JP2006120563A - Ground fault interrupter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a switch for breakdown strength test mounted on a ground fault interrupter for its operability, visual confirmation of ON/OFF action position, and interlocking function with an opening/closing mechanism, and to add a switch without changing the layout of main components of the interrupter. <P>SOLUTION: A manual switch 11 for testing the breakdown strength for closing/opening a feeding circuit between a ground fault detecting circuit 7 and a main circuit, comprises an assembly unit, consisting of a switch body 16, a switch operation part 17 of push/twist lock type for ON/OFF operation of the contact of the switch body, and an actuator 18 interlocked with the switch operation part arranged in the space beside a zero-phase current transformer 6 in the body case 12 of the interrupter. The operation end of the actuator is made to face a trip cross bar 15, at the arranged position to mechanically interlock with it. The trip cross bar 15 is driven and arrested at a latch-releasing position, interlocked with the OFF operation of the switch for testing breakdown strength, to trip the interrupter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an earth leakage breaker having an overcurrent protection function and a ground fault protection function applied to a low voltage distribution system, and more particularly, to disconnect an earth leakage detection circuit from a main circuit when performing an insulation / withstand voltage test of the earth leakage breaker. The present invention relates to an assembly structure of a withstand voltage test switch as a protection means.

There are wiring breakers and earth leakage circuit breakers as protection devices for the low-voltage distribution system, and the earth leakage circuit breakers currently deployed in the domestic market generally have an overcurrent protection function and a ground fault protection function. Is. Also, in recent earth leakage breakers, in order to improve the convenience on the customer side, the circuit breakers for wiring and earth leakage breakers of the same frame are made into a main body case of the same external size, and the main parts are shared as much as possible. An earth leakage circuit breaker having a single structure configured as described above has become mainstream (see, for example, Patent Document 1).
The earth leakage protection means in this earth leakage breaker includes a zero-phase current transformer that detects unbalanced current using the main circuit as the primary conductor, and an earth leakage detection that detects the occurrence of a ground fault from the secondary output level of the zero-phase current transformer. A circuit (electronic circuit including IC) is mounted, and the circuit breaker switching mechanism is tripped in response to the output signal of the leakage detection circuit. Further, a power supply line is wired between the main circuit and the leakage detection circuit as a control power supply for the leakage detection circuit, and the interphase voltage of the main circuit is rectified and supplied to the leakage detection circuit.

On the other hand, it is stipulated in the standard that the products of earth leakage breakers have a predetermined interphase dielectric strength with respect to the main circuit of each phase mounted in the main body case. Mega test) is performed to check whether or not a predetermined insulation strength is secured. This insulation / withstand voltage test is performed by applying a test voltage between the phases of the main circuit terminals with the main circuit contact of the earth leakage breaker turned OFF, and the test voltage is the rated voltage of the earth leakage breaker. For example, the test voltage in the earth leakage breaker having a rated voltage of 400 to 600V is 2500V.
By the way, when the insulation / withstand voltage test is performed and the test is performed with the leakage detection circuit connected to the main circuit, the leakage detection circuit, which is an electronic circuit, is destroyed at a high test voltage. Therefore, in order to make it easy to conduct insulation and withstand voltage tests at the site where the earth leakage breaker is used, the earth leakage breaker body case is equipped with a withstand voltage test switch (mega test switch) to turn on / off the breaker. The power supply circuit of the leakage detection circuit is turned on and off in conjunction with the OFF operation, and the leakage detection circuit is disconnected from the main circuit by turning off the withstand voltage test switch, and the circuit breaker is forcibly tripped simultaneously. An earth leakage circuit breaker that has been proposed has been previously proposed and known (for example, see Patent Document 2), and a circuit diagram of the earth leakage circuit breaker is shown in FIG.

