JP2017183244A - Terminal overheat detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal overheat detector capable of detecting abnormal overheat of terminal by simple configuration, without modifying a circuit breaker, and capable of confirming whether or not a normal output can be obtained by test operation.MEANS FOR SOLVING THE PROBLEM: A terminal overheat detector attached to the terminal of an electrical apparatus and displaying the temperature of the terminal includes a connection connected with the terminal and to which the heat thereof is conducted, a thermal element having one end fixed to the connection and the other end disposed to displace freely in response to change of heat, a displacement transmission part to which displacement of the thermal element is transmitted and which reciprocates corresponding to response, a display mechanism which is driven by displacement transmitted from the displacement transmission part, and a signal output part which is driven when the displacement transmitted from the displacement transmission part exceeds a predetermined threshold.SELECTED DRAWING: Figure 1

Description

The present invention detects the temperature of the terminal portion of the circuit breaker and prevents the connected wires and circuit breaker from being burned out and spreading to construction materials and peripheral devices around the circuit breaker. The present invention relates to an intended terminal overheat detection device.

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

In the circuit breaker, a terminal is provided at a terminal portion of each pole in order to make an electrical connection with an electric wire or a load device. Circuit breakers built in switchboards such as residential distribution boards and control panels are drawn in at the construction site, the wires are crimped with crimp terminals, and the crimp terminals are connected to the circuit breaker by terminal screws. It is connected to the terminal by screw tightening. At this time, if the screw fastening connection between the crimp terminal and the circuit breaker terminal is insufficient, abnormal overheating may occur in the terminal during use of the circuit breaker.

In addition, even during use for many years, the terminal screw attached to the terminal may loosen due to repeated expansion and contraction due to ambient vibration and temperature change. If the screw is not tightened, abnormal overheating may occur due to loosening of the screw.

Abnormal overheating of the terminal occurs when the contact resistance between the crimp terminal and the terminal to which the electric wire is attached increases due to the looseness of the terminal screw, resulting in large Joule heat.

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, or an increase in contact resistance due to pinching of foreign matter.

If such an abnormal overheating state continues, parts constituting the circuit breaker and connected electric wires may ignite, and there is a concern about the spread of fire to construction 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. In order to prevent abnormal overheating of the terminals, measures are generally taken to confirm connection during construction and to perform periodic maintenance inspections (such as tightening terminal screws). Although these preventive measures are effective in preventing abnormal overheating, it is impossible to notice abnormal overheating until the next maintenance inspection. Can not.

Therefore, it detects the abnormal overheating of the terminal and shuts off the power supply to the load side when the abnormal overheating occurs, thereby shutting down the circuit with an overheat prevention device with a function to prevent burning accidents due to abnormal overheating. A vessel is disclosed. (Patent Document 1, Patent Document 2)

In patent document 1, the following is disclosed as what detects abnormal overheating. Bimetal plates 25 and 26 for overheat detection are fixed to the power supply side terminal and the load side terminal of the circuit breaker, and a transmission plate that is displaced following the displacement of the bimetal plate is suspended between the two bimetal plates. In addition, the operation rod that is normally locked to the transmission plate is moved by tripping the circuit breaker by releasing the locking relationship with the transmission plate due to the displacement of the transmission plate when overheated. It is to be prepared. In addition, when the engagement relationship between the transmission plate and the actuating rod is released and the actuating rod is operated, the operation rod is projected outside the circuit breaker to display the operation and press the actuating rod. Thus, an overheat prevention device that enables resetting of the circuit breaker is added to a general circuit breaker.

In patent document 2, it was made in view of the mechanical structure in the above-mentioned patent document 1, and abnormal overheating is detected electrically, and it is interrupted by an electrical signal output when the abnormal overheating is detected. What drives a tripping device that opens the contact of the container is disclosed.

Specifically, the mechanical operation disclosed in Patent Document 1 is made in view of the fact that it cannot be applied unless the internal mechanism of the circuit breaker is changed. In addition, the circuit breaker in the power supply system can be centrally managed, and can be used for overheating protection of other devices such as an electromagnetic switch provided in the same circuit.

As a configuration for detecting abnormal overheating, a temperature-sensitive element whose electrical output changes corresponding to the temperature of the wire connection terminal, and detecting the abnormal overheating by comparing the electrical output of the temperature-sensitive element with a normal level And a determination circuit.

