JP5402378B2 - Circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker having an overcurrent protection function and a ground fault protection function applied to a low voltage distribution system.

  As is well known, the circuit breaker applied to the low-voltage distribution system is a circuit breaker (MCCB: Molded Case Circuit Breaker) with an overcurrent protection function, and an earth leakage breaker with an overcurrent protection function and a ground fault protection function. There is a container (ELCB: Earth Leakage Circuit Breaker).

  The above circuit breaker has a structure in which the main circuit contact, the switching mechanism, the operation handle, and the functional parts of the overcurrent tripping device are mounted on the main body case (molded resin case) of the circuit breaker. On the other hand, the earth leakage circuit breaker has a zero-phase current transformer that detects the unbalanced current of the main circuit using the main circuit as a primary conductor, A leakage detection circuit (electronic circuit including IC) that detects the occurrence of a ground fault from the secondary output level of the current transformer, and a trip coil unit that trips the circuit breaker switching mechanism in response to the output signal of the leakage detection circuit It becomes the composition equipped with. Note that, as a control power source for the leakage detection circuit, normally, the interphase voltage of the main circuit is rectified and supplied to the leakage detection circuit.

  In addition, general-purpose products for circuit breakers and earth leakage circuit breakers currently produced in Japan are designed to have the same circuit breaker as the main body case of the same external size in order to improve the user-friendliness. The mainstream is a configuration in which common protective functional parts are installed in the case.

  On the other hand, for circuit breakers for circuit breakers and earth leakage circuit breakers, the interphase dielectric strength of the main circuit is specified by the standard, and the test is performed from the outside with the contact of the main circuit of the breaker open. High voltage) is applied to measure the insulation strength of the product. In this case, in the earth leakage circuit breaker, since the earth leakage detection circuit constituted by an electronic circuit is connected to the control power supply circuit branched and connected to the main circuit, in order to protect the earth leakage detection circuit from the test voltage, Therefore, it is necessary to separate the leakage detection circuit from the main circuit during the withstand voltage test. Therefore, a power withstand voltage test switch (mega test switch) linked to the open / close mechanism of the earth leakage circuit breaker is additionally provided, and the power supply circuit is connected to the earth leakage detection circuit by turning the switch OFF during the withstand voltage test. In conjunction with this switch operation, the circuit breaker switching mechanism is mechanically forcibly tripped to open the main circuit contact, and the circuit breaker is held in this open state. An earth leakage breaker is also known (see, for example, Patent Document 1).

JP 2007-317361 A

  By the way, for circuit breakers used in low-voltage distribution facilities, users generally select either a circuit breaker for wiring or a circuit breaker according to the situation of the distribution facilities in the facility, type of load used, etc. . However, depending on the user, at the start of the operation of the newly established on-site distribution equipment, initially the leakage breaker was adopted to check the presence of leakage current (ground fault current) generated in the distribution circuit and the magnitude of the leakage current. After that, many users are using the circuit breaker by replacing it with a circuit breaker because they don't want the circuit breaker to trip due to low leakage current and stop the operation of the load (for example, motor). In addition, when changing the load used in the power distribution facility, depending on the type of load, the circuit breaker used so far may be replaced with a leakage breaker.

  However, in the past, there are two types of circuit breakers used in low-voltage distribution systems: circuit breakers for wiring and earth leakage circuit breakers. The user can selectively use overcurrent protection and ground fault protection functions with one unit. At present, there is no circuit breaker product that can be used in the future. In addition, in the above-mentioned Patent Document 1, a mega test switch is inserted in the power supply circuit that supplies power to the leakage detection circuit. However, since this mega test switch is linked to the switching mechanism of the circuit breaker, It cannot be used as a circuit breaker with the protection function disabled.

  Therefore, the present invention is a novel circuit in which the protection function of the circuit breaker can be selectively switched by a simple operation so that the user can use it as a circuit breaker or a leakage breaker if necessary. The purpose is to provide a circuit breaker.

