KR100898469B1 - Earth leakage breaker - Google Patents

Abstract

assignment

With respect to the megger test switch mounted on the earth leakage breaker, the operation structure and interlock function with the switchgear mechanism are improved, and the assembly structure thereof is further improved so that the switch can be additionally equipped without changing the layout of the breaker main parts.

Resolution

Mount the main functional parts of the circuit breaker in the main body case, and then add a mega test switch to the power supply circuit between the circuit breaker detection circuit and the main circuit. In an earth leakage circuit breaker configured to be separated from the main circuit, an actuator in which a megger test switch is connected to the switch main body 20 and one end to an operating rod of the switch main body, and the other end is replaced by a trip crossbar 15 of the breaker opening / closing mechanism. In addition to the assembly unit 18 of the seesaw lever 21, a push-and-twist lock-type pushbutton 19 is provided on the cover 12b of the main body case against the actuator 21, The push-and-twist operation of the pushbutton turns off the switch body through the actuator, and drives the trip crossbar to the latch release position to open the breaker. And, the support bound an actuator at the same time via the push-button in the operating position.

Description

Earth leakage breaker {EARTH LEAKAGE BREAKER}

1 is an explanatory view of the operation and function of the mega test switch unit according to an embodiment of the present invention, (a) and (b) is the operation of the push button and actuator corresponding to the ON and OFF of the mega test switch, respectively The perspective view of the principal part which shows a state.

Fig. 2 is a detailed structural diagram of a mega test switch unit and a push button shown in Fig. 1, (a) is an exploded perspective view of each component, and (b) is a perspective view seen from the back side of the cylindrical guide in (a).

Figure 3 is a perspective view showing the internal structure of the circuit breaker as a whole equipped with a switch unit and a push button for the mega test of Figure 1 in the main body case.

Fig. 4 is a diagram showing the internal structure and operation of the switch main body in Fig. 2, wherein (a) and (b) are operation state diagrams of ON and OFF of the switch, respectively.

5 is a circuit diagram of a switch leakage circuit breaker for mega test.

Fig. 6 is a perspective view showing the entire structure of a ground fault breaker equipped with a conventional mega test switch.

(Explanation of symbols for the main parts of the drawing)

1: Main circuit 2: Main circuit contact

3: opening mechanism 4: steering wheel

5: overcurrent external device 6: image transformer

7: earth leakage detection circuit 8: trip coil unit

12: body case 12a: case

12b: Cover 12c: Top Cover

12c-1: Operation window hole 13: Main circuit conductor

15: trip crossbar 18: switch unit for mega test

19: push button 19b: protrusion

20: switch body 20a: switch case

20b: fixed electrode 20c: movable contactor

20d: movable contact holder 21: actuator

21d: gauze spring 22: unit case

22c: engagement convex 23: cylindrical guide

23a: slit 23b: engagement end

24: return spring

Technical field

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an earth leakage circuit breaker applied to a low voltage distribution system, and more particularly, a mega test for separating an earth leakage detection circuit from a main circuit when mounted on a circuit breaker and performing an insulation test and a withstand voltage test (megger test). An assembly structure of a megger test switch.

Background technology

In recent years, the earth leakage breaker has the main circuit case of the wiring breaker and the earth leakage breaker to have the same external size in order to improve the feeling on the consumer side. have.

The earth leakage circuit breaker is a ground fault circuit for detecting an unbalanced current in the main circuit using the main circuit as a primary conductor, as well as an overcurrent protection component such as a circuit breaker, and a ground fault from the secondary output level of the video current transformer. ) An earth leakage detection circuit (electronic circuit including an IC) that detects an accident occurrence, and a trip coil unit that receives an output signal of the earth leakage detection circuit and trips an opening / closing mechanism of the circuit breaker. Moreover, as a control power supply of the said earth leakage detection circuit, the voltage between phases of a main circuit is rectified, and it is made to feed an electric leakage detection circuit.