In FIG. 6, 1 is a main circuit conductor corresponding to each phase of R, S, and T, 2 is a main circuit contact of the circuit breaker, 3 is an opening / closing mechanism part of the main circuit contact 2, 4 is an opening / closing operation handle, and 5 is an excess This is an overcurrent trip device that detects a load current and a short-circuit current and trips the switching mechanism 3. An earth leakage trip device that detects the occurrence of a ground fault in the distribution line and trips the circuit breaker is a zero-phase circuit that detects an unbalanced current in the main circuit using the R, S, T phase main circuit conductor 1 as a primary conductor. A current transformer 6, a leakage detection circuit (electronic circuit including IC) 7 that detects the occurrence of a ground fault from the secondary output level of the zero-phase current transformer 6, and a trip that operates in response to the output from the leakage detection circuit 7 It consists of a coil unit 8.
Here, the leakage detection circuit 7 feeds the inter-phase voltage of the main circuit 1 through the power line 9 and the rectifier circuit 10 wired between the main circuit conductor 1 as its control power supply. A withstand voltage test switch 11 according to Patent Document 2 is connected. When conducting the insulation / withstand voltage test of the leakage breaker, the withstand voltage test switch 11 is turned off prior to the test to disconnect the leakage detection circuit 7 from the main circuit. 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.
Japanese Patent No. 3246562 JP 2004-199881 A

In order to equip the main unit case with a withstand voltage test switch for the single-layer earth leakage breaker described above, in addition to securing the switch installation space, operability and interlock with the circuit breaker switching mechanism Various restrictions are imposed on such aspects.
In other words, the earth leakage circuit breaker with the same size as the circuit breaker for wiring has more functional parts such as a zero-phase current transformer and earth leakage detection circuit than the circuit breaker for wiring. In practice, it is difficult to secure a space for newly installing a withstand voltage test switch because the main functional parts are tightly assembled without leaving any gaps. High reliability is also required for the operability of the withstand voltage test switch and the interlock function with the circuit breaker switching mechanism.
In this regard, in the earth leakage breaker disclosed in Patent Document 2, a small slide switch as a withstand voltage test switch is housed in the switch case and incorporated in the breaker body case, and then the switch is manually operated. The tip of the actuator provided on the slide operation type switch cover that opens and closes is opposed to the trip crossbar of the circuit breaker opening and closing mechanism to interlock between the withstand voltage test switch and the trip crossbar.

However, with this switch assembly structure, when the circuit breaker case cover is closed, the ON / OFF operation status of the withstand voltage test switch cannot be visually confirmed from the outside, and the switch is shut off at the switch OFF position. For the interlock mechanism that restrains and holds the trip crossbar of the detector at the latch release position, if the reset force is applied to the crossbar by the handle operation of the circuit breaker, the withstand voltage test switch receives this operation force and is turned off. There is also a problem in terms of function such as returning from the position to the ON position, and further improvement measures are desired from the viewpoint of increasing its reliability.
The present invention has been made in view of the above points, and based on the above-described leakage breaker with a withstand voltage test switch of Patent Document 2, the operability of the withstand voltage test switch and the visual observation of the ON / OFF operation position. Assembling structure to improve the interlock function with the circuit breaker opening and closing mechanism and to add an additional withstand voltage test switch without changing the layout of the main functional parts installed in the main body case of the circuit breaker The purpose of the present invention is to provide an earth leakage circuit breaker with a switch for withstanding voltage test having an improved arrangement.

In order to achieve the above object, according to the present invention, an earth leakage circuit breaker having an overcurrent protection function and a ground fault protection function, comprising a main circuit contact, a switching mechanism, an operating handle, an overcurrent tripping device, and a main body case. , And a manually operated withstand voltage test that incorporates an earth leakage trip device including a zero-phase current transformer and a leakage detection circuit, and enters and disconnects a power feeding circuit between the leakage detection circuit and the main circuit. With a switch equipped, the leakage test circuit is disconnected from the main circuit by turning off the withstand voltage test switch when conducting the insulation / withstand voltage test of the circuit breaker.
The withstand voltage test switch is constituted by an assembly unit of a switch body, a push / twist lock type switch operation unit for ON / OFF operation of a contact of the switch body, and an actuator linked to the switch operation unit, and is cut off. The actuator is housed in the main body case and mechanically interlocked with the operating end of the actuator facing the trip crossbar of the circuit breaker switching mechanism at this interior position, and the withstand voltage test switch is turned off via the actuator. The trip crossbar is driven to the latch release position to trip the circuit breaker, and at the same time, the crossbar is restrained and held at the latch release position (Claim 1).

