KR20020090870A - Electromagnetic tripping device for circuit breaker - Google Patents

Abstract

PURPOSE: To carry out a stable trip operation by matching a load weight on an armature as a reactive force and the attraction characteristic of an electromagnet to effectively use the small and small-capacity electromagnet when driving a trip crossbar by the attracting operation of the electromagnet. CONSTITUTION: This electromagnetic trip device is used for tripping a circuit breaker by detecting an overcurrent in the main circuit and is so structured that an operation arm 14a formed on the armature 14 of an electromagnet unit 7 is faces a trip arm 8a of the trip crossbar 8, the operation arm presses the trip arm of the trip crossbar in the attracting operation of the electromagnet, and thus the breaker is tripped by releasing a latch receiver 9. By changing the force application point between the operation arm and the trip arm from a point P1 to a point P2 in line with the change of an air gap (g) between the armature and the electromagnet in the attracting operation of the electromagnet, the load weight applied to the armature is kept low in the first half causing small attraction, and the force application point is moved to the point P2 in the second half increasing the attraction of the electromagnet so that the trip crossbar is driven to a release position.

Description

Electronic tripping device for circuit breaker

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic trip device for a circuit breaker for an automatic breaker, an earth leakage breaker, or the like.

(Conventional technology)

First, the structure of the circuit breaker which becomes the target of implementation of this invention is shown in FIG. 3 using the above-mentioned autobreaker as an example. In the drawings, reference numeral 1 denotes a circuit breaker case, 2 a power supply side terminal, 3 a fixed contactor, and 4 a movable contactor. 5 is a contact opening and closing mechanism, 6 is an opening and closing operation handle, 7 is an electromagnet unit of an overcurrent trip device, 8 is a trip crossbar associated with the electromagnet unit 7, 9 is a contact between the contact opening and closing mechanism 4 and the trip crossbar 8; 10 is a load side terminal, and an electromagnetic coil of the electromagnet unit 7 is mounted between the load side terminal 10 and the movable contact 4 and connected to the main circuit.

In addition, the electromagnet unit 7 is an oil dashpot-type coil in which an electromagnet coil 11 and a pole 12a are inserted into the electromagnet coil 11 downward as shown in FIG. 4. The iron core 12, the L-shaped yoke 13 and the branch armature 14 and the rear end of the armature 14 hinged freely hinged to the lower end of the yoke 13 were bent in an L shape to the yoke 13 And an operation arm (14a) extending behind, each part is assembled to the unit case (15), and then embedded in the breaker case (1) of FIG.

The operation of such a circuit breaker is well known, and in the illustrated ON state, the main circuit current flows from the power supply side terminal 2 to the fixed contact 3, the movable contact 4, and the electromagnet coil 11 of the electromagnet unit 7. ) And flows to the load side via the load side terminal 10. Here, when the operation handle 6 is inclined to the off position, the opening and closing mechanism 5 drives the movable contact 4 to the off position. In addition, when an overcurrent flows in the main circuit, the armature 14 is attracted to the pole 12a by the suction operation of the electromagnet unit 7, and the operation arm 14a provided in the armature 14 swings. The trip arm 8a of the trip crossbar 8 shown in FIG. 3 is struck to release the engagement of the trip crossbar 8 and the latch receiver 9. For this reason, the contactor opening / closing mechanism 4 trips and the movable contactor 4 is opened and separated, and the main circuit current is interrupted | blocked.

Next, the linkage | movement operation | movement of the armature 14 and the trip crossbar 8 at the time of the suction operation | movement of the said electromagnet unit 7 is demonstrated in FIG. 5 (a)-(d). First, Fig. 5 (a) shows a steady state in which the circuit breaker is turned off or the rated current is energized in the main circuit, and the armature 14 of the electromagnet unit 7 is contacted by the spring force of the return spring 16. It retracts from the pole 12a to the position which isolate | separated (pore length g). Moreover, in this steady state, it opposes the operation arm 14a extended upward from the rear end of the armature 14, and the trip arm 8a protruded downward from the trip crossbar 8, and also latches. The engaging piece 9a of the base 9 touches the nail part 8b of the trip crossbar 8, and is supported at this position. In addition, the trip crossbar 8 is spring-loaded to the standby position shown by the return spring (not shown), and the latch 9 is spring-loaded counterclockwise with the upper end as a swinging point.

On the other hand, when an overcurrent flows through the electromagnet coil 11 of the electromagnet unit 7, as shown in FIGS. 5 (b) and 5 (c), the armature 14 is attracted toward the pole 12a by the attraction force of the electromagnet. In response to this movement, the operation arm 14a swings counterclockwise from the hinge point O, and the tip of the arm strikes the trip arm 8a of the trip crossbar 8, thereby causing the trip crossbar 8 to be moved. Press clockwise. Also. The contact point (acting point of a force) which the front-end | tip of the operation arm 14a and the trip arm 8a abut is shown as P. FIG. Then, as shown in FIG. 5 (d) through the state of FIG. 5 (c), when the armature 14 is brought into the state of being adsorbed by the pole 12 a, the engaging piece 9 a of the latch 9 is coupled with the engaging piece 9 a. The engagement with the nail portion 8b of the trip crossbar 8 is separated, and the latch receiver 9 swings counterclockwise by a biasing spring to release the latch of the contact opening and closing mechanism (see FIG. 3). As a result, the opening and closing mechanism trips, causing the movable contact 4 to open and cut off the main circuit current.

