JPH04282527A - Network fuse element - Google Patents

Abstract

PURPOSE:To enlarge breaking performance with a wattage loss left small by decreasing breaking points connected in series at continuous electrification time, and increasing the breaking points connected in series by changing a current flow at breaking time. CONSTITUTION:At continuous electrification time, the same current flows in a series circuit of four series breaking points A1-B2-A3-B4 and in a series circuit of four series breaking points B1-A2-B3-A4. Here, no current flows in bridge breaking points C1, C2, C3. At breaking time, by designing A type breaking points A1 to A4 so as to fuse earlier than the breaking points B1 to B4, the A type series breaking points A1 to A4 are all fused with only the B type series breaking points left at breaking final time, so that the current flows to pass in series the seven breaking points B1-C1-B2-C2-B3-C3-B4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power fuse, and more particularly to a fuse with improved interrupting performance and reduced power dissipation during continuous energization.

0002

[Prior Art] A conventional fuse element has a plurality of (S
A plurality (P) of circuits each having ( ) breaking points connected in series were arranged in parallel to satisfy various performances given for various rated voltages and rated currents. A series circuit of P parallel interrupting points must have exactly the same electrical characteristics, but as disclosed in Japanese Patent Application Laid-Open No. 62-51128, it must be thermally conductive and electrically insulating. highly sexual,
For example, a highly accurate fuse element can be manufactured by a method such as forming a conductive metal film on a ceramic substrate and forming a fuse pattern using a photographic method.

FIG. 5 shows an example of a fuse pattern of the above-mentioned fuse element. This fuse is 660V, 6
This is an example for 0A, in which six cutoff points A0 are connected in series, and five circuits are connected in parallel. The electrical characteristics of each breaking point are made equal, and as the rated current increases, the number of parallel circuits increases, and as the rated voltage increases, the number of series-connected breaking points increases.

That is, in the conventional fuse element shown in FIG. 5, the flow of current in the fuse is the same both when a current near the rated current flows and when a large current flows such as when the fuse is cut off. Therefore, in order to increase the breaking performance of the fuse element, it is necessary to increase the number of breaking points in series. However, when the number of interrupting points connected in series is increased, the power dissipation when the rated current is applied increases.

[0005]

As described above, in conventional high-performance fuse elements, there is a proportional relationship between increasing the breaking performance of the fuse and increasing the power dissipation. The present invention aims to provide a fuse element with increased breaking performance while maintaining low power dissipation.

[0006]

[Means for Solving the Problems] The network fuse element according to the present invention reduces the power dissipation of the fuse by reducing the number of interrupting points connected in series when energized, and changes the current flow when energized and connects in series. This feature is characterized by increasing the number of cut-off points and increasing the cut-off performance.

The network fuse element described above is a fuse element in which P circuits having S series interrupting points having equal power dissipation are arranged in parallel, and the junctions between adjacent series interrupting points are bridged together. They are connected at the breaking point to form a network structure of breaking points, and the fusing characteristics of the adjacent P series breaking points are made to be different, so that only one of the P parallel series breaking points is connected at the last point during the breaking of this network fuse element. The present invention is characterized in that it is configured such that the current remains at the bridge breaking point, and the current flows through the bridge breaking point.

[0008] Further, in the network fuse element, the last one of the P parallel series interrupting points during the interrupting of the network fuse element is P.
It is characterized in that it is configured such that it remains alternately in sequence at either end of the series circuit.

Furthermore, the network fuse element according to the present invention increases the electrical time constant (L/R) of the loop circuit including the series breaking point and the bridge breaking point,
It is characterized in that commutation is reliably carried out even in the case of a fault current with a large current rush rate.

Furthermore, the network fuse element according to the present invention has a capacitance (C) between each series breaking point in a parallel relationship at which commutation is to be carried out, so that commutation can be carried out even in the case of a fault current with a large rush rate. It is characterized by ensuring that the flow is carried out reliably.

[0011]

[Function] This changes the number of interrupting points connected in series during continuous energization and the number of interrupting points connected in series at the end of interrupting, improving the interrupting performance and the wattage of the fuse element during continuous energization. It is possible to reduce losses at the same time. In other words, during continuous energization, the electrical characteristics of the series interrupting points are all the same, so no current flows through the bridge interrupting point, so the number of interrupting points connected in series is S, but the number of interrupting points connected in series is S. During the interruption, only one of the P parallel series interruption points remains at the end, and current flows through the bridge interruption point, so that at the final interruption, the number of interruption points connected in series remains The number is increasing.

