EP1047091B1 - Fuse particularly high power fuse - Google Patents

Abstract

The fuse has at least one melting conductor a mechanism for mechanically breaking it and an arrangement for triggering the mechanical breaking mechanism. The triggering arrangement contains at least one pressure capsule (20).

Description

The invention relates to a fuse, in particular a high-performance fuse, with at least one fusible conductor, mechanical means Cutting the fusible conductor and mechanical means for triggering the mechanical severing. Such fuses are preferred used in the medium voltage range, although they are in professional circles High-voltage fuses or high-voltage high-performance fuses to be named.

A fuse is used to connect a circuit to one or more their parts designed for this purpose, the circuit in which it is inserted, to interrupt. As the circuit parts separating fused conductors be provided or melt inserts are used, which interrupt the circuit by melting when a current exceeds a given value for a sufficiently long period of time.

High-voltage high-performance fuses (HH fuses) usually made of a ceramic tube body, at its ends provided with conductive contact caps. Inside the tube body are mounted on a ceramic insulator fusible link which electrically connected to the contact caps. The whole The fusible link structure is embedded in a quartz sand pad, which is the Cooling or clearing a fuse when the fuse is activated Arc serves. Et al this is the high performance behavior reached the fuses.

HH fuses have a current-limiting and selective effect and dissolve Melting of the fusible conductor automatically. They will in particular for the protection of equipment, preferably in medium voltage networks energy supply companies and industry.

A fuse of the type mentioned is known from US 4,369,420 or DE 196 07 756 C1 known, with a current safely and detectably interrupted can be provided by means according to the preamble of claim 1 for mechanically separating the Schmelzeiters are.

The locking device is to release the energy storage either by a thermal or an electrical guard, in parallel are connected to the fuse element and interact with it, triggered. The electrical monitor reacts to short-circuit currents, while the thermal guard against one over a certain Period of continuous overload secures.

Through the interaction of thermal and electrical guard a full-range backup is provided that covers all streams, which brings them to the response, up to the design value "Greatest Breaking current "safely and verifiably interrupts Fuse only occasionally triggered by melting. In this respect, the term fused conductor applies only conditionally, since the triggering of Fuse with overcurrents not only on the principle of melting through of the fusible conductor is limited, but additionally one deliberately induced mechanical separation of the same fusible conductor is initiated.

An inexpensive constructive embodiment of this backup will in DE 197 02 780 described. The separating rod is a shear rod educated. The shear rod is pivotable over one at one end mounted lever arm, which acts on a compression spring, in the direction of his Longitudinal axis drivable.

The lever arm is counter to the force of the compression spring by a retaining wire held around the lever arm. The one end of the retaining wire is held by a selective solder joint, which is the Function of the thermal guard has. The other end of the retaining wire is connected to a resistance wire.

The retaining wire gives the lever arm either in the case of a thermal Release free when the solder joint under the influence of small Overflowing resulting heat melts, or in the case of an electrical Tripping when due to the voltage drop at the first occurring Melting arcs within the fusible conductor a current shift takes place on the resistance wire, the latter to melt through brings. This version may be in one of the contact caps be housed in the tubular body of the fuse.

The present invention is based on the object, the aforementioned Fuse, in particular those known from US 4,369,420 High-voltage high-performance fuse, so to further develop that the functional effectiveness and the spatial allocation of the components is optimized, without requiring additional space results.

This object is achieved in that the means for triggering the mechanical Cutting through a pressure capsule include. The pressure capsule acts in such a way that when released triggers gas under pressure releases. This pressure acts on the means for mechanical severing of the fusible conductor so that the latter are also moved abruptly with the consequence that the fusible conductor ruptured and the circuit thus safely interrupted.

The pressure capsule can be designed in particular as a gas generator and, for example, a propellant charge or a pyrotechnic charge exhibit. But it is also a gas cartridge conceivable, the gas under contains very high pressure, which releases with release of the pressure capsule and then act on the means for mechanical severing can.

By using a pressure capsule can in particular to the use of comparatively strong springs, previously used to apply the necessary Forces used for mechanical cutting of the fusible link were waived. Also can about a pressure capsule a much greater force than generated by the springs. From this results in the possibility of the means of triggering the mechanical Separating and the means for mechanical cutting more compact perform as it was previously possible. So can easily a Full-range backup for all HH fuses, their design types and Dimensions are standardized in DIN 43 625, realized.

The pressure capsule is triggered mechanically.

