JP2988027B2 - Earth leakage trip device for earth leakage breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet, a fixed magnetic pole and a movable iron core forming a series magnetic path of lines of magnetic force emitted from the permanent magnet, and a secondary current of a zero-phase current transformer through which a main circuit conductor passes. And a trip coil for transmitting the movement of the movable core. The trip spring is attached to a base having an opening on the side opposite to the fixed magnetic pole of the movable core, and trips the opening and closing mechanism. The present invention relates to an earth leakage trip device for an earth leakage breaker that waits for a secondary output of a zero-phase current transformer while holding a power storage state.

[0002]

2. Description of the Related Art FIG. 4 shows an example of the configuration of a conventional earth leakage trip device of this kind. The earth leakage tripping device exemplified here is fixed to a synthetic resin base, not shown here, but after inserting this base into the groove of the case of the circuit breaker body, it is immovably moved by the case of the circuit breaker body. It is fixed and located near the blocking part. The apparatus receives a rod-shaped permanent magnet 1 having a square cross section, a fixed magnetic pole 3 attached to a U-shaped yoke 2, a columnar movable core 4, and a secondary current of a zero-phase current transformer (not shown). It is provided with a trip coil 5 and is fixed to a base 9 made of a synthetic resin with a set screw 14.
A push rod 4 a is implanted in the movable iron core 4, and the tip end of the push rod 4 a normally holds the tripping spring 8 via an armature 7 in an energized state.

A ground current flows through the primary conductor of the zero-phase current transformer,
When the secondary current is rectified in a predetermined direction and flows through the trip coil 5, the fixed magnetic pole 3 cannot hold the movable iron core 4 in the attracted state, and is formed as a torsion spring wound around a shaft pin 10 fixed to the base 9. The armature 7 rotates counterclockwise about the shaft pin 10 by the force of the tripping spring 8 to trip the opening / closing mechanism (not shown), and the movable iron core 4 is driven in the direction of the arrow. You. The movement of the movable core 4 at this time is guided by a cylindrical guide 6.
An opening 9a for transmitting the movement of the movable core 4 to the opposite side of the base is formed in the base 9, and the movable core 4 moved as shown by the arrow pushes the display latch 11. The display latch 11 rotates around the shaft pin 13 toward the near side of the drawing sheet against the torsion spring 12, whereby the engagement between the engagement portion 11a with the display piece 15 and the engagement 15a with the display piece 15 is released. . The disengaged display piece 15 pops out to the left by the force of the spring 16, and indicates the breaking operation of the earth leakage breaker.

[0004]

As described above, an earth leakage breaker having a configuration in which a permanent magnet is used to hold the tripping spring in an energized state receives a spring force like a normal earth leakage breaker. An opening for transmitting the movement of the movable iron core to the base to which the earth leakage trip device is attached, although it has the advantage that the earth leakage trip device is smaller than the structure where the engagement of the open / close mechanism is tripped by an electromagnet. Is provided, the metal pieces and metal powder that enter from the outside to the inside of the earth leakage breaker, especially the metal pieces and metal powder scattered from the contact and its vicinity at the time of short-circuit interruption, are attracted to the permanent magnet through this opening, Attachment to the fixed magnetic pole and the attracting surface of the movable iron core causes a problem that the attracting force is insufficient when the armature returns after the current is interrupted, and the tripping spring cannot be held in the charged state. In particular, in the earth leakage breaker, usually, the contact of the interruption part is located on the side of the base opposite to the earth leakage trip device, and the metal powder from the contact goes straight and passes through the opening of the base. The potential for problems is great.

SUMMARY OF THE INVENTION An object of the present invention is to provide an earth leakage trip device having the configuration described at the outset, in which the entry of metal pieces or metal powder into the respective attracting surfaces of the fixed magnetic pole and the movable iron core is practically sufficiently prevented. is there.

[0006]

In order to solve the above-mentioned problems, according to the present invention, a permanent magnet, a fixed magnetic pole and a movable iron core forming a series magnetic path of lines of magnetic force coming out of the permanent magnet, and a main circuit conductor are provided. A trip coil through which a secondary current of a zero-phase current transformer that passes therethrough is input. The trip coil is attached to a base having an opening on the side opposite to the fixed magnetic pole of the movable core to transmit the movement of the movable core. The tripping spring for releasing the engagement of the mechanism is held in a charged state, and the leakage tripping device of the leakage breaker which waits for the secondary output of the zero-phase current transformer has elasticity and flexibility. It is assumed that the opening of the base is closed by a dust-proof cover having a peripheral wall rising from the inside of the ring-shaped flange made of rubber material and forming the peripheral edge to one side of the flange surface.

[0007]

As described above, the opening of the base is closed by the dust-proof cover having the peripheral wall rising from the inside of the ring-shaped flange forming the peripheral portion to one side of the flange surface, which is made of a rubber material having elasticity and flexibility. Then, the gap side between the movable core and the guide, which has the largest entry cross-sectional area among the entry paths to the fixed magnetic poles of the metal pieces and metal powder and the movable core adsorption surface, is closed, and the push rod and the armature side are closed. Although the entry through the gap with the fixed magnetic pole remains, the entry of metal pieces and metal powder is practically sufficiently prevented for the earth leakage trip device to maintain its function.