In particular, when the last remaining one of the P parallel series cutoff points is located at either end of the P series circuits and is configured to remain alternately in sequence, the final cutoff point is The number of interrupting points connected in series at time is S+(P-
1) (S-1) pieces. Thus, 6 shown in FIG.
In the fuse element for 60V, 60A, the number S of interrupting points connected in series was 6 and the number P in parallel was 5.
If this is completely replaced with the network fuse element according to the present invention, S = 2, P = 5, the number of series cut-off points during cutoff is 6, and the number of series cut-off points during continuous energization is 6. 2, so the power loss is reduced to 1/3
can be reduced to Actually, in a low voltage fuse, the element width cannot be made very large, so there is a limit to the number of parallel circuits, and P=2 to 3 is appropriate. However, in high-voltage or special high-voltage fuses, restrictions on the width dimension are relaxed, so the larger the number of parallels P in order to shorten the length dimension, the better.
Reliable commutation of current becomes difficult, and various measures are required.

Note that if the rate of increase of the abnormal current is too rapid, the series breaking points in the parallel state may fuse very close to each other even if the fusing characteristics are changed, so the loop for these commutations may An auxiliary method is also conceivable to increase the time constant (L/R) of the circuit to make commutation more reliable. In addition, if only one side of the ceramic substrate is used as a fuse, commutation can be improved as described above by creating a metal film on the back side and providing capacitance (C) between each series interrupting point in a parallel relationship. It can be used as an auxiliary means to ensure that

[0014]

[Embodiment] Hereinafter, an embodiment will be explained with reference to the drawings. FIG. 1 is a diagram showing an example of a fuse pattern when the number S of series interrupting points is 4 and the number P of parallel circuits is 2, that is, 4S-2P. The patterns shown are constructed on ceramic with metal of the same coating thickness. Here A1
~A4 and B1 to B4 are all series breaking points, and their electrical resistances are all designed to be equal, but when breaking, the A type of A1 to A4 melts earlier than the B type of B1 to B4. Designed. For this reason, the electrical resistance is the same, and the design is such that type A is thin and short, and type B is thick and long. As a result, type B has a longer fusing time due to the difference in thermal characteristics. In this fuse pattern, one is a series circuit of four series breaking points A1-B2-A3-B4, and the other is a series circuit of four series breaking points A1-B2-A3-B4.
- Two circuits, which are series circuits of four series breaking points of A4, are placed in parallel. In this way, by having the same number of series breaking points with different thermal characteristics in the parallel circuits, we ensured that the currents in the two parallel circuits were well balanced until just before fusing, and that no cross current flowed to the bridging breaking points. .

In order to make this fuse pattern into a network structure, there are bridge breaking points C1, C2, which are connection parts.
C3 is provided, the bridge breaking point C1 connects the junction point between A1-B2 and the junction point between B1-A2, and the bridge breaking point C2 connects the junction point between B2-A3 and A2-B3. The bridge breaking point C3 connects the junction point between A3 and B4 and the junction point between B3 and A4. These bridging breaking points C1, C2, and C3 also serve as breaking points at the final moment of breaking, but they are designed so that they fuse a little later than the breaking points of the A-type and B-type.

FIG. 2 is a diagram showing the current distribution of the network fuse element shown in FIG. 1, in which (a) shows the current distribution during continuous energization, and (b) shows the current distribution at the final time of interruption. A
The electrical resistance of both the type series breaking point and the type B series breaking point are designed to be the same, so when continuous current is applied, A1-B2-A3-B4
A series circuit of four series breaking points and B1-A2-B3-A
The same current flows through the series circuit of four series breaking points of 4, as shown by two arrows in FIG. 2(a). Of course, at this time, no current flows through the bridge breaking points C1, C2, and C3.