The mechanical release has means to trigger the mechanical severing pure locking mechanism on, which ensures that the triggering of the pressure capsule in the normal Operating state does not occur, but only when a condition to trigger the fuse is given.

In principle, it is possible to trigger mechanically with a lever mechanism to realize its lever via a power storage, in particular via a spring, is biased and its pivoting in one degree of freedom through the locking mechanism until the time of the fuse is blocked. Once the lever is released is, the lever can act on the pressure capsule, for example by a blow to a firing plate the pressure capsule a spark produce.

In a preferred embodiment, such a lever is in his pivotally mounted middle portion, with a free arm in the operating state against a spring force of a retaining wire in blocking position is held and the other free end of the lever to trigger the mechanical severing acts on the pressure capsule. At this constructive design in the manner of a rocker, the individual Components are arranged in extremely compact form.

In another particularly preferred embodiment, the release means one in the direction of the pressure capsule movably mounted stamp on. The stamp is in the operating state by at least one blocking element held against a spring force and of this when triggered Approved. In contrast to the previously described lever mechanism Here is the stamp as the pressure capsule triggering element moved in a straight line instead of swinging. This in operating condition Locking element necessary to hold the punch can be a simple one Be a bolt.

This embodiment can be carried out particularly space-saving be that the blocking element cooperates with a locking bush, which surrounds the stamp, with the locking bush on its inner wall Has at least one recess which releases when triggered is, whereby the blocking element releases the punch. in this connection it is important that the blocking element is mounted so that it in the escape to release the pressure capsule released recess can.

The blocking element may preferably be formed as a detent ball which in one substantially perpendicular to the direction of movement of the punch Level is movably mounted. The locking bushing is in the operating state held by a retaining wire against a spring force, so that the Detent ball from the inner wall of the locking bush in a groove of the punch is held, and wherein the recess of the locking sleeve when triggered is displaced in the plane of movement of the detent ball. To trigger is the detent ball by the voltage applied to the punch spring force in pressed the recess so that it no longer blocks the stamp.

The means for triggering the mechanical severing include Advantageously, an electrical release, in particular from a Trigger wire exists. In case of overcurrent is caused by the or the arcs occurring on the fusible conductor of the current in such shifts the trigger wire that this melts. Is the trigger wire as Holding wire formed or connected to the retaining wire is thereby the held element free, so that the mechanical cutting of the fusible conductor is triggered.

Likewise, the release means of a thermal release, in particular consist of a selective solder joint. The selective solder joint melts due to continuous overload and not dissipated heat, so that this gives an effective overload protection is.

Especially if both the thermal and the electrical release act on one end of the retaining wire, is the retaining wire both held in an overload as well as a short circuit Element free. In this way, the backup acts as a full-range backup.

The means for mechanical cutting of the melt insert have prefers a shear bar with at least one groove into which or engage the fusible link, the shear rod in the direction of his Longitudinal axis is movably mounted and with one or the fusible link holding fusible conductor carrier cooperates. When triggered the Pressure capsule, the shear rod namely abruptly relative to Fusible conductor carrier moves, so that in the fuse carrier and the shearing rod engaging fusible link is torn. This will the fusible conductor destroyed so that another by a Electricity generated arc is safe to exclude.

In this case, the pressure capsule facing the end of the shear rod in be led by a recording and an expansion chamber with the Pressure capsule communicate. Especially in combination with the working with a punch locking mechanism results in the Advantage that the ignition mechanism for the pressure capsule, the pressure capsule itself, the expansion space and the shear bar along an axis, in particular be arranged along the longitudinal axis of the fuse can.

The separation effect can be especially for small size fuses be improved by the fact that the fuse carrier in Direction of its longitudinal axis is movably mounted and when triggered the means for mechanical severing in the direction of movement the shear rod opposite direction is moved. For this can the fuse carrier against a spring force from a locking device be held at the time of release of the pressure capsule releases the fuse carrier.

The fuse may preferably be a display element for displaying the triggered condition of the fuse, so that the respective state the fuse is visible. With the display element can also at corresponding embodiment an outside of the fuse befindlicher Switch-disconnector can be actuated.

The display element can in particular be connected to the blocking bushing be. For this purpose, a hook for the engagement of the Retaining wire be provided so that the locking bush through the display element is held in its blocking position in the operating state. at In another embodiment, the display element can be moved arranged Schmelzleiterträger connected to the fuse carrier be, optionally also a part of the fuse carrier be.

Finally, it can be seen from the foregoing Possibility of a compact design can be used to all Means for initiating mechanical severing in one of the contact caps the fuse are arranged.