On the other hand, in the earth leakage breaker, the insulation strength between phases of the main circuit is prescribed by the standard, and insulation strength and withstand voltage test (megger test) are performed for each product to measure the insulation strength. This megger test is performed by applying a test voltage between the phases of the main circuit terminals while the main circuit contact of the earth leakage breaker is open (OFF), and the test voltage depends on the rated voltage of the earth leakage breaker. For example, the test voltage of an earth leakage breaker with a rated voltage of 400 to 600V is specified as 2500V.

By the way, when performing the megger test of an earth leakage circuit breaker, if a test voltage is applied with the said earth leakage detection circuit connected between the phases of a main circuit, the earth leakage detection circuit which is an electronic circuit will be destroyed by a test voltage, In the city, it is necessary to keep the ground fault detecting circuit away from the main circuit. Therefore, in order to simplify the mega test at the point of use of the earth leakage breaker, a test switch (megger test switch) is additionally installed in the main body case of the earth leakage breaker, and the earth leakage detection circuit is It is known to disconnect the power supply circuit (see Patent Document 1, for example).

In addition, an earth leakage circuit breaker in which a main circuit contact is opened by mechanically forcibly tripping an opening / closing mechanism of the circuit breaker in conjunction with the OFF operation of the megger test switch has been proposed (for example, Patent Document 2). Fig. 5 shows a circuit diagram of the circuit breaker for a three-phase three-wire circuit as an example and an assembly structure of the circuit breaker in Fig. 6.

First, in Fig. 5, 1 is a main circuit corresponding to each phase of R, S, and T, 2 is a main circuit contact, 3 is an opening and closing mechanism part of the main circuit contact 2, 4 is an operation handle, and 5 is a main circuit ( It is an overcurrent external device which detects the overload current and the short circuit current of 1) and trips the switching mechanism 3. In addition, the ground fault external device which detects the occurrence of a ground fault in the distribution path and trips the opening / closing mechanism 3 includes an image current transformer which detects an unbalanced current using the main circuit 1 of each of R, S, and T as primary conductors. 6), an earth leakage detection circuit (electronic circuit including an IC) 7 for detecting the occurrence of a ground fault from the secondary output level of the video current transformer 6, and receiving and outputting an output signal from the earth leakage detection circuit 7; It consists of a trip coil unit 8 which trips the mechanism 3.

Here, the ground fault detection circuit 7 supplies power between phases of the main circuit through the power supply line 9 and the rectifier circuit 10 wired between the main circuit 1 of each phase as its control power supply. A mega test switch (withstand voltage test switch) 11 is openly connected to the power supply circuit. And when performing the megger test of an earth leakage breaker, prior to a test, the MEGA test switch 11 is OFF manually, and the earth leakage detection circuit 7 is disconnected from the main circuit, and a circuit breaker is interlocked with this switch OFF operation. Is forced to mechanically trip to open the main circuit contacts. In the illustrated example, the phase voltages of the R, S, and T phases of the main circuit are DC-converted and supplied. However, the voltage between the R-T phases and the phases may be supplied to the ground fault detection circuit 7.

Next, the structure of the said earth leakage breaker equipped with the switch for mega test is shown in FIG. In FIG. 6, 12 is a main body case (molded resin molded article) of the circuit breaker which consists of a case 12a and the cover 12b, and the main body case 12 has the toggle link type opening / closing mechanism 3, and an operation handle. (4), the overcurrent external device (5), the image current transformer (6), and the earth leakage detection circuit (7), trip coil unit (8), mega test switch (11) as shown in the layout (layout) as shown It is. In the case 12a, a space corresponding to each of the R, S, and T phases is divided into partition walls between the phases. The device 15 is a trip crossbar which receives the mechanical output signals of the overcurrent external device 5 and the trip coil unit 8, releases the latch of the opening and closing mechanism 3, and trips the trip.