In addition, according to the present invention, the specific assembly structure and arrangement of the withstand voltage test switch can be configured in the following manner.
(1) The switch operating portion of the withstand voltage test switch includes a push / twist operation type button, a cylindrical support guide for guiding the button, and a built-in support guide so that the button is directed to the OFF position. The button has an assembly with a drive spring that pushes up and biases, and the button has a projection protruding to the side of the support guide and facing the actuator, and the projection is inserted into the support guide to turn the button ON / OFF. A slit for guiding in the OFF direction and an engaging step portion for latching and holding the button at the ON position displaced in the circumferential direction from the terminal end of the guide slit are formed by notching.
(2) In the configuration of the above item (1), the actuator is linearly moved so that its base is slidably guided on the unit case of the withstand voltage test switch, and the protrusion of the button is placed on the actuator at this support position. They are connected to each other (claim 3).
(3) In the configuration of (1), the actuator is a pivot lever, one end of which is pivotally supported on the unit case of the withstand voltage test switch, and the protrusion of the button is opposed to the actuator at this support position. (Claim 4).
(4) Further, the withstand voltage test switch is surrounded by a zero-phase current transformer built in the main body case of the circuit breaker, a U-shaped main circuit conductor penetrating the current transformer, and a side wall of the main body case. An operation window hole is formed in the upper cover of the main body case so as to be disposed in the space and aligned with the operation end of the switch operation section.

According to the withstand voltage test switch having the above configuration, the following effects can be obtained.
(1) About the operation part of the withstand voltage test switch, the push / twist operation type tongue is locked at the ON / OFF position, so that the ON / OFF position can be reliably held and the ON / OFF position can be held. The ON / OFF state of the withstand voltage test switch can be confirmed at a glance by observing whether the head of the button protrudes or retracts from the operation window hole opened in the case cover of the circuit breaker.
(2) In addition to this switch ON / OFF operation, the actuator linked to the protrusion of the button of the switch operation unit restrains and holds the trip crossbar of the circuit breaker switching mechanism in the retracted position and the operating position. After the insulation / withstand voltage test of the earth leakage breaker is completed, the main circuit contact cannot be reset by operating the breaker handle unless the withstand voltage test switch is manually returned to the ON position. It is possible to reliably prevent a situation where the ground fault detection function does not work after resuming the use of the earth leakage circuit breaker due to forgetting to switch on the withstand voltage test switch.
(3) Furthermore, by utilizing the space between the side surface of the zero-phase current transformer incorporated in the main body case of the circuit breaker and the side wall of the main body case, the unitized withstand voltage test switch is accommodated and disposed. In addition, a withstand voltage test switch can be easily added without changing the layout of the earth leakage breaker, the circuit breaker for wiring, the common parts, and the functional parts.

Hereinafter, embodiments of the present invention will be described based on the examples shown in FIGS. In the illustrated embodiment, the same members corresponding to those in FIG.
First, FIG. 1 shows the overall configuration of an earth leakage breaker equipped with a withstand voltage test switch according to the present invention. In FIG. 1, reference numeral 12 denotes a main body case of an earth leakage circuit breaker having a divided structure of a lower case 12a and an upper cover 12b. The main body case 12 includes a main circuit contact opening / closing mechanism 3, an operation handle 4 described in FIG. , Overcurrent trip device 5, zero-phase current transformer 6, leakage detection circuit (printed board) 7, and functional parts such as a withstand voltage test switch 11 whose detailed structure will be described later, as well as each of U, V, and W The connection terminal 13 of the main circuit conductor 1 corresponding to the phase, the arc extinguishing chamber 14, and the trip crossbar 15 connected to the latch of the opening / closing mechanism 3 are arranged in a layout as shown in the figure. Further, the withstand voltage test switch 11 is located on the side of the zero-phase current transformer 6 and has a bent main circuit conductor 1 (a primary conductor of the zero-phase current transformer) that penetrates the zero-phase current transformer. And the outer wall of the main body case 11 are housed and deployed in a space surrounded by the periphery.