Further details and advantages of the invention will be described below the description of preferred, in the accompanying drawings illustrated embodiments explained in more detail.

Fig. 1

das Prinzip einer aus der DE 197 02 780 vorbekannten Ganzbereichsicherung;

Fig. 2

eine Ausführungsform der Sicherung mit einem Hebelmechanismus in Betriebsstellung, im Längsschnitt;

Fig. 3

die Ausführungsform gemäß Fig. 2 in ausgelöstem Zustand, im Längsschnitt; und

Fig. 4

eine andere Ausführungsform der Sicherung ohne Hebelmechanismus, im Längsschnitt.

Show it:

Fig. 1

the principle of a previously known from DE 197 02 780 full-range backup;

Fig. 2

an embodiment of the fuse with a lever mechanism in the operating position, in longitudinal section;

Fig. 3

the embodiment of Figure 2 in the triggered state, in longitudinal section. and

Fig. 4

another embodiment of the fuse without lever mechanism, in longitudinal section.

In Figure 1, the principle of a known from DE 197 02 780 C1 High performance assurance demonstrated, based on the operation of such Fuses will be explained in more detail below. The interrupted in the middle area illustrated fuse 101 has a standard design on and consists of a cylindrical, with quartz sand filled safety body 102, the front side, each with a contact cap 103, 104 is provided. At each end face of the safety body 102 is in the respective contact cap 103, 104 a sheet metal cover 105, 106th provided, which prevents leakage of quartz sand.

To simplify the illustration are known per se, in quartz sand embedded and usually on a ceramic insulator wound melt wires not shown, especially as this Expert in the art and in the aforementioned DE 196 07 756 C1 is shown.

The aforementioned means for mechanical severing have a Shear rod 107, which in the event of triggering in the direction of its longitudinal axis moved abruptly, while the guided through its slots Melting conductor severed. For this purpose, the rod is mechanically biased to pressure, wherein the energy accumulator consists of a spring 108, the over a pivotally mounted receiving plate 109 at the lower end of the Shear Staff 107 attacks. The energy storage is within the lower one Contact cap 104 of the fuse arranged.

Within the opposite contact cap 103 is the shear bar 107 via a locking lock 110 in an operating position against the spring force held on a first pivotally mounted Lever 111 is hinged, the free end of the free end of a second pivotable lever 112 secured against pivoting can be. The second lever 112 can both via a thermal Watchdog 113 as well as an electrical guard 114 in its operating position being held. The thermal guard 113 can do this be formed by a selective solder joint, while the electric Guardian 114 receives its function through a resistance wire 115, wherein the resistance wire 115 is connected via a node 116 to one end a holding wire 117 holding the lock in operating position holding connected is and the other end of the retaining wire 117 in the selective solder joint 113 is inserted.

The illustrated in Figure 2 embodiment of an inventive Backup, for the sake of clarity only the means shown to trigger the mechanical severing end is has a tubular body 1 made of a ceramic material on. In the tubular body 1 is inter alia a fusible link in quartz sand embedded, wherein the fusible conductor on a fuse carrier is wound up. The fuse holder is an elongated body a ceramic material with a star-shaped cross-section. Of the Melt conductor is electrically connected to the contact caps.

The ends of the tubular body 1 are closed, each with a contact cap 2. The interior of each contact cap 2 is provided with a metal cover 3 opposite the pipe body completed to a discharge to prevent the quartz sand located in the tubular body. The the fuse final outside of the contact cap 2 is with a Öff 4 for a display or release pin 5 provided.

In the contact cap is a rocker 6 as a lever mechanism, which is mounted pivotably about a pivot point 7. The display and Release pin 5 is by means of a compression spring 8 in the longitudinal direction of the Tubular body 1 applied to the end of the fuse directed towards spring force and engages one of the two lever arms 9, 10 of the rocker 6. This lever arm 9 is against the spring force of a retaining wire 11 held in a locked position, in a loop around the lever arm 9 is guided. To the lever arm 9 during assembly of the To hold fuse in this blocking position is a bore 12 for a Mounting fuse provided.

The retaining wire 11 is on the one side at a junction 13th held by a knot. In the field of knotting is the Holding wire 11 formed as a resistance wire. The other end is in Area of the joint 13 soldered to a selective solder. Of the Holding wire 11 is electrically connected in parallel to the fuse element. The Junction 13 is connected to the sheet metal cover 3, wherein about seals 14, 15 made of plastic both a spatial seal towards the interior of the contact cap 2 as well as an electrical Insulation against the sheet metal cover 3 is guaranteed. With this Formation of the retaining wire 11, as discussed above, both a Overload protection and protection against short circuits guaranteed.