As mentioned above, when shutting off, A1 to A4 are
The cutoff point of the mold is designed to melt earlier than the cutoff points of B type B1 to B4, so at the final cutoff, the
As shown in b), all of the series breaking points A1 to A4 of type A are fused, and only the series breaking point of type B remains, and the current flows as shown by the arrows B1-C1-B2-C2-B3. -C
3-B4 will flow in series through the seven cutoff points. In other words, when there is no bridging breaking point, final breaking is performed using four series breaking points, but in the 4S-2P network fuse element of this embodiment, 1.75
In the end, the number of series interrupting points is doubled to 7, and the interrupting performance is improved accordingly.

In order to obtain a breaking performance comparable to that of this embodiment using a conventional fuse element without a bridge breaking point, when a 7S-2P fuse element is used, the resistance of one series breaking point is set to R0. Then, the resistance of the fuse element during continuous energization is R0 x 7/2, while the resistance of the 4S-2P network fuse element of this embodiment during continuous energization is R0 x 4/2, Power loss during continuous energization is reduced by 4/7.

Similarly, in FIG. 3, the series number S is 4, and the parallel number P
It is a figure showing the fuse pattern of one example of the network fuse element of the present invention when A is set to 3;
1 to A4, A1' to A4', and B1 to B4 are all series breaking points, and their electrical resistances are all designed to be equal.
The A' type of A4' and the B type of B1 to B4 are designed to have different fusing times.

A series circuit of series breaking points A1-B2-A3-B4, a series circuit of series breaking points A1'-A2'-A3'-A4', and a series circuit of series breaking points B1-A2-B3-A4. Three circuits are connected in parallel. In order to make this fuse pattern into a network structure, bridge breaking points C1 to C3 and C1' to C3', which are connection parts, are provided, and the bridge breaking point C1 connects to the junction point between A1 and B2 and A1' to A
2', and the bridge breaking point C2 is B2-A.
Connect the junction between 3 and the junction between A2' and A3',
Bridge breaking point C3 is the junction point between A3-B4 and A3'-A4
′ is connected to the junction between Furthermore, the bridge breaking point C1'
connects the junction point between A1'-A2' and the junction point between B1-A2, and the bridge breaking point C2' connects the junction point between A2'-A3' and A2'-A3' between A2-B3. Connect the junction point,
The bridge breaking point C3' is the junction point between A3'-A4' and B3-
It connects the junction between A4 and A4.

These bridge breaking points C1 to C3 and C1'
~C3' also contributes as a cutoff point at the final time of cutoff, but the fusing time of these C type cutoff points and the previous A type, A type' and B type cutoff points is A type <A' type < B type. <It is designed like a C-type, with the A-type cutoff point being the earliest and the C-type cutoff point being the slowest.

FIG. 4 is a diagram showing the current distribution of the network fuse element of FIG. 3, in which (a) shows the current distribution during continuous energization, and (b) shows the current distribution at the final time of interruption. A
Since the electrical resistance of all the series breaking points of type A' and type B are designed to be the same, when continuous current is applied, A1
- a series circuit of four series breaking points, B2-A3-B4;
The three circuits, a series circuit of four series breaking points A1'-A2'-A3'-A4' and a series circuit of four series breaking points B1-A2-B3-A4, are shown in FIG. The same current flows as shown by the three arrows in (a). Of course, at this time, no current flows through the bridge breaking points C1 to C3 and C1' to C3'.

[0023] When the current flowing through this fuse element exceeds the rated current, first the A-type breaking points A1 to A4 are
is fused, and then A' type cutoff points A1' to A4' are fused, so that at the end of the cutoff, the cutoff points B1-C1'-C1-B2-C2-C2' are cut as shown in Fig. 4(a). -B3-C
Current will flow in series through the 10 breaking points 3'-C3-B4. That is, compared to the case without a bridge breaking point,
．． The final cutoff is performed using five times as many series cutoff points, so
The interrupting performance is improved accordingly.

When a conventional 10S-3P fuse element having a breaking performance comparable to the network fuse element of this embodiment is used, the series breaking point 1
The resistance of this fuse element is R0 x 10/3, while the resistance of the network fuse element in this example is R0 x 4/3, and the resistance of the network fuse element is R0 x 4/3, and the wattage when continuously energized is R0. The loss is 4/10 or 2.5
reduced to one-fold.

