JP6792343B2 - Terminal overheat detector - Google Patents

Description

The present invention detects the temperature of the terminal portion of the circuit breaker to prevent the connected electric wire and the circuit breaker from being burnt and the fire from spreading to the construction materials and peripheral devices around the circuit breaker. Regarding the target terminal overheat detection device.

The circuit breaker detects an accident current such as an overcurrent, a short-circuit current, or an electric leakage current in an electric circuit, and when a predetermined operating condition is met, the circuit breaker operates so as to cut off the supply of power to the load side.

The circuit breaker is provided with terminals at the terminals of each pole in order to make an electrical connection with an electric wire or a load device. For circuit breakers built into distribution boards such as residential distribution boards and control boards, electric wires are pulled in at the construction site, the electric wires are caulked at the crimp terminals, and the crimp terminals are connected by crimp terminals to the circuit breakers. It is connected to the terminal by screw tightening. At this time, if the screw tightening connection between the crimp terminal and the terminal of the circuit breaker is insufficient, abnormal overheating may occur in the terminal while using the circuit breaker.

In addition, even during long-term use, repeated expansion and contraction due to ambient vibration and temperature changes may cause loosening of the terminal screws attached to the terminals, and regular maintenance and inspection (terminals) If the screws are not retightened), abnormal overheating may occur due to loosening of the screws.

Abnormal terminal overheating occurs when the contact resistance between the crimp terminal to which the electric wire is attached increases due to the loosening of the terminal screw and a large Joule heat is generated.

In addition, abnormal overheating also occurs due to an increase in contact resistance due to oxidation of the contact surface between the crimp terminal of the electric wire and the terminal of the circuit breaker, and an increase in contact resistance due to pinching of foreign matter.

If such an abnormally overheated state continues, the parts constituting the circuit breaker and the connected electric wires may ignite, and there is a concern that the fire may spread to the building materials and peripheral devices around the circuit breaker.

However, a normal circuit breaker does not have a function of detecting abnormal overheating of these terminals. Generally, to prevent abnormal overheating of terminals, measures are taken to check connections during construction and perform regular maintenance and inspection (tightening of terminal screws, etc.). Although these preventive measures are effective in preventing abnormal overheating, it is not possible to notice abnormal overheating until the next maintenance and inspection, so it is not possible to completely prevent burning accidents and fire spread accidents due to aging. Can not.

Therefore, by detecting abnormal overheating of the terminals and cutting off the power supply to the load side when abnormal overheating occurs, a circuit breaker with an overheat prevention device equipped with a function to prevent burning accidents due to abnormal overheating The vessel is disclosed. (Patent Document 1, Patent Document 2)

Patent Document 1 discloses the following as a means for detecting abnormal overheating. Bimetal plates 25 and 26 for overheat detection are fixed to the power supply side terminal and load side terminal of the circuit breaker, respectively, and a transmission plate that displaces according to the displacement of the bimetal plate is suspended between these two bimetal plates. And, although it is always locked to the transmission plate, when it is overheated, the displacement of the transmission plate releases the locking relationship with the transmission plate, so that the actuating rod moves to trip the circuit breaker. To prepare. Further, when the locking relationship between the transmission plate and the operating rod is released and the operating rod operates, the operating rod protrudes to the outside of the circuit breaker to display the operation and press the operating rod. An overheat prevention device that enables the circuit breaker to be reset by the above is added to a general circuit breaker.

In Patent Document 2, in consideration of the mechanical structure in Patent Document 1 described above, abnormal overheating is electrically detected, and the abnormal overheating is blocked by an electric signal output due to the detection. Disclosed is what drives a trip device that opens the contacts of the vessel.

Specifically, the mechanical operation disclosed in Patent Document 1 is often not applicable unless the internal mechanism of the circuit breaker is changed. In particular, the prevention of overheating of the circuit breaker alone is achieved. In addition to this, the problem was that the circuit breakers in the power supply system could be centrally managed and could be used for overheat protection of other devices such as electromagnetic switches installed in the same circuit.

As a configuration for detecting abnormal overheating, a temperature-sensitive element whose electrical output changes according to the temperature of the electric wire connection terminal and an abnormal overheating are detected by comparing the electrical output of the temperature-sensitive element with a normal level. It is equipped with a judgment circuit.