As FIG. 3 shows in particular, the other lever arm 10 of the rocker 6 aligned so that it can trigger a pressure capsule 16 by opening a firing pin 17 strikes, as soon as the lever arm 9 from the retaining wire 11th is released. The rocker 6 is in this case of the prestressed display and release pin 5 pivoted, with part of the display and Release pin 5 exits through the opening 4 in the contact cap 2. Thereby on the one hand the triggering of the backup is indicated, on the other hand can by the display and release pin 5, a switch for switching off actuated further phases or downstream operating devices become.

The pressure capsule 16 has a receptacle for a shear bar 18, the in the figures 2 and 3 for reasons of clarity not accurate is shown. The shear rod 18 is replaced by that of the pressure capsule 16th generated gas pressure abruptly parallel to the longitudinal axis of the fuse moved away from the pressure capsule 16, so that in the shear rod 18th and the fusible link carrier engaging fusible link breaks.

This results from the previously known with reference to Figure 1 Securing the advantage that on a spring in the lower contact cap can be omitted, since the shear rod 18 is not biased have to be.

To the relative speed between fuse carrier and shear bar 18, for example, facing away from the pressure capsule 16 End of the shear rod 18 may be provided a rocker, the Direction of the momentum of the shear bar 18 reverses and on the Fusion conductor carrier transfers.

The pressure capsule 16, the display and release pin 5 together with the compression spring 8, the rocker 6 and the junction 13 are shared by the Sheet metal cover 3 and a cup-shaped bushing 19 held so that they already pre-assembled in the contact cap 2 are fitted can.

The embodiment of the invention shown in FIG comes without a lever mechanism. Here is a pressure capsule 20 triggered via a plunger 21, which for this purpose a Zündstöpsel 22 depresses. The punch 21 is formed as a cylindrical body and in a hollow cylinder 23 in the direction of the ignition plug 22nd movably mounted. At the side facing away from the pressure capsule 20 of the Stamp 21 engages a first compression spring 24.

The punch 21 is in the operating position of detent balls 25 in the blocking position held, which engage in a circumferential groove 21 on the punch 42. At the same time, the locking balls 25 in openings provided for this purpose 26 held in the wall of the hollow cylinder 23. So that the locking balls 25 secured against falling out of the wall of the hollow cylinder 23 are, a locking bush 27 is provided, which the hollow cylinder 23 in Area of openings 26 completely surrounds. The locking balls 25 are thus secured in position by the inner wall of the locking bushing 27.

The locking bush 27 is in the direction of the longitudinal axis of the hollow cylinder 23rd movably mounted, wherein a spring 28, the locking sleeve 27 of the Pushes off pressure capsule 20. Against this spring force is the locking bush 27 held by a retaining wire 29, which at one with the locking bush 27 firmly connected indicator pin 30 attacks. The retaining wire 29th facing the end of the indicator pin is designed as a hook to the around the retaining wire 29 is guided.

Are the retaining wire 29, the indicator pin 30 and thus the locking sleeve 27th free, this shifts in the direction of force of the spring 28. This will Recesses 31 in the inner wall of the locking bush 27 in the area the openings 26 of the hollow cylinder 23 is moved. The detent balls 25 are by the standing under the force of the compression spring 24 Stamp 21 is pressed into the recesses 31, so that the punch 21 is no longer locked. So that the stamp 21 does not tip, he is on the way towards the ignition plug 22 by a second compression spring 32, which is arranged between pressure capsule 20 and punch 21, stabilized. The spring force of the compression spring 32 is substantially lower than that of the compression spring 24.

The retaining wire 29 is the same as in the previously described embodiment with its one end in the form of a selective solder joint 33 in one for it provided solder socket 34 and with its other end by a Knotting 35 attached to a junction 36, the mode of action of the retaining wire 29 identical to the previously described is.

All of the aforementioned components of this embodiment are of a cup-shaped bushing 37, with its open side in the Contact cap 43 is pressed.

From Figure 4 it is clear how the shear bar 38 with the pressure capsule 20th communicates. For this purpose, the shear rod 38 is guided in a sleeve 39. In operation, the end of the shear rod 38 is located at a Rejuvenation 45 within the sleeve 39, which has a sufficient expansion chamber 40 between pressure capsule 20 and shear rod 38 guaranteed.