Here, the ground fault detecting circuit 7 accommodates the printed plate in the unit case, and then includes a space surrounded by the “U-shaped” primary conductor passing through the image transformer 6 and the image current transformer and the left side wall of the case 12a. To accommodate. On the other hand, the megger test switch (slide control switch) 11 is an actuator 16 which is inclined cam shape on a rod which is connected to the movable contact holder and pulled upward from the switch case, and And a “U-shaped” main circuit conductor penetrating the video current transformer 6 and the video current transformer on the side opposite to the receiving position of the ground fault detection circuit 7, with an operation knob 17 formed at the front end thereof. It is arrange | positioned in the recessed space enclosed by the side wall of case 12a. And in this built-in position, the said operation knob 17 is made to face the switch operation hole 12b-1 opened to the cover 12b of the main body case 12, and the tip of the actuator (incline cam) 16 is overcurrent. The trip crossbar 15 is replaced by an operation end (armature) of the outer device 5. In addition, the trip coil unit 8 is arrange | positioned at the side of the operation handle 4 arrange | positioned in the center of the main body case 12, In this assembly layout, the main circuit conductor 13, the mega test switch 11, Internal wiring is provided between the ground fault detection circuit 7 and the trip coil 8 (see FIG. 5).

In addition, when the circuit breaker is equipped with the circuit breaker, the cover 12b of the main body case 12 is installed in the van in the longitudinal position facing forward, and the operation handle 4 is attached to the door panel of the switchboard. It protrudes more than the opened window hole and opens and closes from outside.

In the above-described configuration, when the MEGA test of the earth leakage breaker is carried out, the above operation knob 17 is pulled out from the front of the main body case 12 and the MEGA test switch 11 is turned OFF to operate the earth leakage detection circuit 7. Power supply circuit is disconnected. At the same time, the actuator 16 kicks the operating end (amateur) of the outer device 5 to drive the trip crossbar 15 to the latch release position. Thereby, the opening-closing mechanism 3 mechanically trips, and the main circuit contact 2 (refer FIG. 5) turns OFF.

Moreover, in order to return an earth leakage breaker to a normal use state after completion | finish of a megger test, the said operation knob 17 is pushed in and the megger test switch 11 is returned to an ON position. As a result, the ground fault detecting circuit 7 is connected between the phases of the main circuit 1. At the same time, the actuator 16 releases the trip crossbar 15. In this state, when the operation handle 4 is dropped to the reset position and then switched to the ON position, the main circuit contact 2 closes to return the earth leakage breaker to the normal use state.

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-319135 (Fig. 1)

Patent Document 2: Japanese Patent Application Laid-Open No. 2004-349063 (FIGS. 1 to 4)

By the way, the above-mentioned circuit breaker is equipped with the mega test switch 11 inside the main body case 12, in addition to securing the installation space of the switch, as well as the assemblability and operability of the switch and the breaker opening / closing mechanism. There are various problems to be solved in terms of interlock function.

In other words, the circuit breaker for wiring and the circuit breaker having the same external size have more functional parts such as the video current transformer 6 and the ground fault detection circuit 7 than the circuit breaker for wiring, and the main body case 12 has various main functions. Most parts are tightly assembled without any remaining space. Equipped with the mega test switch 11 in the remaining space of the main body case 12 under such conditions, in addition to the compact structure of the mega test switch 11, the operability of the switch and the breaker opening and closing mechanism and The high reliability of the interlock function is required.

In this regard, in the conventional ground fault circuit breaker disclosed in Patent Document 2 (see FIG. 6), the switch 11 for the mega test is upward from the slide main switch body built in the circuit breaker main body case 12. Directly apply the operating force to the operation knob 17 of the drawn rod to open and close it, and replace the tip of the inclined cam-shaped actuator 16 formed on the rod by replacing the trip crossbar 15 of the breaker opening / closing mechanism. Is interlocking.

However, in this assembly structure, if an excessive force is applied to the operation knob 17 of the mega test switch 11, and it draws out violently and press-fits, there exists a possibility that a switch main body may be damaged.

In addition, the actuator 16 formed in the operation rod is a shank-type inclined cam, whereas the trip crossbar 15 of the breaker is a tilt-type lever. For this reason, even in the state which pulled out the rod of the megger test switch 11 at the time of a megger test and tripped the earth leakage breaker, during the megger test, the operation handle 4 of the breaker was accidentally reset and the trip crossbar 15 was carried out. When a force in the reset direction is applied to the actuator, the actuator (incline cam) 16 is pushed down by the trip crossbar, and the mega test switch 11 returns from OFF to ON. As a result, there is also a problem of safety that a high test voltage is applied to the ground fault detection circuit 7, and a new improvement is necessary even in order to increase the reliability of the interlock function.