In order to achieve the above object, according to the present invention, a main circuit contact, a switching mechanism, an overcurrent trip device, and a leakage trip device including a zero-phase current transformer and a leakage detection circuit are mounted on the main body case. In the circuit breaker with overcurrent protection function and ground fault protection function to be configured,
Equipped with a mode changeover switch unit that turns on and off the contact point inserted in the power supply circuit that feeds power from the main circuit to the leakage detection circuit. The mode changeover switch unit is built in the main body case of the circuit breaker and detects the leakage of the main circuit. A switch body connected to a power supply circuit between the circuit, an actuator linked to an operation end of the switch body, and a push button type switch operation unit for turning on and off the contact via the actuator, the actuator Is provided with one lever arm linked to the operation end of the switch body and the other lever arm opposed to the tip of the push button of the switch operation portion, and the tip of the other lever arm is connected to the opening / closing mechanism. so as not to cooperate component of trip cross bar, oN pushbutton of the switch operation unit, the ground fault by OFF operation Protection function "valid", and selects set to "invalid" (claim 1).
In the circuit breaker , the switch body includes an insulating switch case in which the poles are partitioned, a fixed electrode disposed on the bottom side of the switch case as a pair of left and right contacts, and the fixed electrode. It is an assembly of a bridge-shaped movable contactor arranged opposite to each other and an operation rod that holds the movable contactors of each pole at the same time and is pulled out above the switch case. so as to place the free space between the side walls of the mounting the zero-phase current transformer and the main body case (claim 2).
Further, in the above circuit breaker , the actuator is a swinging lever combined with a biasing spring, one lever arm extending on both sides of the pivot shaft portion is connected to the operation rod of the switch body, and the other The lever arm is arranged so as to oppose the tip of the push button (claim 3 ).
Further, in the above circuit breaker , the switch operating unit includes a push / twist lock type push button and a cylindrical support guide that is mounted on the cover of the circuit breaker body case surrounding the push button and its return spring. A vertical slit that is an assembly and that guides the push button in the ON / OFF direction by inserting a protrusion formed on the tip side of the push button on the peripheral surface of the cylindrical guide, and a lower end of the slit from circumferentially extending so as to form an engaging step portion for engaging holding the pushbutton in the locked position (claim 4).

  According to the above configuration, the ground fault protection function of the circuit breaker can be selected and set to the “valid” or “invalid” mode simply by switching the pushbutton of the mode changeover switch unit equipped on the circuit breaker. it can. As a result, the ground fault protection function of the circuit breaker is temporarily switched to “valid” in order to check whether leakage current is flowing in the distribution circuit of the on-site power distribution facility on the user side, and then the ground fault protection function Switch to “invalid” and use as a circuit breaker. Alternatively, a circuit breaker that was used as a circuit breaker with the ground fault protection function set to “invalid” can be used as a ground fault circuit breaker by returning the ground fault protection function to “enabled”. Become.

It is a circuit diagram of the circuit breaker by the Example of this invention. It is a disassembled perspective view showing the assembly structure of the circuit breaker corresponding to FIG. It is a block diagram of the mode changeover switch unit in FIG. 1, (a) is a disassembled perspective view of the whole unit, (b) is the perspective view seen from the lower surface side of the cylindrical guide. It is an internal structure figure of a switch main part in Drawing 3, and (a) and (b) are figures showing a state of switch ON and OFF, respectively. FIG. 4 is an operation explanatory diagram of the mode changeover switch shown in FIG. 3, and (a) and (b) are diagrams showing the push-up and push-in states, respectively.

Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS.
First, FIG. 1 is a circuit diagram of a circuit breaker according to the present invention, in which 1 is a main circuit corresponding to each phase of R, S, and T, 2 is a main circuit contact, and 3 is a switching mechanism of the main circuit contact 2 Reference numerals 4 and 4 are operation handles, and 5 is an overcurrent tripping device for detecting the overload current and short circuit current of the main circuit 1 and tripping the switching mechanism 3. An earth leakage trip device that trips the switching mechanism 3 by detecting a ground fault current in the distribution path uses the main circuit 1 of each phase R, S, T as a primary conductor to detect the unbalanced current. A current detecting circuit (electronic circuit including IC) 7 for detecting the occurrence of a ground fault from the secondary output level of the current transformer 6 and the zero-phase current transformer 6; and an opening / closing mechanism section that receives an output signal from the current detecting circuit 7 3 comprises a trip coil unit 8 for tripping.

  Here, the leakage detection circuit 7 feeds the inter-phase voltage of the main circuit via the power supply line 9 and the rectifier circuit 10 branchedly connected to the main circuit 1 of each phase as its control power supply. A mode changeover switch unit 11 according to the invention is connected. The detailed structure of the mode switch unit 11 will be described later. In the illustrated example, the R, S, and T phase voltages of the main circuit are DC-converted and supplied, but the R-T phase voltage may be supplied to the leakage detection circuit 7 in some cases.

  Next, FIG. 2 shows an assembly structure of the entire circuit breaker on which the mode changeover switch unit 11 is mounted. In FIG. 2, 12 is a main body case of a circuit breaker having a divided structure of a case 12a, a cover 12b and a top cover 12c. Here, the main body case 12 includes an opening / closing mechanism unit 3, an operation handle 4, an overcurrent trip device 5, a zero-phase current transformer 6, a leakage detection circuit 7, a trip coil unit 8, and R, S, and T phases. Each functional component of the trip crossbar 15 that receives the mechanical output signals of the main circuit conductor 13, the arc extinguishing chamber 14, and the trip coil unit 8 corresponding to the phases and trips the opening / closing mechanism unit 3 is laid out as shown in the figure. It is installed.

  Further, the space in the case surrounded by the annular core of the zero-phase current transformer 6, the side wall of the case 12a, and the U-shaped main circuit conductor (R phase) 13 inserted into the annular core of the zero-phase current transformer. The above-mentioned assembly of the mode changeover switch unit 11 is accommodated and arranged. Further, the cover 12b is assembled with a push button 16 for turning on / off the switch body of the unit facing the mode changeover switch unit 11, and the top cover 12c has an operation window hole corresponding to the push button 16. 12c-1 is open.

Next, the detailed structure of the mode changeover switch unit 11 and the push button 16 will be described with reference to FIG. This mode changeover switch unit 11 is composed of an assembly of a switch body 17, an actuator 18 linked to the operation end of the switch body 17, and a unit case 19. Here, the switch body 17 is as shown in FIG. A box-shaped switch case (molded resin case) 17a that is partitioned by a partition, a fixed electrode 17b that is assembled on the lower side of the switch case 17a with a pair of left and right contacts as a set, and a bridge that faces the fixed electrode 17b And a movable contact holder 17d that holds the movable contacts 17c of the respective poles together and pulls the operation end upward from the switch case 17a. A hook is attached to the tip of the contact holder 17d. A shaped knob 17d-1 is formed.

  With the above configuration, when the knob portion 17d-1 is pushed in the direction of arrow A in FIG. 4A, the movable contact 17c contacts the fixed electrode 17b and the switch is turned on. When the contact holder 17c is lifted in the direction of arrow B in FIG. 4B, the movable contact 17c is separated from the fixed electrode 17b, and the switch is turned off.

  And this switch main body 17 is fitted and attached to the switch support step part 19a formed in the middle step position of the unit case 19 as shown in FIG. Reference numeral 20 denotes a lead wire wired to the fixed electrode 17b of the switch body 17 and drawn from the switch case 17a.

  Further, an engagement convex portion 19c is formed on the outer surface of the unit case 19, and the engagement convex portion 19c is mounted in the state where the mode changeover switch unit 11 is mounted on the body case 12 of the circuit breaker as shown in FIG. The portion 19c is fitted into an engagement groove 12a-1 formed by cutting out the upper edge of the side wall of the case 12a so as to be positioned and held at a fixed position.

