JPH0815053A - Overheat detector for low voltage conductor - Google Patents

Abstract

PURPOSE:To simultaneously simply mount an overheat detection element at the time when ends of both conductors are connected to each other by overlapping a plurality of low voltage conductors on the mounting piece of an L-shaped thermal conduction plate, connecting one end of a shape memory alloy to a heat exchanger piece, coupling a needle connected to the other end thereof to a variable resistance slider, introducing one end of a resistance and a slider contact out of a case. CONSTITUTION:The connection part of two low voltage conductors 22 is overlapped on the mounting piece 25 of an L-shaped thermal conduction plate 23, they are tightened by screws 26, one end of a coil-like two-directional shape memory alloy 29 is connected to a heat exchanger piece 28, a movable piece 32 connected to the other end of the alloy 29 is coupled to a slider 35 of a variable resistance 34, and one end of the resistance 34 and a contact of the slider 35 are introduced out of a case 30 as a control terminal. Thereby an overheat detection element 37 is mounted simultaneously at the time when ends of both the conductors 22 are connected to each other, and mounting work is simple. In addition, design and manufacture are not needed every time sizes of the conductors 22 and correlative pitches are different.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-voltage conductor overheat detecting device for detecting abnormal overheat of a low-voltage conductor of a switchgear.

[0002]

2. Description of the Related Art A conventional low-voltage conductor overheat detecting device is as shown in FIGS. First, in FIGS. 5 and 6 showing the overall configuration, 1 is a three-phase strip-shaped low-voltage conductor arranged in parallel, 2 is two long U-shaped cleats having a U-shaped cross section, 3 Is a reinforcing ridge projecting from the outer surface of both side plates 4 of the cleat 2, and 5 are three insertion grooves formed between the edge of the side plate 4 and the ridge 3. The upper and lower cleats 2 are applied to the lower side, and the insertion grooves 5
Each conductor 1 is inserted in. 6 is a long horizontal support plate, 7 is a bent piece on the upper part of the support plate 6, and 8 is four studs, which are located in the middle part of the adjacent conductors 1 and the outer part of the outer conductor 1. , Upper and lower cleats 2 and bent pieces 7
Penetrates up and down. Reference numeral 9 denotes a nut screwed to both ends of the stud 8, and the conductors 1 are firmly sandwiched between the two cleats 2 by tightening the upper and lower nuts 9, and the support plate 6 is provided.
Supported by. 10 is three overheat detecting elements, 11 is inserted into the through hole of the side plate 4 of the lower cleat 2,
The element 10 is attached to the cleat 2, and the contact plate (described later) of the element 10 is in contact with the conductor 1. Reference numeral 12 is two output terminals of the element 10, and 13 is two control terminals provided on the lower cleat 2 and connected to the output terminal 12.

Next, the overheat detecting element 10 will be described with reference to FIGS.
Will be described. 14 is a resin case of the element 10, 15
Is a fixed contactor connected to one output terminal 12, 16 is a movable contactor connected to the other output terminal 12, 17 is a resin movable element made of an insulator having one end pivotally supported, and 18 is movable This is a pressing plate having elasticity that presses the other end of the child 17.
Reference numeral 19 is a heat-conducting backing plate that covers the mover 17, and 20 is a curved contact plate that is provided outside the backing plate 19 and is in contact with the conductor 1. Reference numeral 21 is a shape memory alloy provided on the inner surface of the backing plate 19. Then, normally, as shown in FIG. 7, the movable element 17 is in a state of being pressed by the pressing plate 18, and the both contact elements 15 and 16 are separated.

Next, when the conductor 1 becomes overheated, the heat of the conductor 1 is transferred to the shape memory alloy 21 via the contact plate 20 and the contact plate 19, the shape memory alloy 21 is deformed, and the holding plate 1 is pressed.
The movable element 17 rotates against the elasticity of 8, the movable contact element 16 contacts the fixed contact element 15 as shown in FIG. 8, contact signals are output from both output terminals 12, and the conductor 1 is not overheated. Be informed. At this time, the pressing plate 18 substantially perpendicularly contacts the surface of the mover 17, and even if the shape of the shape memory alloy 21 returns to its original shape, the mover 17 does not return to its original position, and both the contacts 15 and 16 are Keep in contact.