Examples of the temperature-sensitive element include a thermistor, a thermocouple using thermocouple, an infrared sensor for detecting radiated heat, and the like. The temperature-sensitive element is arranged near the terminal of the mold case. A form of embedding and arranging, a temperature sensor unit is configured by holding it on a resin-molded insulating support independently of the mold case and integrated, and the temperature sensor unit is integrated by using a groove for mounting an interpole barrier. A form attached to the mold case, a form in which the temperature sensor unit is formed in a plate shape so that it can be attached by sandwiching it between the back surface and the board surface of the mold case, and a terminal used for insulating the circuit breaker terminal portion A temperature-sensitive element is embedded in an insulator such as ceramic with high thermal conductivity, which is attached to the cover, and inserted into a hole provided in the insulating support of the temperature sensor unit so that it can be moved in the length direction by a spring. A form in which the tip of the insulator is brought into contact with the circuit breaker terminal while being elastically held is disclosed.

Jikkensho 56-25156 Japanese Unexamined Patent Publication No. 62-8419

As disclosed in Patent Document 1 and Patent Document 2, it is possible to add a function of detecting abnormal overheating of terminals to a normal circuit breaker. However, in Patent Document 1, in order to add the function of detecting abnormal overheating, it is necessary to separately provide a space for arranging a mechanical mechanism for detecting abnormal overheating on the entire back surface side of the circuit breaker. Since the circuit breaker is significantly modified, such as the outer shape of the circuit breaker is significantly changed, there are problems such as an increase in man-hours and an increase in cost.

Further, in Patent Document 2, when arranging an electric device, it is necessary to separately provide a unit provided with a temperature sensor such as a temperature sensing element and a determination circuit, and attach the unit to a circuit breaker. Since there are many parts to be added and it is necessary to introduce it as a temperature measurement system, it is complicated to add functions. Further, since an electric element such as a temperature sensitive element is used, there is a problem that it is difficult to tell at a glance whether or not a failure has occurred in long-term use.

Therefore, the present invention has been made in view of the above problems, and whether or not an abnormal overheating of terminals can be detected with a simple configuration without the need for modification of a circuit breaker and a normal output can be obtained by a test operation. It is an object of the present invention to provide a terminal overheat detection device capable of confirming whether or not.

The terminal overheat detection device according to the present invention is configured to solve the above-mentioned problems, is a terminal overheat detection device that is attached to a terminal of an electric device to detect the temperature of the terminal, and is connected to the terminal. A connection portion through which the heat of the terminal is conducted, a thermal element in which one end is fixed to the connection portion and the other end is displaced in response to a change in heat, and the thermal element. It is provided with a displacement transmission unit that transmits the displacement of the above and reciprocates in response to a response, and a signal output unit that is driven when the displacement of the displacement transmission unit is transmitted and exceeds a predetermined threshold. The terminal overheat detection device is configured as a feature.

According to such a configuration, the displacement of the displacement transmission unit is transmitted by conducting the heat of the terminal overheat detection device to the terminal of the circuit breaker, and the signal output unit is driven when the displacement exceeds a predetermined threshold value. Since the configuration is adopted, it is possible to provide a terminal overheat detection device that can detect abnormal overheating of terminals with a simple configuration without the need to modify the circuit breaker.

Further, the connection portion in which the thermal element is arranged is arranged according to the number of terminals of the circuit breaker, while the displacement transmission portion is provided in common to each thermal element. The configuration may be characterized in that the maximum displacement of each thermal element is transmitted to the displacement transmission unit to drive the signal output unit.

According to this configuration, the signal output unit can be driven by capturing the heat generated by the terminal that generates the most heat from the plurality of terminals of the circuit breaker, so that it is not necessary to arrange a switch means for each terminal. Therefore, a plurality of terminals can be collectively monitored with a small number of parts.

Furthermore, said part of the connection portion is exposed to the outside, while having a thermally activated element, and a displacement transmitter, a housing of substantially rectangular parallelepiped shape for accommodating the signal output unit,

The displacement transmission unit may be displaced by operating from the outside of the housing to include a test operation unit for driving the signal output unit.

According to such a configuration, since the drive of the signal output unit can be confirmed by the test operation unit, it is possible to test whether or not the signal output unit can output a signal normally.

As described above, according to the present invention, it is possible to detect abnormal overheating of terminals with a simple configuration without the need to modify the circuit breaker, and to confirm whether or not a normal output can be obtained by a test operation. A capable terminal overheat detection device can be provided.