  The actuator 18 has a shaft 18a as a swinging fulcrum and a swinging lever with lever arms 18b and 18c extending on the left and right sides thereof as a base, and the shaft 18a has a biasing spring 18d (torsion coil). The shaft portion 18a is pivotally supported by a bearing portion 19b provided on the top of the unit case 19 so as to be swingable. An engaging arm portion 18b is formed at the tip of a lever arm 18b extending rightward from the shaft portion 18a. The engaging arm portion 18b is hooked on a knob portion 17d-1 drawn upward from the switch body 17. The lever arm 18c extending to the left from the shaft portion 18a is opposed to the tip of the push button 16 disposed on the case cover 12 as described later. The urging spring 18d assembled to the actuator 18 urges the lever arm 18b clockwise in the free state of the actuator to push the switch body 17 into the ON position and drive it.

  On the other hand, the push button 16 is a push / twist lock type button, and is fitted and held in a cylindrical guide 22 formed integrally with the cover 12b of the main body case 12 in combination with a return spring 21 (compression coil spring). At the position, the tip of the push button 16 faces the lever arm 18 c of the actuator 18.

  Further, a groove for inserting a screwdriver (tool) is cut into the head of the push button 16, and an engagement protrusion 16 a formed at the tip of the shaft portion extending downward from the head is formed at the tip of the cylindrical guide 22. Engagement and retention are maintained. Further, a guide protrusion 16b is formed on the peripheral surface of the head of the push button 16, and a longitudinal guide slit 22a and an end of the slit 22a are formed on the peripheral surface of the cylindrical guide 22 corresponding to the protrusion 16b. An engagement step portion 22b extending in the circumferential direction is formed (see FIG. 3B). With this structure, the push button 16 is guided in the pushing direction, and the push button 16 is locked and held at the pushing position by a push / twist operation.

  Next, operations and functions of the mode changeover switch unit 11 and the push button 16 will be described with reference to FIGS. 5 (a) and 5 (b). That is, in the initial state of the circuit breaker shipped from the manufacturer, the push button 16 is pushed up above the cylindrical guide 22 by receiving the spring force of the return spring 21 as shown in FIG. In this state, the actuator 18 of the mode changeover switch unit 11 receives the spring force of the urging spring 18d (see FIG. 3) and swings clockwise to push down the movable contact holder 17d (see FIG. 4) of the switch body 17. The contact is kept on. Thereby, the main circuit 1 and the leakage detection circuit 7 shown in FIG. 1 are connected via the power supply line 9, and the interphase voltage of the main circuit 1 is supplied to the leakage detection circuit 7 via the rectifier circuit 10. . Therefore, in this state, the circuit breaker functions as a leakage breaker.

  On the other hand, when the push button 16 is fully pushed in the direction of arrow A in FIG. 5B by using a tool such as a screwdriver from outside, the tip of the push button 16 pushes the actuator 18 of the mode changeover switch unit 11. The lever 16c is pushed to drive it counterclockwise, and the push button 16 itself engages with the engaging step 22b formed on the cylindrical guide 22 by the projection 16b on the head, and the spring force of the return spring 21 is increased. Received and held in the pushing position. The actuator 18 is also held by the push button 19 and held in this position.

  As a result, as shown in FIG. 4B, the contact holder 17d is pulled up in the direction of the arrow B in the switch body 17, and the contact is turned off, thereby disconnecting the circuit of the power line 9 in FIG. As a result, the leakage detection circuit 7 is disconnected from the main circuit 1 and the function as the leakage breaker is released, and the circuit breaker functions as a wiring breaker.