Examples of the temperature sensing element include a thermistor, a thermocouple using a thermoelectromotive force, an infrared sensor for detecting radiant heat, and the temperature sensing element is arranged near the terminal of the mold case as an arrangement form of the temperature sensing element. The temperature sensor unit is configured to be embedded and disposed on a resin-molded insulating support independent of the mold case, and the temperature sensor unit is integrated using the mounting groove of the interelectrode 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 mounted between the back surface of the mold case and the board surface, a terminal used to insulate the circuit breaker terminal part The temperature sensor is embedded in an insulator, such as a ceramic with high thermal conductivity, attached to the cover, inserted into a hole provided in the insulation support of the temperature sensor unit, and long by a spring. Resiliently held so as to be movable in a direction, such as in the form of contacting the distal end of the insulator is disclosed in breaker terminals.

Japanese Utility Model Publication No. 56-25156 JP 62-8419 A

As disclosed in Patent Document 1 and Patent Document 2, it is possible to add a function of detecting abnormal overheating of a terminal to a normal circuit breaker. However, in Patent Document 1, it is necessary to provide a space for arranging a mechanical mechanism for detecting abnormal overheating on the entire back surface side of the circuit breaker when adding a function for detecting abnormal overheating. Since the circuit breaker is greatly modified, such as the external shape of the circuit breaker is greatly changed, there is a problem of increase in man-hours and cost.

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

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

The terminal temperature display device according to the present invention is configured to solve the above-described problems,

A terminal temperature display device that is attached to a terminal of an electrical device and displays the temperature of the terminal,

A connecting portion connected to the terminal and conducting heat of the terminal;

A thermal element having one end fixed to the connection portion and the other end arranged to be displaceable in response to the change in heat;

A displacement transmitting portion that transmits the displacement of the thermal element and reciprocates in response to the response;

A display mechanism that is driven by transmission of displacement of the displacement transmission unit;

And a signal output unit that is driven when the displacement of the displacement transmission unit is transmitted and exceeds a predetermined threshold value. The terminal overheat detection device is configured.

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 a terminal with a simple configuration without requiring modification of the circuit breaker.

In addition, while the connection portion where the thermal element is disposed is disposed corresponding to the number of terminals of the circuit breaker,

The displacement transmission unit is provided in common for each thermal element,

The maximum displacement in each thermal element is transmitted to the displacement transmission part,

The signal output unit may be driven.

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

In addition, while a part of the connection part is exposed to the outside, the thermodynamic element, the displacement transmission part, the display mechanism, and a substantially rectangular parallelepiped housing that houses the signal output part,

A test operation unit for driving the signal output unit by displacing the displacement transmission unit by operating from the outside of the housing may be provided.

According to such a configuration, since the driving of the signal output unit can be confirmed by the test operation unit, it is possible to test whether the signal output unit can normally output a signal.

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

The schematic of the state which attached the terminal overheat detection apparatus which shows embodiment of this invention to the circuit breaker is shown. The schematic of the attachment method of said terminal overheat detection apparatus is shown. The terminal overheat detection device is shown. The internal assembly figure of said terminal overheat detection apparatus is shown. Sectional drawing AA (assembly structure of a switch means) shown in FIG. 4 is shown. The external appearance of the test operation means of said terminal overheat detection apparatus is shown. Sectional drawing BB (assembling structure of a test operation means) shown in FIG. 6 is shown. The structure which detects the connection failure of the terminal in a prior art example is shown.

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

In FIG. 1, the schematic block diagram of the state which attached the terminal overheat detection apparatus 2 which concerns on this embodiment to the circuit breaker 1 is shown. In FIG. 2, the schematic of the attachment method of a terminal overheat detection apparatus is shown. FIG. 3 shows a terminal overheat detection device. FIG. 4 shows an internal assembly diagram of the terminal overheat detection device. FIG. 5 shows an assembly structure of the switch means of the terminal overheat detection device. FIG. 6 shows test operation means of the terminal overheat detection device. FIG. 7 shows an assembly structure of the test operation 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 FIG. 1 and FIG. 2, the circuit breaker 1 is comprised by the circuit breaker housing | casing whose outer shell consists of a mold case. The circuit breaker housing includes a base 101 for mounting the internal components of the circuit breaker and a cover 102 that covers the internal components and covers the base. In the circuit breaker 1, there are a fixed contact (not shown) integrated with the terminal 12 and a movable contact (not shown) in order to turn on and off the electric circuit on the power source side and the electric circuit on the load side. Is disposed. Also, an opening / closing mechanism (not shown) that opens and closes the fixed contact and the movable contact, and a tripping operation of the opening / closing mechanism by acting on the opening / closing mechanism by detecting an abnormal current flowing in the electric circuit. And a tripping device (not shown) for opening the stationary contact and the movable contact.

The circuit breaker 1 is provided with a plurality of terminals 12 connected to external conductors corresponding to the power sources of the respective poles, 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 fixed to the terminal 12 with a terminal screw 11.

Next, the terminal overheat detection device 2 attached to the circuit breaker 1 will be described with reference to FIGS. 1 and 2. The heat conduction terminal 21, which is a connection portion that is connected to the terminal 12 and conducts heat of the terminal 12 of the terminal overheat detection device 2, has a through hole that penetrates the terminal screw 11 of the circuit breaker 1. The heat conduction terminal 21 is fastened 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 temperature display device 2 is located between the mounting surface of the circuit breaker 1, that is, 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 overheating 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 temperature display device 2 is connected to the terminal 12 of each pole of the circuit breaker 1, and a heat conduction terminal 21 that is a connection part through which the heat of the terminal 12 is conducted. The first thermal transmission element 22 fixed to the thermal conduction terminal 21 and a displacement transmission unit that is disposed in the vicinity of the thermal dynamic element 22 and that transmits the displacement of the thermal dynamic element 22 and reciprocates in response to the response. Operating body 23, a second operating body 24 that is disposed in the vicinity of the first operating body 23, and that is also a displacement transmitting portion that reciprocates in response to the reciprocating displacement of the first operating body 23, and displacement transmission A microswitch 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 element 22, first operating body 23, second operating body 24, microswitch And a housing 26 for storing 25.

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

The first actuating body 23 is urged to abut against the position restricting portion 261 of the housing 26 by an elastic member (not shown) that urges the first actuating body 23, so that the first actuating body 23 is spaced from the thermal element 22 by a certain gap. It arrange | positions in the state which provided.

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

When the heat generation at the terminal 12 is cured, the displacement of the thermal element 22 is reduced. Since the displacement of the thermal element 22 is reduced, the first operating body 23 and the second operating body 24 are elastic members (not shown) that urge the first operating body 23 or the second operating body 24. The terminal 12 is rotated to a position before the terminal 12 generates heat by the elastic member 241 that urges. When the abnormal overheating of the terminal 12 is subsided, that is, when the magnitude of the 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 microswitch 25 is operated so as not to output a signal notifying that the terminal 12 is abnormally overheated.

The heat generated at the terminal 12 is conducted through the heat conducting 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 displacement amount of the thermal element 22. Therefore, since 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, when the terminal 12 is abnormally overheated, That is, when the displacement of the thermal element 22 exceeds a certain amount and when the terminal 12 is not abnormally overheated, that is, when the displacement of the thermal element 22 is less than a certain amount, It can be configured such that the state of the contact operating portion of the switch 25 is switched.

With such a configuration, 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 terminal overheat detection device 2 does not need to be modified. 2 can be attached. Further, by configuring the contact operating part of the micro switch 25 to operate when the displacement of the thermal element 22 fixed to the heat conducting terminal 21 exceeds a certain amount, the terminal can be configured with a simple configuration. 12 abnormal overheat states can be output.

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 is not limited to this, for example, a thermal element The micro switch 25 may be operated by directly contacting the contact operating portion of the micro switch 25 with 22.

Further, in the present embodiment, the operation of the contact operating portion of the micro switch 25 is configured to be in a state where it does not come into contact with the contact operating portion when the thermal element 22 is displaced. It goes without saying that a configuration may be adopted in which the moving element 22 is brought into a contact state from a non-contact state when the moving element 22 is displaced.

Next, the terminal overheat detection device 2 that can monitor a plurality of terminals 12 at once and can detect abnormal overheat by the terminal 12 that generates the most heat will be described with reference to FIGS. 4 and 5.

The first actuating 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, only the thermal element 22 that is displaced at the highest temperature among the thermal elements 22 that are fixed to the terminal 12 of the pole across which the first actuator 23 extends is the first actuator. 23 interlocks and rotates in the direction A shown in FIG. 5 against an elastic member (not shown) that biases the first operating body 23, and the second operating body 24 is rotated by the first operating body 23. Is rotated in the direction B shown in FIG. 5 against the elastic member 241 so that the contact operating portion of the micro switch 25 can be operated. Therefore, the heat generation state of the plurality of terminals 12 over which the first operating body 23 extends can be collectively monitored, and abnormal overheating can be detected based on the terminal 12 that generates the most heat. Thereby, it is possible to detect abnormal overheating of each terminal 12 with a smaller number of parts than when the terminal overheat detection device 2 is arranged at each terminal 12.

4 and 5, the microswitch 25 is configured to be operated via the first operating body 23 and the second operating body 24. However, the present invention is not limited to this, and for example, the first operating body. The micro switch 25 may be operated by directly contacting the operation unit 251 of the micro switch 25.

Next, the terminal overheat detection device 2 that can test whether the microswitch 25 can normally output a signal by intentionally operating the microswitch 25 as the switch means by the test operation means is shown in FIGS. The description will be made with reference to FIG.

As shown in FIG. 6, a test operation means 27 is inserted in a surface near the microswitch 25 in the casing 26 in which the microswitch 25 is arranged.

As shown in FIG. 7, one end side of the test operation means 27 is exposed to the outside of the casing 26, and the other end side of the test operation means 27 is inside the casing 26 so that the operation means of the microswitch 25 can be operated. The test elastic member 271 is inserted together. In the case of this embodiment, the other end side of the test operation means 27 is disposed 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 casing 26 is operated, the other end side of the test operation means 27 is the operation part of the microswitch 25 and the displacement of the thermal element 22 is constant. Operate as if the amount was exceeded. For example, in the case of FIGS. 5, 6, and 7, when one end side of the test operation means 27 is pushed, the test operation means 27 moves toward the inside of the housing 26 against the test elastic member 271. The other end side of the test operation means 27 is configured to rotate the second operating body 24 in the direction B 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 is possible to confirm that the microswitch 25 operates normally by the presence or absence of signal output of the microswitch 25 when the test operation means 27 is operated. The detection device 2 can be provided.

5, 6, and 7, the second operating body 24 is rotated by pushing the test operation means 27. However, the present invention is not limited to this, and the test operation means 27 is moved in some way. It goes without saying that the operation unit of the microswitch 25 may be operated by the operation. For example, the test operation means is not limited to the push button type, but may be a slide button type, and the test operation means 27 is not limited to the configuration in which the second operation body 24 is rotated, but the first operation body 23 is rotated. It is good also as a structure to make it operate, or a structure which operates the operation part of the microswitch 25 directly.

In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 11 Terminal screw 12 Terminal 2 Terminal overheat detection apparatus 21 Thermal conduction terminal 22 Thermal element 23 First action body 24 Second action body 241 Elastic member 25 Switch means (microswitch)
26 Case 261 Position restricting portion 27 Test operation means 271 Test elastic member 3 Electric wire 31 Crimp terminal

Claims (3)

A terminal overheat detection device that is attached to a terminal of a circuit breaker and detects the temperature of the terminal,
A connecting portion connected to the terminal and conducting heat of the terminal;
A thermal element having one end fixed to the connection portion and the other end arranged to be displaceable in response to the change in heat;
A displacement transmitting portion that transmits the displacement of the thermal element and reciprocates in response to the response;
A display mechanism that is driven by transmission of displacement of the displacement transmission unit;
And a signal output unit that is driven when a displacement of the displacement transmitting unit is transmitted and exceeds a predetermined threshold value.
While the connection portion where the thermal element is disposed is disposed corresponding to the number of the terminals of the circuit breaker,
By providing the displacement transmission part in common to each of the thermal elements,
The maximum displacement in each of the thermal elements is transmitted to the displacement transmission unit,
The terminal overheat detection device according to claim 1, wherein the signal output unit is driven.
While a part of the connection part is exposed to the outside, the thermodynamic element, the displacement transmission part, the display mechanism, and a substantially rectangular parallelepiped housing that houses the signal output part,
3. The terminal overheat detection device according to claim 1, further comprising a test operation unit that drives the signal output unit by displacing the displacement transmission unit by operating from the outside of the housing. .

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