[0005]

In the case of the above-mentioned conventional device, since the three overheat detecting elements 10 are mounted by the screws 11 inserted through the through holes of the side plates 4 of the lower cleat 2, the elements are mounted. The work of attaching and detaching 10 is complicated, and the cleat 2 must be designed and manufactured each time due to the difference in the size of the conductor 1 and the phase pitch, and
There is a problem that the element 10 cannot be attached when the interphase dimension of the conductor 1 is short.

Further, even if the detected temperature of the element 10 is only one point and the change state of the overheat of the conductor 1 cannot be detected, and the shape of the shape memory alloy 21 is restored to the original shape, the pressing plate 18 makes a movable contact. There is a problem that the child 16 does not return to the original position and cannot be reused. In consideration of the above points, the present invention simplifies the work of attaching and detaching each overheat detecting element, and allows the conductors to be attached without designing and manufacturing each time with respect to the size of each conductor and the phase-to-phase pitch. It is an object of the present invention to provide a low-voltage conductor overheat detection device that is not affected even when the interphase dimension of is low. Furthermore, another object of the present invention is to
It has a simple structure, continuously detects changes in overheat, and enables reuse.

[0007]

In order to solve the above-mentioned problems, in the low-voltage conductor overheat detecting device of the present invention, one piece of attachment piece is provided at the connection part of two low-voltage conductors whose ends are superposed. A coiled bidirectional shape memory having a polymerized L-shaped heat conduction plate, a screw connecting the mounting piece and the low-voltage conductor, and one end connected to a heat transfer piece of the other piece of the heat conduction plate. An alloy, a mover connected to the other end of the shape memory alloy, a variable resistor having a slider connected to the mover, an insulating case covering the shape memory alloy and the variable resistor, and the case And a control terminal connected to one end of the variable resistor and a contact of the slider.

[0008]

In the low-voltage conductor overheat detecting device of the present invention configured as described above, the attachment piece of one piece of the L-shaped heat conduction plate is superposed on the connection portion of the two low-voltage conductors and connected by the screw, and One end of a coil-shaped bidirectional shape memory alloy is connected to the heat transfer piece of the other piece of the conductive plate, and the mover connected to the other end of the shape memory alloy is connected to the variable resistance slider. Since one end of the variable resistor and the contact of the slider are led out to the outer surface of the case as a control terminal, the overheat detection element can be installed at the same time when connecting the ends of both low-voltage conductors, and the installation work is extremely easy. In addition, it is not necessary to design and manufacture each low-voltage conductor with respect to the size and pitch of each low-voltage conductor, and it is possible to mount even when the inter-phase dimension of the conductor is short. In addition, the variable resistance allows continuous detection of changes in overheating, and can be reused.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIGS. In these figures, 22 is two low-voltage conductors with each end superposed, 23 is an L-shaped heat conduction plate,
24 is formed on the attachment piece 25, which is one piece of the heat conduction plate 23.
Each of the mounting notches, 26 is a connecting screw, and 27 is a nut fastened to the screw 26. The screw 26 is inserted into the overlapped end portions of both low-voltage conductors 22 and the notches 24 of the mounting piece 25, and both conductors are inserted. 22 and the heat conduction plate 23 are integrally connected. 28
Is a heat transfer piece of the other piece of the heat conduction plate 23, and 29 is a heat transfer piece 2 at one end.
Coiled bidirectional shape memory alloy connected to 8, 3
Reference numeral 0 is an insulating case fixed to the heat transfer piece 28, 31 is a guide disposed on the bottom surface of the case 30, 32 is movably provided along the guide 31, and one surface is fixed to the other end of the shape memory alloy 29. The movable element 33 is a spring provided between the other surface of the movable element 32 and the inner surface of the case 30. Reference numeral 34 denotes a variable resistor provided on the bottom surface of the case 30 in parallel with the guide 31, and reference numeral 35 denotes a slider of the variable resistor 34, which is fixed to the mover 32. Reference numeral 36 denotes a control terminal connected to one end of the variable resistor 34 and a contact of the slider 35 and led to the outer surface of the case 30. The case 30 connects the shape memory alloy 29, the mover 32, the spring 33, and the variable resistor 34. A cover and an overheat detecting element 37 are formed.