  Further, in order to supply the main circuit voltage to the leakage detection circuit 7 from this state so that the circuit breaker functions as the leakage breaker, the push button 16 is twisted in the opposite direction from the outside of the breaker case. To do. As a result, the protrusion 16 b of the push button 16 is disengaged from the engagement step portion 22 b of the cylindrical guide 22, and the push button 16 is pushed upward by receiving the spring force of the return spring 21. Therefore, the lever arm of the actuator 18 that has been pressed by the push button 16 is swung clockwise by the spring force of the biasing spring 18d, and the movable contact holder 17d of the switch body 17 is pushed in so that the switch is turned on. return. As a result, the leakage detection circuit 7 returns to the state where power is supplied from the main circuit 1, and the circuit breaker functions as a leakage breaker.

  As can be seen from the above description, the mode changeover switch unit connected to the power supply circuit between the main circuit 1 and the leakage detection circuit 7 of FIG. The ground contact protection function of the circuit breaker can be set to “valid” or “invalid” by turning on and off the 11 switch contacts. As a result, the user can use the circuit breaker installed in the power distribution facility as an earth leakage breaker or a circuit breaker as necessary.

  In addition, when conducting a withstand voltage test (mega test) of a circuit breaker in a state where it is used as a leakage breaker, the leakage detection circuit of the electronic circuit is turned off by turning off the mode switch. It can be disconnected from the main circuit of the circuit breaker and protected safely from the test voltage.

DESCRIPTION OF SYMBOLS 1 Main circuit 2 Main circuit contact 3 Opening and closing mechanism part of main circuit contact 5 Overcurrent trip device 6 Zero phase current transformer 7 Leakage detection circuit 8 Trip coil unit 9 Power supply line 11 of earth leakage detection circuit Mode changeover switch unit 12 Circuit breaker Main body case 16 push button 17 switch main body 17b fixed electrode 17c movable contact 17d movable contact holder 18 actuator 19 unit case 21 return spring 22 cylindrical guide

Claims (4)

Equipped with a main circuit contact, switching mechanism, overcurrent trip device, and an earth leakage trip device that includes a zero-phase current transformer and leakage detection circuit in the main body case. Circuit breakers
Equipped with a mode changeover switch unit that turns on and off the contact point inserted in the power supply circuit that feeds power from the main circuit to the leakage detection circuit. The mode changeover switch unit is built in the main body case of the circuit breaker and detects the leakage of the main circuit. A switch body connected to a power supply circuit between the circuit, an actuator linked to an operation end of the switch body, and a push button type switch operation unit for turning on and off the contact via the actuator, the actuator Is provided with one lever arm linked to the operation end of the switch body and the other lever arm opposed to the tip of the push button of the switch operation portion, and the tip of the other lever arm is connected to the opening / closing mechanism. so as not to linked to the part of the trip cross bar, oN pushbutton of the switch operation unit, the ground fault by OFF operation Protection function "valid", the circuit breaker and selects set to "invalid". 2. The circuit breaker according to claim 1 , wherein the switch body is a fixed electrode disposed on the bottom side of the switch case as a combination of a switch case made of an insulator in which each pole is partitioned and a pair of left and right contacts. And a movable movable contact member arranged opposite to the fixed electrode, and an operation rod that holds the movable contact members of the respective poles together and is drawn out above the switch case, and cuts off the switch body. A circuit breaker characterized in that the circuit breaker is arranged in a vacant space between the zero-phase current transformer mounted on the main body case of the vacuum vessel and the side wall of the main body case. 2. The circuit breaker according to claim 1 , wherein the actuator is a swinging lever combined with a biasing spring, and one lever arm extending on both sides of the pivot shaft is connected to the operation rod of the switch body. The circuit breaker is characterized in that the other lever arm is arranged to oppose the tip of the push button. 2. The circuit breaker according to claim 1 , wherein the switch operating portion includes a push / twist lock type push button, and a cylindrical support guide that surrounds the push button and its return spring and is attached to the cover of the breaker body case. A vertical slit that guides the push button in the ON / OFF direction by inserting a protrusion formed on the distal end side of the push button on the peripheral surface of the cylindrical guide, and below the slit A circuit breaker characterized in that an engagement step portion is formed extending in a circumferential direction from a side end and engaging and holding a push button at a lock position.