The present invention has been made in view of the above points, and on the basis of the above-mentioned ground fault circuit breaker with a switch for a mega test, the assembly and operability of a switch for a mega test and an interlock function with a breaker opening and closing mechanism are improved. It is an object of the present invention to provide an earth leakage circuit breaker with an improved assembly structure so that a mega test switch can be additionally equipped without changing the layout of the main functional parts built into the main body case of the circuit breaker.

In order to achieve the above object, according to the present invention, an earth leakage circuit breaker having an overcurrent and ground fault protection function includes a main circuit contact, an opening / closing mechanism, an operation handle, an overcurrent external device, and an image current transformer and an earth leakage detection circuit in a main body case. Equipped with a manual test switch for inserting and disconnecting a feeder circuit wired between the ground fault detection circuit and the main circuit, and breaking the circuit; In that the ground fault detection circuit is separated from the main circuit by turning off the switch.

The MEGA test switch comprises an assembly unit of an actuator in which the switch main body and one end are connected to the operation rod of the switch main body and the other end is replaced with a trip crossbar of the breaker opening / closing mechanism. A push-and-twist lock-type push button for turning the switch body on or off against the actuator is mounted on the cover of the breaker body case, and the push-and-twist operation of the push button causes the The switch body is turned OFF, the trip crossbar is driven to the latch release position to trip the breaker, and at the same time, the push button is locked to this position to restrain the trip crossbar at the latch release position (claim 1). Each of the substructures may be formed in a specific embodiment such as the following description. The.

(1) The switch main body of the megger test switch includes a switch case made of an insulating material partitioned between the poles, a fixed electrode arranged on the bottom side of the switch case using a pair of left and right contacts as a jaw. And an assembly of an entangled movable contactor disposed opposite to the fixed electrode and a movable contactor holder which collectively supports the movable contactor of each pole and pulls out its operation end above the switch case. (Claim 2).

(2) The actuator of the megger test switch uses a seesaw lever in combination with a biasing spring as a base, and an operation end of the switch main body at one arm end extending on both sides of the shaft portion. The engaging part is formed, the arm end of the other side facing the front end of a pushbutton is bent, and it is set as the structure which replaced the operation end of a trip crossbar (claim 3).

(3) The push button is supported by being inserted into the cylindrical guide formed on the cover of the circuit breaker main body in combination with the return spring, and on the main surface of the cylindrical guide. And a slit in the longitudinal direction for guiding the pushbutton in the ON or OFF direction, and extending from the lower end of the slit in the circumferential direction to engage the pushbutton in the push-and-twist lock position. To form a court (claim 4).

(4) In the configuration of the preceding (1), between the video current transformer having the mega test switch mounted on the main body case of the circuit breaker and the side wall of the main body case, the concave surrounded by the U-shaped main circuit conductor passing through the video current transformer. In the unit case supporting the switch main body and the actuator, the engagement convex part engaging the engaging groove formed on the upper edge of the side wall of the main body case and holding the unit assembly at a predetermined position is provided. 5).

(5) In the configuration of the preceding (3), the top cover is placed on the cover upper surface of the circuit breaker main body case, and the operation window hole of the push button on the top cover is aligned with the operation end of the push button attached to the cover. Is opened (claim 6).

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on the Example shown to FIGS. In addition, in the Example shown to FIGS. 1-4, the same code | symbol is attached | subjected to the same member corresponding to FIG. 5 and FIG.

First, the whole structure of the earth leakage breaker equipped with the assembly unit of the mega test switch by this invention is shown in FIG. In the figure, reference numeral 12 denotes a main body case of an earth leakage breaker which is divided into a case 12a, a cover 12b, and a top cover 12c. Here, in the case 12a of the main body case 12, the opening / closing mechanism 3, the operation handle 4, the overcurrent external device 5, the video current transformer 6, and the earth leakage detecting circuit 7 are similarly to FIG. The trip crossbar 15 connected to the latch of the trip coil unit 8, the main circuit conductor 13, the arc-extinguishing chamber 14, and the opening / closing mechanism 3 is mounted. In addition, the U-shaped main circuit conductor (R phase) in which the megger test switch unit 18 according to the present invention is interposed between the video current transformer 6 and the side wall of the case 12a, and is interposed on the annular core of the video current transformer. It is accommodated in the concave space surrounded by the (13). In addition, the cover 12b has a push button 19 for turning on or off the mega test switch, and the operation window hole 12c-1 corresponding to the push button 19 is opened in the top cover 12c. have.