In addition, since the dustproof cover has a peripheral wall that rises from the inside of the ring-shaped flange forming the peripheral edge to one side of the flange surface, this peripheral wall is inserted inside the opening, and the ring-shaped flange is attached to the set screw. By simply holding the gap in the gap between the earth leakage tripping device fixed to the base and the surface of the base where the opening is formed, lateral displacement of the dust-proof cover is prevented, and the peripheral edge of the rubber plate is usually flat. The dust-proof function is maintained by maintaining the initial position without the need for a ring-shaped holding plate or the like, which is required when fixing the camera to the camera.

[0009]

FIG. 1, FIG. 2 and FIG. 3 show an embodiment of the present invention. In these drawings, the same members as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. As shown in FIG. 3, the dust-proof cover is formed from a ring-shaped flange 20a forming a peripheral portion through a fold 20b formed to avoid damage at the time of deformation to a peripheral wall 20c which rises to one side of the surface of the flange 20a.
The peripheral wall 20c is formed as a rubber molded product in which peaks and valleys are alternately and concentrically formed toward the center with the side surfaces of the peaks.

[0010] When the opening 9a is closed by the dustproof cover 20, the installation of the leakage prevention device to the base 9 is performed by first inserting the center of the dustproof cover 20 into the base 9, and then installing the leakage prevention device. This is performed by fixing the earth leakage trip device to the base 9 with the set screw 14 so that the dustproof cover flange 20a is sandwiched between the yoke 2 and the base 9. The dustproof cover 20 does not come off the base 9 even if a slight gap occurs between the yoke 2 and the base 9 due to a slight gap.

FIG. 1 shows a state in which the earth leakage trip device is on standby for earth leakage. In this state, the movable core 4 is not in contact with the dust cover 20. FIG. 2 shows a state in which a leakage has occurred in the main circuit and the leakage trip device has been operated by the secondary current of the zero-phase current transformer. At this time, the movable core 4 deforms the dustproof cover 20 as shown in the figure, but since the cross section of the dustproof cover 20 is wavy, the movable core 4 easily deforms without a large load on the movable core 4, As with the case without the cover, the engagement of the opening / closing mechanism and the engagement of the display piece and the display latch can be released.

In the structure of the present embodiment, the life test of the earth leakage breaker was performed as many times as required.
Of the portion between the movable iron core 4 and the projection of the display latch 11, the residual deformation was small, and there was no crack on the cover surface.

[0013]

As described above, according to the present invention, a permanent magnet, a fixed magnetic pole and a movable iron core forming a series magnetic path of lines of magnetic force coming out of the permanent magnet, and a zero-phase transformer through which the main circuit conductor passes. And a trip coil to which the secondary current of the current flowr is input. The trip coil is mounted on a base having an opening on the side opposite to the fixed magnetic pole of the movable iron core for transmitting the movement of the movable iron core. The earth leakage trip device of the earth leakage breaker, which holds the trip spring in the charged state and waits for the secondary output of the zero-phase current transformer, is made of a rubber material having elasticity and flexibility. Since the opening of the base was closed with a dustproof cover having a peripheral wall that rises from the inside of the ring-shaped flange forming the part to one side of the flange surface,
Fixed magnetic poles of metal pieces and metal powder attracted to permanent magnets,
On the side having the largest approach cross-sectional area to the movable core attraction surface, the earth leakage trip device is shielded from the source of the metal pieces and metal powder, and the movable core is securely attracted to the fixed magnetic pole surface. Thereby, the operation reliability of the earth leakage trip device is improved, and the reliability of the earth leakage breaker is improved. In addition, the dustproof cover can be easily attached, and the above-described effects can be obtained with a slight increase in the cost of the earth leakage breaker.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention around an earth leakage trip device in a standby state of the earth leakage trip device.

FIG. 2 is a side view of the vicinity of the earth leakage trip device, showing an embodiment of the present invention in an operation state of the earth leakage trip device.

3 (a) is a plan view, and FIG. 3 (b) is a cross-sectional view taken along the line AA of FIG. 3 (a).

FIG. 4 is a diagram showing a configuration example around a conventional earth leakage trip device, wherein FIG. 4 (a) is a plan view and FIG.

[Explanation of symbols]

 Reference Signs List 1 permanent magnet 3 fixed magnetic pole 4 movable iron core 5 trip coil 8 trip spring 9 base 9a opening 20 dust cover 20a flange 20c peripheral wall

Claims (2)

(57) [Claims] 1. A trip coil to which a secondary current of a zero-phase current transformer through which a main circuit conductor penetrates is input to a permanent magnet, a fixed magnetic pole and a movable iron core forming a series magnetic path of lines of magnetic force coming out of the permanent magnet. Attached to the base with an opening on the side opposite to the fixed magnetic pole of the movable iron core to transmit the movement of the movable iron core, the tripping spring that releases the engagement of the opening and closing mechanism is held in the charged state In the earth leakage trip device of the earth leakage breaker which waits for the secondary output of the zero-phase current transformer, the opening of the base is formed of a rubber material having elasticity and flexibility to form a ring-shaped peripheral portion. An earth leakage trip device for an earth leakage breaker, which is closed by a dustproof cover having a peripheral wall rising from the inside of the flange to one side of the flange surface. 2. The earth leakage trip device according to claim 1, wherein the dustproof cover having a peripheral wall that rises from the inside of the ring-shaped flange to one side of the flange surface includes a rubber plate,
An earth leakage trip device characterized by having a corrugated cross section formed by forming concavities and valleys alternately and concentrically inside a ring-shaped flange.