  Here, the withstand voltage test switch 11 includes a switch body 16 having a built-in switching contact mechanism, a switch operating section 17 for manually turning on / off the switching contact of the switch body 16, and the operation section 17 connected to the operating section 17. It has an assembly unit structure with the actuator 18 interlocked with the trip cross bar 15, and when the withstand voltage test switch 11 is manually turned OFF in the insulation / withstand voltage test of the earth leakage breaker as described above, it interlocks with this. Then, the actuator 18 drives the trip cross bar 15 to the latch release position to forcibly trip the earth leakage breaker. Further, the operation window hole 12c is opened in the upper cover 12b of the circuit breaker body case 12 in alignment with the switch operation portion 17 of the withstand voltage test switch 11, and a driver (screwdriver) is used from the outside as described later. Thus, the withstand voltage test switch 11 is turned ON / OFF.

Next, the detailed structure of the withstand voltage test switch 11 will be described with reference to FIGS. That is, the withstand voltage test switch 11 has a unit structure in which the switch case 16, the switch operating portion 17, and the actuator 18 are provided in the unit case 19. The unit case 19 is provided with the circuit breaker body case 12 shown in FIG. In the lower case 12a, it is bent in a U-shape and inserted from above into a space between the primary conductors that penetrates the zero-phase current transformer 6, and is arranged at a fixed position.
Here, the switch operation unit 17 is described in detail in a push / twist operation type button 17a, a cylindrical support guide 17b for inserting the button 17a and guiding it in the vertical direction, and an exploded view of FIG. It consists of an assembly with a drive spring 17c that is built in a support guide and pushes and urges the button toward the OFF position, and protrudes to the side of the support guide 17b on the peripheral surface of the button 17a so as to confront the actuator. The protrusion 17d has a protrusion 17d, and the protrusion 17d is inserted into the support guide 17b so as to guide the button 17a between the ON / OFF positions, and is displaced in the circumferential direction from the lower end of the guide slit 17e. An engagement step portion 17f that latches and holds the protrusion 17d of the button is formed in the cut-off position. A groove for inserting a driver (screwdriver) is formed on the top end face of the button 17a.

The actuator 18 is arranged on the upper surface of the unit case 19 side by side with the switch operation unit 17, and its operation end 18 a is opposed to the trip crossbar 15 (see FIG. 1) of the circuit breaker. 18b is inserted into a guide rail groove 19a formed on the upper surface side of the unit case 19, and is guided and supported in the operation direction. At this position, a screen-like operation plate (pad plate) 18c extending upward from the base portion 18b is attached to the button. The protrusion 17d of 17a is connected in opposition.
Further, as shown in FIG. 4, the switch body 16 has a pair of leaf spring contact pieces 16b that stand upright with the lower ends fixed to the left and right connection leads 16a, and a contact between the contact pieces 16b. The movable piece 16c is an assembly with an insulating movable piece 16c arranged to turn the contact ON / OFF, and the movable piece 16c is rotatably connected to the button 17a of the switch operating portion 17 through a joint. An insulating cover that moves up and down together with the button 17 a is provided on the open surface of the unit case 19 shown in FIG. 2 so as to cover the contact mechanism of the switch body 16.