Next, the detailed structures of the above-described mega test switch unit 18 and the push button 19 will be described with reference to the exploded view of FIG. First, the switch unit 18 is composed of an assembly of a switch body 20, an actuator 21, and a unit case 22, and the switch body 20 and the actuator 21 are described later in the unit case 22. It is assembled as follows.

Here, as shown in FIG. 4, the switch main body 20 switches the box-shaped switch case (mold resin case) 20a by which the inside of a case is partitioned by the partition, and a pair of left and right contacts as a pair. The switch case is collectively supported by the fixed electrode 20b assembled on the lower side of the case 20a, the entangled movable contactor 20c facing the fixed electrode 20b, and the movable contactor 20c of each pole. It consists of the movable contact holder 20d drawn out upward from 20a. The hook-shaped handle part 20d-1 which is an operation rod is formed in the front-end | tip of the movable contact holder 20d.

In the above configuration, when the movable contact holder 20d is press-fitted in the direction of the arrow A in Fig. 4A, the movable contact 20c comes in contact with the fixed electrode 20b to be switched on. Further, when the movable contact holder 20d is pulled up in the direction of an arrow B in Fig. 4B, the movable contact 20c is opened from the fixed electrode 20b and switched off.

And this switch main body 20 is penetrated from the side to the switch support edge part 22a formed in the middle position of the unit case 22, as shown in FIG. Fixedly coupled. 25 is a lead wire drawn out from the switch case 20a by wiring to the fixed electrode 20b of the switch main body 20.

In addition, engagement projections 22c are formed on the outer surface of the unit case 22. As shown in FIG. 3, in the state where the mega test switch unit 18 is mounted on the main body case 12 of the circuit breaker, the engagement protrusion 22c is placed on the upper edge of the side wall of the case 12a. It is made to fit into the notch-formed engagement groove 12a-1, and to carry out positioning support in the fixed position.

On the other hand, the actuator 21 uses a seesaw lever whose arm extends from side to side with the shaft portion 21a as a base as a base, and combines a spring (torsion coil spring) 21d with this, and the shaft portion 21a. ) Is assembled to the bearing portion 22b provided in the top of the unit case 22.

Here, at the front end of the lever arm extending from the shaft portion 21a to the right side, the engagement arm portion 21b on which the movable contact holder 20d drawn upward from the switch body 20 hangs on the handle portion 20d-1. Is formed. Further, the lever arm extending from the shaft portion 21a to the left side is such that the tip portion 21c is bent upward, and the tip portion 21c is replaced by the trip crossbar 15 of the breaker as described later. . Further, the biasing spring 21d assembled to the lever of the actuator 21 turns on the movable contact holder 20d (see FIG. 4) of the switch main body 20 by applying the lever clockwise in the free state of the actuator. Drive in position.

On the other hand, the push button 19 is a push-and-twist lock-type button, which is press-fitted and supported by a return spring (compression coil spring) in a cylindrical guide 23 integrally formed so as to protrude toward the back side of the cover 12b of the main body case. In this position, the tip of the push button 19 faces the lever arm (left side) of the actuator 21.

Here, a groove for inserting a driver (tool) is formed in the upper head of the push button 19, and the engaging guide 19a formed at the distal end of the shaft portion extending downward from the head has a cylindrical guide 23. It is supported by a snap fit at the tip of the head). Further, a guide projection 19b is formed on the head main surface of the push button 19, and a corresponding slit for longitudinal guidance on the main surface of the cylindrical guide 23 corresponds to the projection 19b. 23a) and the engaging end 23b extending in the circumferential direction from the end of the slit 23a is formed. In this structure, the push button 19 is guided in the push direction, and the push button 19 is held at the locked position by the push and twist operation.

