3 metallic bridging element 4 plastic elements 5.1 5.2 conductor rails 6 pressure relief channel 7 outlet opening 8 insulating lower part 8' insulating separating element 10 signaling plunger 11 shaft 12 end at the bottom, with stepped portion 13 end at the top, with stepped portion 14 first limb 15 front end 16 closure cap 17 second limb 18 switching edge 19 latching element 21 sleeve 30.1, 30.2 two auxiliary switches 32 switching plunger 40 housing, or hood 42 housing opening Dr rotational movement H lifting movement

Claims

Signalling device for signalling a triggered state of a short-circuiting device which can be transferred into a short-circuit position by means of an explosively generated gas stream, wherein a pressure relief channel (6) is present in the short-circuiting device (1), through which pressure relief channel an overpressure generated with the gas stream is reduced, wherein the pressure relief channel (6) has an outlet opening (7) which leads to an engagement point (16) on a signalling plunger (10), wherein the signalling plunger (10) is movably guided between a normal position and a signalling position, and the signalling position can be taken in after the gas stream has been acted on, wherein the signalling position is generated after the gas stream has been acted on by force unfolding of a spring which is mounted such that it is tensioned in the normal position.The signaling device according to claim 1, characterized in that the signaling device is designed such that the signaling position can be displayed optically and / or electrically.Signalling device according to Claim 1 or 2, characterized in that the signalling plunger (10) can be transferred into the signalling position by means of a rotary movement, by means of a lifting movement or by means of a rotary-lifting movement (Dr, H).Signalling device according to one of the preceding claims, characterized in that a return of the signalling plunger (10) from the signalling position into the normal position is prevented by a blocking mechanism.The signaling device according to any one of the preceding claims, characterized in that the signaling plunger (10) is cylindrical, wherein the signaling plunger (10) is mounted axially parallel to the short-circuiting device (1) and is prevented from moving in the normal position by a latching element (19).Signalling device according to Claim 5, characterized in that a first laterally projecting limb (14) is formed on the signalling plunger (10), and this limb (14) is directed towards the outlet opening (7) and the front end of the first limb (14), which is formed as an engagement point (16), covers the outlet opening (7).The signaling device according to claim 6, characterized in that a second leg (17) is formed on the signaling plunger (10), which leg is directed in the direction of at least one auxiliary switch (30.1, 30.2), wherein the second leg (17) is configured in the signaling position for actuating the at least one auxiliary switch (30.1, 30.2).Signaling device according to Claim 9, characterized in that one of the auxiliary switches (30.1) is designed as an electrical signal transmitter for the triggered state and the other auxiliary switch (30.2) is designed as a remote switching transmitter for a circuit breaker.Signalling device according to one of the preceding claims, characterized in that a short-circuiting device (1) equipped with a signalling device is integrated in a arcing fault protection device.

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