A schematic view of a state in which a terminal overheat detection device showing an embodiment of the present invention is attached to a circuit breaker is shown. The schematic diagram of the mounting method of the said terminal superheat detection device is shown. The above terminal overheat detection device is shown. The internal assembly drawing of the said terminal superheat detection device is shown. FIG. 4 shows a cross-sectional view AA (assembly structure of the switch means) shown in FIG. The appearance of the test operation means of the terminal superheat detection device is shown. FIG. 6 shows a cross-sectional view BB (assembled structure of test operating means) shown in FIG. The structure for detecting the connection failure of the terminal in the conventional example is shown.

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration diagram of a state in which the terminal superheat detection device 2 according to the present embodiment is attached to the circuit breaker 1. FIG. 2 shows a schematic view of how to attach the terminal overheat detection device. FIG. 3 shows a terminal overheat detection device. FIG. 4 shows an internal assembly drawing of the terminal overheat detection device. FIG. 5 shows the assembly structure of the switch means of the terminal overheat detection device. FIG. 6 shows a test operation means of the terminal overheat detection device. FIG. 7 shows the assembly structure of the test operating means. FIG. 8 shows a structure for detecting a terminal connection failure in the conventional example.

First, the basic structure of the circuit breaker 1 shown in FIGS. 1 and 2 will be described. In FIGS. 1 and 2, the circuit breaker 1 is composed of a circuit breaker housing whose outer shell is a mold case. The circuit breaker housing includes a base 101 on which the internal parts of the circuit breaker are mounted, and a cover 102 that covers the base and covers the internal parts. Inside the circuit breaker 1, a fixed contact (not shown) integrated with the terminal 12 and a movable contact (not shown) are provided inside the circuit breaker 1 in order to turn on / off the electric circuit on the power supply side and the electric circuit on the load side. Is arranged. Further, an opening / closing mechanism (not shown) that drives the fixed contact and the movable contact to open / close, and an abnormal current flowing through the electric circuit are detected to act on the opening / closing mechanism to pull the opening / closing mechanism. A tripping device unit (not shown) for opening and driving the fixed contact and the movable contact is provided.

The circuit breaker 1 is provided with a plurality of terminals 12 connected to an external conductor corresponding to the power supply of each pole, and each of them is exposed to the outside.

An electric wire 3 is connected to the terminal 12 from the outside. A crimp terminal 31 is attached to the tip of the electric wire 3 by caulking, and the crimp terminal 31 is screwed and fixed to the terminal 12 by a terminal screw 11.

Next, the terminal superheat detection device 2 attached to the circuit breaker 1 will be described with reference to FIGS. 1 and 2. The heat conductive terminal 21 which is a connection portion of the terminal overheat detection device 2 which is connected to the terminal 12 and conducts the heat of the terminal 12 has a through hole through which the terminal screw 11 of the circuit breaker 1 is passed. The heat conductive terminal 21 is tightened and fixed by the terminal screw 11 so as to be sandwiched between the crimp terminal 31 and the terminal 12 of the electric wire 3. The terminal overheat detection device 2 is located on the mounting surface of the circuit breaker 1, that is, between the bottom surface of the circuit breaker 1 and the electric wire 3 connected to the terminal 12 at the time of mounting.

Next, the configuration of the terminal overheat detection device 2 having a function of detecting abnormal overheating of the terminal 12 will be described with reference to FIGS. 3, 4 and 5.

As shown in FIGS. 3, 4 and 5, the terminal overheat detection device 2 is connected to the heat conduction terminal 21 which is a connection portion connected to the terminal 12 of each pole of the circuit breaker 1 and conducts the heat of the terminal 12. The first displacement transmission unit, which is arranged in the vicinity of the thermal element 22 fixed to the thermal conductive terminal 21 and the thermal element 22, is a displacement transmission unit that transmits the displacement of the thermal element 22 and reciprocates in response to the response. And the second operating body 24, which is also a displacement transmitting unit and is arranged in the vicinity of the first operating body 23 and reciprocates in response to the reciprocating displacement of the first operating body 23, and displacement transmission. The micro switch 25, which is a signal output unit that is driven when the displacement of the unit is transmitted and exceeds a predetermined threshold, and these thermal elements 22, the first operating body 23, the second operating body 24, and the micro switch. It is configured to include a housing 26 for accommodating 25.

The thermal element 22 fixed to the heat conductive terminal 21 is configured by using a bimetal that receives heat conduction from the heat conductive terminal 21 connected to the terminal 12 and is quantitatively displaced. In FIGS. 4 and 5, the thermal element 22 is fixed to the heat conductive terminal 21 by screw tightening, but it is not limited to screw tightening and may be fixed by welding or rivets.