Next, referring to Figs. 1A and 1B, the functions and operations of the mega test switch unit 18 and the push button 19 will be described. 1A and 1B show a state in which the mega test switch unit 18 and the push button 19 described in FIG. 2 are attached to a main body case of a breaker. (a) and (b) show the ON and OFF states of the mega test switch, respectively.

That is, in the normal use state of the earth leakage breaker, as shown in Fig. 1 (a), the push button 19 receives the spring force of the return spring 24 and waits for retreat at the position pressed up above the cylindrical guide 23. have. In this state, the actuator 21 of the mega test switch unit 18 tilts clockwise by the spring force of the biasing spring 21d (see FIG. 2), and moves the movable contact holder 20d of the switch body 20 ( 4) is pressed down and kept in the switch ON state. In addition, the bent front end 21c of the actuator 21 retreats from the operation end of the trip crossbar 15. As a result, the voltage between the phases of the main circuit 1 shown in FIG. 5 is supplied to the ground fault detecting circuit 7.

On the other hand, when performing the megger test of an earth leakage breaker, the push button 19 is pushed in the direction of arrow A using a tool, such as a screwdriver, from the outside and twist-operated. By this operation, the tip of the push button presses the actuator 21 of the mega test switch unit 18 and tilts the lever counterclockwise, while the push button itself is a projection 19b on its head side. Is engaged with the engagement end 23b formed in the cylindrical guide 23, and is latched and supported in the push position by receiving the spring force of the return spring 24. As shown in FIG. Further, the actuator 21 is also tilted in the counterclockwise direction, and then pressed by the push button 19 to be restrained and supported at the tilted position.

As a result, as shown in Fig. 4B, the switch main body 20 is pulled up in the direction indicated by the arrow B by the movable contact holder 20d, and the contact is turned OFF. Disconnect the circuit. Further, the lever tip portion 21c of the actuator 21 kicks the operating end of the trip crossbar 15, and drives the trip crossbar to the latch release position in the direction of the arrow C to mechanically trip the opening and closing mechanism of the breaker. In addition, the main circuit contact 2 of FIG. 5 opens, thereby preparing the mega test. In this state, even if the handle 4 (see Fig. 3) of the circuit breaker is reset by mistake, since the trip crossbar 15 is restrained at the latch release position, the main circuit contact cannot be inserted. In this way, a megger test can be performed appropriately.

After the end of the megger test, the push button 19 is twisted in the opposite direction to the above, and the projection 19b is removed from the engaging end 23b of the cylindrical guide 23, and the push button 19 returns to the return spring ( It pops upward with the spring force of 24) and releases the restraint of the actuator 21. Thereby, the lever of the actuator 21 oscillates clockwise by the spring force of the biasing spring 21d, returns to the state of FIG. 1A, the switch main body 20 is turned ON, and the trip crossbar. The restraint of (15) is also released.

Therefore, by returning the handle 4 (see FIG. 3) of the breaker stopped at the trip position to the reset position once and then turning it into the ON position, the main circuit contact 2 (see FIG. 5) closes and the ground fault breaker is normally operated. Return to use state. In this case, as long as the push button 19 is not returned, the opening / closing mechanism part 3 is not reset even when the operation handle 4 is reset, and thus the main circuit contact 2 cannot be inserted. In this way, it is possible to avoid trouble that the ground fault detection and the ground fault protection function of the ground fault breaker do not work by forgetting to turn on the mega test switch.

By the above structure, the effect of the following description can be achieved.

(1) The switch for mega test was comprised by the assembly unit of a switch main body and an actuator, and also this unit was isolate | separated, and it attached to the cover of a circuit breaker main body case in combination with a return spring and a push-and-twist lock-type pushbutton. As a result, even if an excessive operation force is applied to the push button, the excessive operation force is received by the cover of the main body case, and thus the mega test switch main body can be protected from destruction safely.

(2) Here, the actuator described above was used as a seesaw lever, so that the bent end of the lever arm was replaced by the operating end of the trip crossbar of the breaker. Thereby, in conjunction with the OFF operation of the megger test switch main body by the push operation of a push button, a tripping crossbar can be reliably driven to the latch release position from the side, and a circuit breaker can be mechanically tripped.