  With the above configuration, when the button 17a of the switch operation unit 17 is fully pushed downward and twisted counterclockwise, the movable piece 16c of the switch body 16 is lowered and the switching contact of the contact piece 16b is turned on (FIG. 4). At the same time, the protrusion 17d of the button 17a is hooked on the lower surface of the engagement step 17 formed on the support guide 17b and locked in this ON position. Further, the protrusion 17d moves backward from the operation plate 18c of the actuator 18 to release the restraint of the actuator 18. On the other hand, when the button 17a is twisted clockwise at the ON position in FIG. 2A to disengage the projection 17d from the engaging step 17f of the support guide 17b, the button 17a is a spring of the drive spring 17c (see FIG. 3). The movable piece 16c of the switch main body 16 is moved upward by receiving the force and is moved between the left and right contact pieces 16b (see FIG. 4B). As a result, the switching contact is released and the switch is turned off. At the same time, the projection 17d of the button 17a pushes and drives the actuator 18 in the operation direction, and at the same time, the projection 17d fits into the slit 17e of the support guide 17b and restrains the actuator 18 at the pushing position.

Next, an operation procedure and an operation function of the withstand voltage test switch 11 at the time of the insulation / withstand voltage test will be described for the earth leakage breaker equipped with the withstand voltage test switch 11 having the above configuration in the main body case 12 of the breaker.
That is, in a normal use state of the earth leakage circuit breaker, the withstand voltage test switch 11 is pushed in the button 17a of the operation unit and is held in the switch ON state of FIG. 2A, and the actuator 18 is restrained by the projection 17d. The circuit breaker is free for the trip crossbar 15 of the circuit breaker. If the earth leakage breaker is ON in this state, the interphase voltage of the main circuit is supplied to the earth leakage detection circuit 7 through the withstand voltage test switch 11 as described in FIG. On the other hand, when conducting the insulation / withstand voltage test of the earth leakage circuit breaker, a screwdriver is inserted into the operation window 12c opened in the upper cover 12b of the circuit breaker shown in FIG. 1, and the button 17a is twisted clockwise. In the state of (b), the contact of the switch body 16 is turned off to disconnect the leakage detection circuit 7 from the primary conductor 1 of the circuit breaker, and at the same time, the actuator 18 protruding in the operation direction via the protrusion 17d of the button 17a. The trip crossbar 15 is driven to the latch release position to trip the circuit breaker, and the trip crossbar 15 is restrained and held at this position, thereby preparing for the insulation / withstand voltage test.

When the withstand voltage test switch 11 is manually returned to the ON position after completion of the insulation / withstand voltage test (see FIG. 2A), the restriction of the trip crossbar 15 by the actuator 18 is released. Therefore, by returning the handle 4 (see FIG. 1) of the circuit breaker stopped at the trip position to the reset position and then turning it on, the main circuit contact 2 (see FIG. 6) is closed and the leakage occurs. The circuit breaker returns to normal use. In this case, unless the withstand voltage test switch 11 is returned to the ON position, even if the operation handle 4 is moved from the trip position to the OFF position, the opening / closing mechanism 3 is not reset. It cannot be thrown in. As a result, it is possible to avoid the trouble that the ground fault detection of the earth leakage breaker and the earth leakage protection function do not work due to forgetting to put in the withstand voltage test switch 11.
Next, an application embodiment corresponding to claim 4 of the present invention will be described with reference to FIGS. That is, in the above-described embodiment shown in FIG. 2, the actuator 18 assembled to the withstand voltage test switch 11 is fitted and supported in a guide rail groove 19a formed in the upper portion of the unit case 19 as a linear motion type slider. . On the other hand, in the embodiment of FIG. 5, the actuator 18 is a rotary lever, the rear side of the actuator 18 is curved in a U shape so as to bypass the peripheral area of the switch operating portion 17, and the support pin 18d is Further, a projection 18e is provided on the unit case 19 so as to face the projection 17d of the button 17a along the rear of the operation piece 18c.

With the above configuration, when the withstand voltage test switch 11 is in the ON state, as shown in FIG. 5A, the protrusion 17d of the button 17a that is locked in the ON position pushes back the protrusion 18e, thereby It is held in the retracted position (the same state as in FIG. 2A).
Here, in the insulation / withstand voltage test of the earth leakage circuit breaker, when the button 17a is twisted clockwise to turn off the withstand voltage test switch 11 as described with reference to FIG. 18 is driven to protrude in the operation direction, whereby the actuator 18 rotates about the support pin 18d as a fulcrum, and the operating end of the tip drives the trip crossbar 15 (see FIG. 1) to the latch release position, thereby closing the circuit breaker. Make trip operation. The procedure of the return operation of the withstand voltage test switch 11 performed after the test is the same as in the embodiment described with reference to FIG.