The first operating body 23 is urged by an elastic member (not shown) that urges the first operating body 23 so as to abut against the position regulating portion 261 of the housing 26, and has a constant gap with the thermal element 22. Is arranged in a state of being provided.

As shown in FIG. 5, the second operating body 24 is urged by the elastic member 241 so as to abut on the microswitch 25. The second operating body 24 is the first operating body that rotates in the A direction shown in FIG. 5 in response to the displacement of the thermal element 22 when the thermal element 22 is displaced by heat conduction from the heat conductive terminal 21. In conjunction with 23, it rotates in the B direction shown in FIG. 5 against the elastic member 241. When the terminal 12 is abnormally overheated, that is, when the magnitude of displacement of the thermal element 22 exceeds a certain amount, the contact operation portion of the microswitch 25 is operated by the second operating body 24, so that the microswitch 25 is operated. Is operated to output a signal notifying the abnormal overheating of the terminal 12.

When the heat generated by the terminal 12 subsides, the displacement of the thermal element 22 becomes smaller. By reducing the displacement of the thermal element 22, the first operating body 23 and the second operating body 24 are an elastic member (not shown) for urging the first operating body 23 or a second operating body 24. The elastic member 241 that urges the terminal 12 rotates to the position before the terminal 12 generates heat. When the abnormal overheating of the terminal 12 has subsided, that is, when the magnitude of displacement of the thermal element 22 becomes a certain amount or less, the contact operating portion of the microswitch 25 is operated by the second operating body 24. The micro switch 25 is operated so as not to output a signal notifying the abnormal overheating of the terminal 12.

The heat generated by the terminal 12 is thermally conducted through the heat conductive terminal 21. Since the thermal element 22 is quantitatively displaced according to the amount of heat, the first operating body 23 and the second operating body 24 rotate according to the amount of displacement of the thermal element 22. Therefore, the amount of heat generated by the terminal 12, the amount of displacement of the thermal element 22, and the amount of rotation of the first operating body 23 and the second operating body 24 are correlated. Therefore, when the terminal 12 is abnormally overheated, That is, when the magnitude of the displacement of the thermal element 22 exceeds a certain amount and when the terminal 12 is not abnormally overheated, that is, when the magnitude of the displacement of the thermal element 22 is a certain amount or less, the micro It can be configured so that the state of the contact operation unit of the switch 25 is switched.

With such a configuration, the heat conduction terminal 21 of the terminal overheat detection device 2 is attached to the terminal 12 of the existing circuit breaker with the terminal screw 11, so that the circuit breaker 1 does not need to be modified and the terminal overheat detection device does not need to be modified. 2 can be attached. Further, by configuring the contact operation unit of the microswitch 25 to be operated when the displacement of the thermal element 22 fixed to the heat conductive terminal 21 exceeds a certain amount, the terminal can be easily configured. Twelve abnormally overheated states can be output.

Note that, in FIGS. 4, 5 and 6, the microswitch 25 is configured to be operated via the first operating body 23 and the second operating body 24, but the present invention is not limited to this, and for example, a thermal element. The microswitch 25 may be operated by the 22 directly contacting the contact operation portion of the microswitch 25.

Further, in the present embodiment, the operation of the contact operation portion of the micro switch 25 is configured to change from a state of being in contact with the contact operation portion to a state of not being in contact with the contact operation portion when the thermal element 22 is displaced. Needless to say, the structure may be such that when the moving element 22 is displaced, it changes from a non-contact state to a contact state.

Next, a terminal overheat detection device 2 capable of collectively monitoring a plurality of terminals 12 and detecting abnormal overheating by the terminal 12 that generates the most heat will be described with reference to FIGS. 4 and 5.
The first operating body 23 shown in FIG. 4 is rotatably fixed to the housing 26 so as to extend over the terminals 12 of each pole.

With such a configuration, among the thermal elements 22 fixed to the terminal 12 of the pole over which the first operating body 23 extends, only the thermal element 22 displaced at the highest temperature is the first operating body. 23 interlocks and rotates in the direction A shown in FIG. 5 against an elastic member (not shown) that urges the first operating body 23, and the first operating body 23 causes the second operating body 24. Can operate the contact operating portion of the microswitch 25 by rotating in the B direction shown in FIG. 5 against the elastic member 241. Therefore, the heat generation state of the plurality of terminals 12 across the first operating body 23 can be collectively monitored, and abnormal overheating can be detected based on the terminal 12 that generates the most heat. As a result, abnormal overheating of each terminal 12 can be detected with a smaller number of parts than when the terminal overheating detection device 2 is arranged at each terminal 12.