(3) In addition, the push crossbar is held in the cylindrical guide of the main body case cover at the push and twist lock position at the time of OFF operation of the mega test switch, so that the trip crossbar is secured to the latch release position through the actuator. It can support restraint. In addition, unless the push button is set back to the ON position, even if the handle of the breaker is to be reset, the main circuit contact of the breaker cannot be reset because the trip crossbar is constrained to the latch release position. As a result, the ground fault detection function is activated after the earth leakage breaker is restarted due to the misoperation of the handle during the megger test of the earth leakage breaker. It is possible to reliably avoid the situation of not doing so, thereby improving the reliability of the switch function.

(4) In addition, by utilizing the remaining space between the side of the video current transformer mounted on the circuit breaker and the side wall of the main body case, the unit for the mega test switch unit is accommodated therein so as to provide the The main body case can easily be equipped with a switch unit for a mega test without changing the layout. In addition, by fitting the engagement convex portion provided in the unit case of the mega test switch to the engagement groove formed at the upper edge of the side wall of the main body case, the switch unit can be positioned at a predetermined position and supported between the main body case and the cover.

Claims (6)

An earth leakage circuit breaker with overcurrent and ground fault protection, which includes a main circuit contact, an opening / closing mechanism, an operation handle, an overcurrent trip device, and a current transformer and an earth leakage detection circuit in a main body case. And a manually operated megger test switch for turning on and off a power supply circuit wired between the ground fault detection circuit and the main circuit. In an earth leakage circuit breaker in which the earth leakage detection circuit is separated from the main circuit by turning off the megger test switch, The megger test switch is composed of an assembly unit with an actuator in which a switch main body and one end are connected to an operating rod of the switch main body and the other end is replaced with a trip crossbar of a breaker opening and closing mechanism. A push-and-twist locking type push button is mounted on the cover of the breaker main body case to be mounted in the main body case and to turn on or off the switch main body opposite the actuator. The push-and-twist operation of the pushbutton causes the switch body of the megger test switch to be turned off through an actuator, and the trip crossbar is driven to the latch released position to trip the breaker. Locked in position to retain the trip crossbar in the latch release position A circuit breaker that. The method of claim 1, The switch body of the megger test switch includes a switch case made of an insulator partitioned between the poles, a fixed electrode arranged on the bottom side of the switch case with a pair of left and right contacts, and the fixed electrode. A bridge-shaped movable contactor disposed opposite to the upper side of the switch, and an assembly of movable contactor holders which collectively support the movable contactors of the respective poles and pull out the operation end thereof above the switch case. Earth leakage breaker. The method of claim 1, The actuator of the megger test switch uses a seesaw-type lever in combination with a biasing spring as a base, and an operating end of the switch main body at one arm end extending on both sides of the shaft portion. A circuit breaker characterized in that the engaging portion is formed, and the female end of the other side facing the front end of the push button is bent and replaced by the operation end of the trip crossbar. The method of claim 1, The push button is combined with a return spring to be inserted into the cylindrical guide formed on the cover of the main body case of the circuit breaker, and the protrusion formed on the button is fitted to the main surface of the cylindrical guide to turn on the push button or An earth leakage circuit breaker comprising a longitudinal slit for guiding in the off direction, and an engagement end extending from the lower end of the slit in the circumferential direction to engage and hold the push button at a push and twist lock position; . The method of claim 2, Between the video current transformer mounted on the main body case of the circuit breaker and the side wall of the main body case, the megger test switch is embedded in a concave space surrounded by a U-shaped main circuit conductor passing through the video current transformer; Engaging convex portions are provided in the unit case for supporting the switch main body and the actuator, and the engaging convex portions are fitted into the engaging grooves formed on the side walls of the main body case to hold and hold the megger test switch at a predetermined position. Earth leakage circuit breaker. The method of claim 4, wherein A top cover is provided on the upper surface of the cover of the main body case of the circuit breaker, and the operation window hole of the push button is opened on the top cover while aligning with the operation end of the push button attached to the cover. .

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