In the above explanation, each of the A type, A' type, B type, and C type breaking points seems to be composed of a single conductor having different widths and lengths, but as shown in FIG. Each conductor may be composed of a plurality of conductors, as shown in FIG. That is, FIG. 6 is another example of a 4S-2P network fuse pattern similar to that shown in FIG. The point consists of two long, thick conductors. Note that the C-type bridging break point consists of a thicker and longer single conductor, which helps increase the electrical time constant of the commutation loop circuit, and is useful for increasing the electrical time constant of the commutation loop circuit. By delaying the time it takes for the current to move to the B-type cutoff point when the cutoff point melts, it is ensured that the B-type cutoff point will blow later than the A-type cutoff point even when the current increases rapidly. It becomes like this. Further, since the length of the C-type bridge breaking point is large, the breaking performance is further improved, and good performance can be exhibited in circuits with small current and large electromagnetic energy, especially DC circuit breaking.

[0026]

As described above in detail, according to the network fuse element of the present invention, it is possible to provide a fuse with improved breaking performance while reducing power dissipation during continuous energization. For example, in order to construct a 6600V, 60A fuse using the conventional 660V, 60A 6S-5P cutoff point fuse element shown in Figure 4, it is necessary to connect 10 elements in series. Therefore, the total length of the fuse is at least 400m.
4 according to the embodiment of the invention, e.g. of FIG.
Figure 5 by network fuse element in S configuration
It is possible to obtain interrupting performance equivalent to that of fuse elements, so even if 10 pieces are arranged in series, the total length can be less than 300 mm, and the dimensions can be made smaller, allowing continuous energization. The number of interrupting points in series is 4
Since only 0 pieces are required, it is possible to reduce the power dissipation during continuous energization to 2/3 compared to 60 pieces connected in series in the conventional case.

[Brief explanation of the drawing]

[Fig. 1] Fig. 1 shows a network fuse element according to the present invention in which the number S of series breaking points is 4, and the number P in parallel is 2.
FIG. 3 is a diagram showing an example of a fuse pattern in the case of the following.

FIG. 2 is a diagram showing the current distribution of the network fuse element of FIG. 1, in which (a) shows the current distribution during continuous energization, and (b) shows the current distribution at the final time of energization.

FIG. 3 shows a network fuse element according to the present invention in which the number S of series breaking points is 4 and the number P of parallel circuits.
FIG. 3 is a diagram showing a fuse pattern of an embodiment of the network fuse element of the present invention when 3 is set.

FIG. 4 is a diagram showing the current distribution of the network fuse element of FIG. 3, in which (a) shows the current distribution during continuous energization, and (b) shows the current distribution at the final time of energization.

FIG. 5 shows an example of a fuse pattern of a conventional fuse element.

FIG. 6 shows a 4S according to the invention similar to that shown in FIG.
FIG. 6 is a diagram illustrating another example of a -2P network fuse pattern.

[Explanation of symbols]

A0 Cutoff point A, A1~A4　A type series breaking point B, B1~B4　B type series breaking point A1'~A4'A' type series breaking point

Claims (5)

[Claims] [Claim 1] During continuous energization, the number of series-connected breaking points is reduced to reduce the power dissipation of the fuse, and when the current is cut off, the current flow is changed to increase the number of series-connected breaking points to increase the breaking performance. A network fuse element characterized by: 2. A fuse element in which P circuits having S series interrupting points having equal power dissipation are connected in parallel, wherein the junctions between adjacent series interrupting points are connected to each other by a bridging interrupting point. to form a network structure of breaking points, and make the fusing characteristics of adjacent P series breaking points different, so that only one of the P parallel series breaking points remains at the end during the breaking of this network fuse element, The network fuse element according to claim 1, characterized in that a current is configured to flow through the bridge breaking point. 3. In the middle of breaking the network fuse element, the last one of the P parallel series breaking points is located at either end of the P series circuits and remains alternately in sequence. The network fuse element according to claim 2, characterized in that it comprises: 4. As an auxiliary means to the above-mentioned method of making the fusing characteristics of the series breaking points different and causing current to flow through the bridge breaking point, the electrical timing of the loop circuit including the series breaking points and the bridge breaking point is 4. The network fuse according to claim 3, wherein the constant (L/R) is increased to ensure commutation even in the case of a fault current with a large current rush rate. [Claim 5] A capacitance (C) is provided between each series breaking point in a parallel relationship at which commutation is to be carried out to ensure commutation even in the case of a fault current with a large rush rate. The network fuse according to claim 3, characterized in that: