JP6650207B2 - Terminal connection failure detection device - Google Patents

Description

  The present invention detects abnormal overheating of a terminal to which a circuit breaker and an electric wire are connected, and connects the terminal to prevent burnout of the circuit breaker and spread of fire to building materials and peripheral devices around the circuit breaker. The present invention relates to a terminal connection failure detection device that detects a failure.

  As is well known, a circuit breaker is provided on an electric circuit, and detects an overcurrent, a short-circuit current, or an accidental current such as a leakage current in the electric circuit, and electrically connects the electric circuit when a predetermined operating condition is met. It operates so as to shut off the power supply to the load side.

  The circuit breaker is provided with a connection terminal that enables electrical connection with an external circuit to be repeated. In a circuit breaker installed on a distribution board such as a distribution board or a control board for a house and connected to a power supply line of an external circuit drawn into the panel, the power supply line and a circuit are installed at a construction site where the distribution board is installed. The terminal on the power supply side of the circuit breaker is connected. At this time, if the connection between the power supply line and the connection terminal on the power supply side of the circuit breaker is in an insufficient state, abnormal overheating may occur in the terminal portion.

  In addition, during use for many years, there is a possibility that the terminals may be loosened due to repeated occurrence of ambient vibration or temperature change. There is a possibility that abnormal overheating may occur at the terminal part, for example, when the opportunity for regular maintenance and inspection is not properly obtained, or when the tightening of the terminal is not sufficiently confirmed.

  The causes of abnormal overheating of the terminals to which the wires are connected in the circuit breaker include insufficient tightening of the terminal screws and loosening of the terminal screws due to long-term use. Increase. A large Joule heat is generated due to an increase in the electric resistance of the connection portion, and heat generation at the terminal portion is assumed.

  In addition, heat may be generated due to an increase in contact resistance due to oxidation of the contact surface between the power supply line and the connection terminal of the circuit breaker, creep of the electric wire, or the presence of foreign matter.

  In addition, the cause of the abnormal heating of the part other than the connection part between the power supply line and the connection terminal part is that the internal resistance is caused by wear and dropout of the contacts in the circuit breaker due to aging, oxidation or the presence of foreign matter, etc. Heat generation due to the increase can be assumed.

  If such abnormal overheating continues, the parts that make up the circuit breaker will be burned out, and the circuit breaker itself will be burned out. There is a concern that fire may spread to peripheral equipment.

  However, ordinary circuit breakers are not provided with a function to detect these abnormal overheats.To prevent abnormal overheat, measures have been taken to check connections during construction and perform regular maintenance and inspections. I was Although these precautionary measures are effective in preventing abnormal overheating, in terms of suppressing abnormal overheating once it has occurred, there is a risk that abnormal overheating will be difficult to notice until the next maintenance inspection. Concerns about the risk of burnout and fire spread due to excessive use could not be completely eliminated.

Therefore, a circuit with an overheat prevention device having a function of detecting these abnormal overheatings and, when the abnormal overheating occurs, shutting off the power supply to the load side and preventing a burnout accident caused by the abnormal overheating. A circuit breaker is disclosed. (Patent Document 1, Patent Document 2)
Patent Document 1 discloses the following as a device for detecting abnormal overheating. Bimetal plates 25 and 26 for detecting overheating are fixed to the power supply side terminal and the load side terminal of the circuit breaker, respectively, and a transmission plate displaced following the displacement of the bimetal plate is suspended between the two bimetal plates. And, at all times, the operating rod is locked to the transmission plate, but when overheated, the movement of the transmission plate is released by releasing the locking relationship with the transmission plate due to the displacement of the transmission plate, thereby tripping the circuit breaker. It is provided. Further, when the locking relationship between the transmission plate and the operating rod is released and the operating rod operates, the operation indicator is displayed by projecting the operating rod outside the circuit breaker, and the operating rod is pressed. And an overheat prevention device which enables resetting of the circuit breaker by adding to a general circuit breaker.

  Patent Document 2 is made in view of the mechanical structure of Patent Document 1 described above, and electrically detects abnormal overheating and shuts off by an electric signal output when the abnormal overheating is detected. A device for driving a trip device that opens a contact of a vessel is disclosed.

  Specifically, the mechanical operation disclosed in Patent Literature 1 has been made in view of the fact that it often cannot be applied unless the internal mechanism of the circuit breaker is changed. In addition to the above, it is an object of the present invention to centrally control a circuit breaker in a power supply system or to use the circuit breaker for overheating protection of another device 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 in accordance with the temperature of the wire connection terminal, and an abnormal output is detected by comparing the electrical output of the temperature-sensitive element with a normal level. A determination circuit.

  Examples of the temperature sensing element include a thermistor, a thermocouple using thermoelectromotive force, an infrared sensor for detecting radiant heat, and the like. Formed to be embedded and arranged independently of the mold case to form an integrated temperature sensor unit held by a resin-molded insulating support, using the mounting groove of the inter-electrode barrier for the temperature sensor unit Form attached to the mold case, Forming the temperature sensor unit into a plate shape so that it can be mounted between the back surface of the mold case and the board surface, Terminal used for insulating the temperature sensing element terminal part of the breaker The temperature sensing element is embedded in an insulator such as ceramic with high thermal conductivity attached to the cover, inserted into the hole provided in the insulating support of the temperature sensor unit, and extended 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-A-62-8419

  As disclosed in Patent Documents 1 and 2, it is possible to add a function of detecting abnormal overheating to a normal circuit breaker. However, in Patent Document 1, in order to add a 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 side of the circuit breaker. In addition, significant remodeling of the circuit breaker accompanies, for example, the outer shape of the circuit breaker changes greatly.

  Further, in Patent Document 2, when arranging the electric device, it is necessary to separately provide a unit having a temperature sensor such as a temperature sensing element and a determination circuit, and attach the unit to a circuit breaker. Because of the large number of components and the necessity of introducing it as a temperature measurement system, it is complicated to add functions. In addition, since the temperature sensing element is attached after being electrically insulated from the main circuit, there is a problem that the temperature is indirectly sensed and an accurate temperature rise is difficult to catch.

  In any case, it functions as a single function for detecting abnormal overheating. In view of the recent trend of circuit breakers, it is necessary to maintain or improve the electrical safety performance while saving the space of the circuit breakers, that is, to maintain or improve the current breaking performance while reducing the external size of the circuit breakers. Although improvement is required, there is a problem that it is not practical to further configure a circuit breaker by adding a function of detecting abnormal overheating related to electrical safety.

  Therefore, the present invention has been made in view of the above problems, and can be retrofitted to a normal circuit breaker, and the mounting position is affected by the position of the circuit breaker body, the wires connected to the circuit breaker, and the like. It is an object of the present invention to provide a connection failure detecting device which is not affected by the problem and can be mounted without removing the circuit breaker from the mounting plate upon mounting.

A connection failure detection device according to the present invention is configured to solve the above-described problem, and includes a connection portion that is connected to a power supply terminal of a circuit breaker so as to be capable of conducting heat and electricity, and a power supply terminal. A bimetal that is displaced in accordance with the heat generation state of the power terminal due to the heat conduction of the power supply terminal, a display unit that displays the state of heat generation by receiving and driving the bimetal in contact with the bimetal, And a housing for accommodating the display unit, a bimetal, and a display unit. The circuit breaker can be freely attached to and detached from a power supply terminal from outside while the circuit breaker is mounted at a predetermined mounting position. As a terminal connection failure detection device.

  According to this configuration, the connection portion is configured to be connected to the power supply terminal of the circuit breaker from outside the circuit breaker. Since the power supply terminal can be freely attached to and detached from the power supply terminal, the connection failure detection device can be mounted without removing the circuit breaker from the mounting plate.

  Further, the mounting position of the connection failure detecting device may be located between the mounting surface of the circuit breaker and the electric wire connected to the power terminal.

  According to such a configuration, an empty space in a normal circuit breaker can be used, and the position of an electric wire or the like connected to the circuit breaker is less likely to be affected.

  As described above, according to the present invention, it can be retrofitted to a normal circuit breaker, and its mounting position is not affected by the position of the circuit breaker body or the wires connected to the circuit breaker, and It is possible to provide a connection failure detection device that can be mounted without removing the circuit breaker from the mounting plate upon mounting.

1 is a schematic configuration diagram illustrating a state in which a connection failure detection device according to a first embodiment of the present invention is attached to a circuit breaker. The principal part schematic diagram in the state where the above-mentioned poor connection detecting device was attached to the circuit breaker is shown. FIG. 2 shows a schematic configuration diagram of the above connection failure detection device. 1 shows a structure for detecting a terminal connection failure in a conventional example.

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

(First embodiment)
FIG. 1 is a schematic configuration diagram illustrating a state in which a poor connection detection device 2 according to the present embodiment is attached to a circuit breaker 1. FIG. 2 is a schematic view of a main part in a state where the connection failure detecting device is mounted on a circuit breaker. FIG. 3 shows a schematic configuration diagram of the connection failure detection device.

  First, the basic structure of the circuit breaker 1 will be described. The circuit breaker 1 is configured such that its outer shell is covered by a body made of a molded case. The housing comprises a base to which components of the circuit breaker are mounted and fixed, and a cover which covers the main components by being put on the base. A plurality of power supply terminals 111 connected to an external conductor are provided corresponding to the power supply of each pole, and each is exposed to the outside.

  An insulating wall 11 is provided between the power terminals 111 to insulate the respective power terminals.

  A fixed contact 110 and a movable contact 112 which turn on and off an electric circuit on the power supply side and an electric circuit on the load side are arranged inside the housing.

  Further, an opening / closing mechanism for opening and closing the fixed contact 110 and the movable contact 112 and an abnormal current flowing through an electric circuit are detected to act on the opening / closing mechanism to cause the opening / closing mechanism to perform a tripping operation. And a trip device for driving the fixed contact 110 and the movable contact 120 to open.

  At one end of the fixed contact 110, a power supply terminal 111 connected to a conductor on the power supply side is provided, and at the other end, a fixed contact is provided.

  A movable contact 112 provided with a movable contact facing the fixed contact 110 is disposed opposite the fixed contact 110, and is held by an opening / closing mechanism to be driven to open and close with respect to the fixed contact 110.

  The electric wire 3 is connected to the power terminal 111 from outside. A crimp terminal 31 is attached to the distal end of the electric wire 3 by caulking, and the crimp terminal 31 is fixed to the power supply terminal 111 with a terminal screw 1103.

(Connection failure detection device 2)
Next, the configuration of the connection failure detecting device 2 that realizes the function of detecting the connection failure of the electric wire 3 at the power supply terminal 111 will be described.

  The connection failure detecting device 2 receives the heat conduction from the power supply terminal 111 and is displaced in accordance with the heat generation state of the power supply terminal 111 by receiving the heat conduction from the power supply terminal 111. A thermodynamic element 22; a display unit 23 for displaying a state of heat generation in response to the displacement of the thermodynamic element 22; and a housing 24 accommodating the connection unit 21, the thermodynamic element 22, and the display unit 23. Be composed.

  The connection portion 21 has a through hole through which the terminal screw 1103 of the circuit breaker 1 penetrates, so that the connection portion 21 is sandwiched between the crimp terminal 31 of the electric wire 3 and the power supply terminal 111 when attached to the power supply terminal 111. Then, it is tightened and fixed by the terminal screw 1103. By being fixed in this way, heat is conducted directly to the connection. In addition, since it is fixed while maintaining electrical conductivity, an increase in contact resistance can be prevented.

  The thermal element 22 is configured using a bimetal that is displaced by receiving heat conduction from the connection part 21 connected to the power supply terminal 111. Specifically, the thermal element 22 is fixed to the connection part 21 by welding.

  The display unit 23 is disposed in the vicinity of the thermodynamic element 22, and is driven to contact by receiving the displacement of the thermodynamic element 22. Specifically, the thermodynamic element 22 is rotatably held with a rotation axis in a direction orthogonal to the direction of displacement. The display unit 23 is provided with a contact part with the thermal element 22 and a visual recognition part visually recognized from the outside.

  The connection part 21, the thermodynamic element 22, and the display part 23 are housed in a housing 24 and integrally formed. The housing 24 has a width corresponding to one pole of each pole of the circuit breaker 1, and can be attached to a predetermined pole. Specifically, when all three poles are mounted, each housing 24 is formed so as not to come into contact with each other. The height direction is formed to have a size that fits between the mounting surface of the circuit breaker 1 and the electric wire 3 connected to the power terminal 111.

  The housing 24 is provided with a confirmation window at a location corresponding to the viewing portion so that the viewing portion of the display unit 23 can be viewed from outside the housing 24.

  Although the temperature of the power supply terminal 111 fluctuates depending on the magnitude of the current used, the configuration is such that the state when the temperature of the power supply terminal 111 is at the maximum value can be maintained. The force required to rotate the display unit 23 is provided by a predetermined amount, so that the rotationally advanced displacement can be held. Specifically, the predetermined magnitude is set to a force smaller than the displacement force (driving force of the bimetal) of the thermodynamic element 22, and even when the displacement of the thermodynamic element 22 returns, the display section 23 The rotation can keep the maximum value.

(Mounting position of connection failure detection device 2)
The connection failure detecting device 2 is located between the mounting surface of the circuit breaker 1 and the electric wire 3 connected to the power supply terminal 111 at the time of mounting.

  More specifically, the connection failure detecting device 2 is attached and fastened by the terminal screws 1103 such that the connection portion 21 is sandwiched between the crimp terminal 31 of the electric wire 3 and the power supply terminal 111.

  By being fixed in this manner, the housing 24 is located between the mounting surface of the circuit breaker 1 and the electric wire 3 and is settled in the dead space, and is connected to the circuit breaker main body and the electric wire connected to the circuit breaker. It is hard to be affected by the position such as.

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

  For example, the housing 24 of the connection failure detecting device 2 is formed to have a size for each pole and each pole. However, in the case of a circuit breaker used as a main switch, it has a size of three poles. The connection part 21, the thermal element 22 and the display part 23 may be formed and housed in a housing together with three poles.

  With this configuration, the trouble of mounting the connection failure detecting device 2 for each pole can be omitted.

  Further, the drive of the display unit 23 is a rotary type provided with a rotary shaft, but may be configured as a linear movement type in which the display unit is pushed in a certain direction in accordance with the displacement of the thermodynamic element 22.

DESCRIPTION OF SYMBOLS 1 Circuit breaker 11 Insulating wall 110 Fixed contact 1103 Terminal screw 111 Power terminal 112 Movable contact 2 Connection failure detecting device 21 Connection part 22 Thermal element 23 Display part 24 Housing 3 Electric wire 31 Crimp terminal

Claims (2)

A connection portion that is connected to a power terminal of the circuit breaker so as to be able to conduct heat and electricity,
A bimetal that receives heat conduction from the power terminal and is displaced in accordance with the heat generation state of the power terminal;
A display unit that displays a state of heat generation by being driven in contact with the bimetal in response to the displacement of the bimetal ,
A housing for accommodating these connection parts, bimetals, and display parts,
A terminal connection failure detecting device characterized in that the circuit breaker can be freely attached to and detached from a power supply terminal from the outside while the circuit breaker is mounted at a predetermined mounting position. The mounting position of the connection failure detection device is as follows:
The connection failure detecting device according to claim 1, wherein the device is located between a mounting surface of the circuit breaker and an electric wire connected to a power terminal.

Images