The perspective view showing the whole structure of the earth-leakage circuit breaker with a switch for a withstand voltage test corresponding to the Example of this invention FIG. 2 is a structural diagram of a withstand voltage test switch in FIG. 2 is an exploded perspective view of the switch operation unit and the actuator in FIG. FIG. 3 is a schematic diagram showing the structure and operation of the switch body in FIG. FIG. 3 is a configuration diagram of a withstand voltage test switch according to an embodiment different from FIG. 2, in which (a) and (b) are external perspective views showing ON and OFF states of the switch, respectively. Circuit diagram of earth leakage breaker with switch for withstanding voltage test

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main circuit conductor 2 Main circuit contact 3 Opening and closing mechanism 4 Operation handle 5 Overcurrent trip device 6 Zero phase current transformer 7 Leakage detection circuit 8 Trip coil unit 11 Withstand voltage test switch 12 Body case 12b Upper cover 12c Operation window hole 15 Trip crossbar 16 Switch body 17 of switch for withstanding voltage test Switch operation part 17a Button 17b Support guide 17c Drive spring 17d Projection part 17e Slit 17f Engagement step part 18 Actuator

Claims (5)

An earth leakage circuit breaker with overcurrent and ground fault protection, including a main circuit contact, a switching mechanism, an operation handle, an overcurrent trip device, a zero-phase current transformer and an earth leakage detection circuit in the main body case Equipped with a disconnecting device and equipped with a manually operated withstand voltage test switch that turns on and off the feeder circuit wired between the leakage detection circuit and the main circuit. In the case where the leakage test circuit is disconnected from the main circuit by turning off the voltage test switch,
The withstand voltage test switch is constituted by an assembly unit of a switch body, a push / twist lock type switch operation unit for ON / OFF operation of a contact of the switch body, and an actuator linked to the switch operation unit, and is cut off. The actuator is housed in the main body case and mechanically interlocked with the operating end of the actuator facing the trip crossbar of the circuit breaker switching mechanism at this interior position, and the withstand voltage test switch is turned off via the actuator. The circuit breaker is tripped by driving the trip crossbar to the latch release position, and at the same time, the crossbar is restrained and held at the latch release position. The earth leakage circuit breaker according to claim 1, wherein the switch operating portion of the withstand voltage test switch includes a push / twist operation type button, a cylindrical support guide for guiding the button, and a built-in support guide. The button comprises a drive spring that pushes and urges the button toward the OFF position, the button has a protrusion protruding sideways and facing the actuator, and the protrusion is inserted into the support guide to push the button. An earth leakage circuit breaker characterized in that a slit for guiding in the ON / OFF direction, and an engaging step portion for latching and holding the button at the ON position displaced in the circumferential direction from the terminal end of the guide slit, are cut out. 3. The earth leakage circuit breaker according to claim 2, wherein the actuator is linearly operated, and its base is slidably guided and supported on the unit case of the withstand voltage test switch, and the protrusion of the button is provided on the actuator at this support position. An earth leakage circuit breaker characterized by being connected and connected. 3. The earth leakage circuit breaker according to claim 2, wherein one end of the actuator is pivotally supported on the unit case of the withstand voltage test switch, and the protrusion of the button is opposed to the actuator at the support position. An earth leakage circuit breaker characterized by having been made. The earth leakage circuit breaker according to claim 1, wherein the withstand voltage test switch includes a zero-phase current transformer built in the main body case of the circuit breaker, a U-shaped main circuit conductor penetrating the current transformer, and a side wall of the main body case. An earth leakage circuit breaker characterized in that an operation window hole is opened in the upper cover of the main body case so as to be arranged in a space surrounded by a space and aligned with the operation end of the switch operation unit.

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