Next, the operation will be described. Conductor 22
When abnormal overheating occurs in the mounting plate 25 of the heat conduction plate 23,
Heat is transferred to the shape memory alloy 29 via the heat transfer plate 28, the shape memory alloy 29 contracts against the contraction force of the spring 33, and the slider 32 together with the mover 32 in the arrow direction of FIG. Moving toward, the resistance value of the variable resistor 34 changes, and the resistance value is continuously output from both control terminals 36 as a control signal. At this time, the spring 33 is in a stretched state.

Next, when the temperature of the conductor 22 decreases, the mover 32 moves in the direction of the arrow in FIG. 4, that is, to the right due to the restoring force of the shape memory alloy 29 and the contracting force of the spring 33, and FIG.
The state becomes as shown in and becomes the reusable state. The spring 33 does not necessarily have to be provided.

[0012]

Since the present invention is configured as described above, it has the following effects. In the low-voltage conductor overheat detecting device of the present invention, the attachment piece 25 of one piece of the L-shaped heat conduction plate 23 is superposed on the connection portion of the two low-voltage conductors 22 and connected by the screw 26, and the other piece of the heat conduction plate 23. Heat transfer piece 2
8, one end of a coil-shaped two-way shape memory alloy 29 is connected, and a mover 32 connected to the other end of the shape memory alloy 29 is connected to a slider 35 of a variable resistor 34, and a variable resistor 34. Since one end of the contact point and the contact point of the slider 35 are led out to the outer surface of the case 30 as the control terminal 36, the overheat detecting element 37 can be attached at the same time when the ends of both the low voltage conductors 22 are connected. It is extremely simple, and further, it is not necessary to design and manufacture the low-voltage conductors 22 for each size and pitch difference between the low-voltage conductors, and the conductors can be mounted even when the inter-phase dimension of the conductors is short. In addition, the variable resistor 34 allows continuous detection of changes in overheating, and can be reused.

[Brief description of drawings]

1A and 1B are a front view and a partial perspective view of an embodiment of the present invention.

FIG. 2 is a plan view of a part of FIG.

FIG. 3 is a left side view of FIG. 2;

FIG. 4 is a plan view of another state of FIG.

FIG. 5 is a front view of a conventional example.

FIG. 6 is a left side view of FIG.

7 is a partially removed front view of the overheat detecting element of FIG.

FIG. 8 is a front view of another state of FIG.

[Explanation of symbols]

 22 low-voltage conductor 23 heat conduction plate 25 mounting piece 26 screw 28 heat transfer piece 29 shape memory alloy 30 case 32 mover 34 variable resistance 35 slider 36 control terminal

Claims (1)

[Claims] 1. A L-shaped heat conduction plate having a mounting piece superposed on a connecting portion of two low-voltage conductors having respective end portions superposed, and a screw connecting the mounting piece and the low-voltage conductor. A coil-shaped bidirectional shape memory alloy having one end connected to a heat transfer piece of the other piece of the heat conduction plate, a mover connected to the other end of the shape memory alloy, and a slider. A variable resistor connected to the mover, an insulating case covering the shape memory alloy and the variable counter, led to an outer surface of the case, and connected to one end of the variable resistor and a contact of the slider. A low-voltage conductor overheat detection device having a control terminal.