Note that, in FIGS. 4 and 5, the microswitch 25 is configured to be operated via the first operating body 23 and the second operating body 24, but the present invention is not limited to this, and for example, the first operating body is not limited to this. The microswitch 25 may be operated by the 23 directly in contact with the operating portion 251 of the microswitch 25.

Next, the terminal superheat detection device 2 capable of testing that the microswitch 25 can output a signal normally by intentionally operating the microswitch 25 which is a switch means by the test operation means is shown in FIGS. 5 and 6. And FIG. 7 will be described.

As shown in FIG. 6, in the housing 26 in which the microswitch 25 is arranged, the test operating means 27 is inserted on the surface in the vicinity of the microswitch 25.

As shown in FIG. 7, one end side of the test operating means 27 is exposed to the outside of the housing 26, and the other end side of the test operating means 27 is inside the housing 26 so that the operating means of the microswitch 25 can be operated. It is inserted together with the test elastic member 271 toward. In the case of this embodiment, the other end side of the test operating means 27 is arranged so as to rotate the second operating body 24.

When one end side of the test operation means 27 exposed to the outside of the housing 26 is operated, the other end side of the test operation means 27 makes the operation part of the micro switch 25 constant in the magnitude of displacement of the thermal element 22. Operate in the same way as when the amount is exceeded. For example, in the case of FIGS. 5, 6 and 7, when one end side of the test operating means 27 is pushed, the test operating means 27 moves toward the inside of the housing 26 against the elastic member 271 for testing. The other end side of the test operating means 27 is configured to rotate the second operating body 24 in the B direction shown in FIG.

With such a configuration, the operation unit of the micro switch 25 can be intentionally operated by operating the test operation means 27. As a result, it can be confirmed that the micro switch 25 operates normally by the presence or absence of the signal output of the micro switch 25 when the test operation means 27 is operated. Therefore, the terminal overheating that enables the test operation confirmation of the micro switch 25 to be easily confirmed. The detection device 2 can be provided.

Note that, in FIGS. 5, 6 and 7, the second operating body 24 is rotated by pressing the test operating means 27, but the present invention is not limited to this, and the test operating means 27 is used in some way. Needless to say, the operation unit of the micro switch 25 may be operated by the operation. For example, the test operating means is not limited to the push button type but may be a slide button type, and the test operating means 27 is not limited to the configuration in which the second operating body 24 is rotated, and the first operating body 23 is rotated. It may be configured to be operated or the operation unit of the micro switch 25 may be directly operated.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention.

1 Circuit breaker 11 Terminal screw 12 Terminal 2 Terminal overheat detection device 21 Heat conduction terminal 22 Thermal element 23 First actuator 24 Second actuator 241 Elastic member 25 Switch means (micro switch)
26 Housing 261 Position control unit 27 Test operating means 271 Test elastic member 3 Electric wire 31 Crimping terminal

Claims (2)

A terminal overheat detection device that is attached to the terminal of a circuit breaker to detect the temperature of the terminal.
A connection portion that is connected to the terminal and conducts heat of the terminal,
A thermal element in which one end is fixed to the connection portion and the other end is displaceably arranged in response to the change in heat.
A displacement transmission unit that transmits the displacement of the thermal element and reciprocates in response to the response.
A signal output unit that is driven when the displacement of the displacement transmission unit is transmitted and exceeds a predetermined threshold value is provided .
The connection portion on which the thermal element is arranged is arranged according to the number of terminals of the circuit breaker, while the connection portion is arranged.
By providing the displacement transmission unit in common with each of the thermal elements,
The maximum displacement of each of the thermal elements is transmitted to the displacement transmission unit,
A terminal overheat detection device characterized by driving the signal output unit .
Said part of the connection portion is exposed to the outside, one comprising said thermally activated element, and the displacement transmitting unit, a casing of substantially rectangular parallelepiped shape for accommodating the prior SL signal output unit,
Wherein by displacing the displacement-transmitting section by operating from the outside of the housing, according to claim 1 Symbol mounting terminal overheat detecting apparatus characterized by comprising a test operation unit for driving the signal output unit.

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