The shear bar 38 does not have on its outside for engagement from here shown fusible links 41 slots.

Claims (21)

1. Fuse, in particular a high-breaking-capacity fuse, having at least one fuse link, means for mechanical separation of the fuse link and means for actuation of the mechanical separation, which include a pressure capsule (16, 20),
   characterized by a mechanical actuation of the pressure capsule (16, 20) and by a locking mechanism for the means for actuation.
2. Fuse according to claim 1,
   characterized in that,
   the pressure capsule (16, 20) is a gas generator.
3. Fuse according to claim 1 or 2,
   characterized in that,
   the pressure capsule (16, 20) has a cartridge with a propellant charge and a pyrotechnical charge.
4. Fuse according to claim 3,
   characterized in that,
   the locking mechanism has a lever (9, 10), mounted pivotably in a middle region, which lever is, in the operating condition, held in a locking disposition by a retention wire (11) against a spring force, wherein the retention wire (11) engages at a free end of the lever (9, 10) and the other end acts upon the pressure capsule (16) for actuation of the separation.
5. Fuse according to claim 3 or 4,
   characterized in that,
   the means for actuation of the separation have a plunger (21), mounted moveably in the direction towards the pressure capsule (20), which plunger is, in the operating condition, held by at least one locking element against a spring force, and for actuation of the separation is released by this locking element.
6. Fuse according to claim 5,
   characterized in that,
   the locking element cooperates with a locking sleeve (27), which is arranged around the plunger (21), wherein the locking sleeve (27) has on its inner wall at least one recess (31) which, for actuation of the separation, is made free, through which the locking element unlocks the plunger (21).
7. Fuse according to claim 6,
   characterized by
   at least one latch ball (25) as locking element, which is mounted moveably in a plane substantially perpendicular to the direction of movement of the plunger (21), wherein the locking sleeve (27) is, in the operating condition, held by means of a retention wire (29) against a spring force, so that the latch ball (25) is held by the inner wall of the locking sleeve (27) in a groove (42) of the plunger (21), and upon actuation of the separation the recess (31) of the locking sleeve (27) is displaced into the movement plane of the latch ball (25).
8. Fuse according to any of claims 1 to 7,
   characterized in that,
   the means for actuation of the separation include an electric actuator in particular formed by means of a wire.
9. Fuse according to claim 8,
   characterized in that,
   the actuation wire constitutes the retention wire or is connected with the retention wire (11, 29).
10. Fuse according to any of claims 1 to 9,
    characterized in that,
    the means for actuation of the separation include a thermal actuator, in particular a selective solder point (33).
11. Fuse according to claim 10,
    characterized in that,
    the thermal actuator acts upon the retention wire (11, 29).
12. Fuse according to any of claims 1 to 11,
    characterized in that,
    the means for separation of the fuse link comprise a shearing rod (18, 38) having at least one groove into which the fuse element or elements engage, wherein the shearing rod (18, 38) is mounted moveably in the direction of its longitudinal axis and stands in working connection with a fuse element carrier holding the fuse element or elements.
13. Fuse according to claim 12,
    characterized in that,
    the shearing rod (18, 38) can be acted upon directly by the pressure capsule.
14. Fuse according to claim 12 or 13,
    characterized in that,
    the end of the shearing rod (18, 38) towards the pressure capsule (16, 20) is guided in a receiving part and stands in connection with the pressure capsule (16, 20) via an expansion chamber (40).
15. Fuse according to any of claims 12 to 14,
    characterized in that,
    the fuse element carrier is mounted moveably in the direction of its longitudinal axis and upon actuation of the means for separation is moved in a direction opposite to the direction of movement of the shearing rod (18, 38).
16. Fuse according to any of claims 1 to 15,
    characterized by
    an element (indicator/impact pin) for indicating the actuated condition of the fuse.
17. Fuse according to claim 16,
    characterized in that,
    a load separation switch located outside the fuse can be actuated with the indicator element.
18. Fuse according to claim 5 or 6 and/or according to claim 16 or 17,
    characterized in that,
    the indicator element is connected with the locking sleeve (27).
19. Fuse according to claim 18,
    characterized in that,
    the locking sleeve (27) is, in the operating condition, held via the indicator element in a locking disposition and the indicator element is held by the retention wire (29).
20. Fuse according to any of claims 15 to 17,
    characterized in that,
    the indicator element is connected with the fuse element carrier.
21. Fuse according to any preceding claim,
    characterized in that,
    the means for actuation of the separation are arranged in one of the contact caps of the fuse.

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