However, if the circuit breaker is miniaturized and power consumption is reduced, and then a small and small capacity electromagnet is employed for the electromagnet unit occupying a large space, the above-described conventional electronic trip device can be tripped as follows. The problem arises that the operation becomes unstable.

That is, in the characteristic diagram of FIG. 2 based on experimental data performed by the inventors, A is a suction force characteristic when 200% of an overcurrent flows through an electromagnet 330AT having a large rated capacity, and B is a small electromagnet having a rated capacity ( The attraction force characteristic at the time of passing 200% of electric current through 200AT) is shown. In addition, the suction force of the electromagnet is inversely proportional to the square of the pore length g (see Fig. 5 (a)) between the armature and the contactor.

On the other hand, in the electromagnetic trip device of FIG. 5, when the trip crossbar 8 is driven from the standby position to the release position by the suction operation of the electromagnet unit 7, a spring-loaded latch 9 and a trip crossbar are provided. Load load acting as a moment on the armature 14 via the operating arm 14a which abuts the trip arm 8a and the tip (touch point P) of the arm from (8) (in contrast to the magnetic attraction force of the electromagnet). The force that separates the armature from the pole) becomes the characteristic shown in C. In this example, the armature return spring 16 (see FIG. 5) is applied as the load load 5g.

Here, when the electromagnet having a large rated capacity is employed as the electromagnet unit 7, the suction force (characteristic A) is larger than the load load (characteristic C) of the armature, so that the trip crossbar 8 can be driven to the release position without any problem. have. In contrast, when an electromagnet having a small rated capacity is used to promote the miniaturization of the circuit breaker as described above, the portion C1 in which the suction force characteristic B and the load load characteristic C of the armature are shown in diagonal lines in the drawing (Fig. 5 (b) ), And the load load of the armature exceeds the suction force of the electromagnet in this portion. For this reason, the armature of the electromagnet stops at this position, and the trip arm of the trip crossbar can no longer be pushed in, and the circuit breaker cannot be tripped.

As described above, it is difficult to miniaturize the circuit breaker by employing a small and small capacity electromagnet as the electromagnet unit of the conventional structure.

The present invention has been made in view of the above point, and an object thereof is to match the attraction force characteristics of the electromagnet by distributing a load (work) acting as a reaction force to the armature of the electromagnet when the trip crossbar is driven by the suction operation of the electromagnet unit. It is an object of the present invention to provide an electronic tripping device for a circuit breaker which is improved in order to achieve a satisfactory combination and to effectively utilize a suction force of an electromagnet having a small rated capacity and to perform a stable trip operation.

(Means to solve the task)

In order to achieve the above object, according to the present invention, an electronic trip of a circuit breaker which detects and operates an overcurrent of a main circuit and trips an opening / closing mechanism of a main circuit contact through a trip crossbar and a latch receiver. A device, which replaces an operation arm provided in a rocker-type armature of an electromagnet unit that detects an overcurrent and aspirates and replaces a trip arm provided in a trip crossbar, and receives the suction force during operation of the electromagnet unit. The operating arm swinging together with the pressing arm of the trip crossbar, releases the latch and in which the opening and closing mechanism is tripped.

In accordance with the change of the gap length between the armature and the contactor during the suction operation of the electromagnet unit, the contact point between the operation arm and the trip arm is adjusted in the longitudinal direction of the operation lever. In the first half of the suction operation where the air gap is large, the contact point is set on the root side of the operating arm to suppress the load applied to the armature, and in the second half of the suction operation where the air gap is shortened. It is assumed that the contact point is moved to the tip side of the operation arm so as to drive the trip arm of the trip crossbar (claim 1),

As a specific aspect, the operation arm provided on the armature of the electromagnet unit and the trip arm provided on the trip crossbar are arranged so as to extend from each other and face each other, and the operation arm is a straight arm. According to this, a stepped portion that changes in a step shape on the opposite surface to the operation arm is formed (claim 2).

According to the above configuration, when the trip crossbar is driven to the release position by the suction operation of the electromagnet unit, in the first half (the gap length between the amateur and the pole is large and the magnetic attraction force is small), the trip arm of the trip crossbar and Since the working point with the operation arm is located at the base side of the operation arm, the moment load applied to the armature of the electromagnet from the trip crossbar side is suppressed to a low value by the principle of the lever principle. Therefore, even if the electromagnet has a small capacity with a relatively small suction force, the armature does not stop on the way, but can press the trip arm of the trip crossbar toward the release position via the operation arm.

On the other hand, when the armature's suction operation progresses and the void length is reduced, the inclination angle of the operation arms arranged in the armature is changed so that the contact point contacting the trip arm moves to the tip side of the operation arm. For this reason, the moment load applied to the armature from the trip crossbar side increases, but since the suction force of an electromagnet increases also when the armature gap length becomes small, a trip crossbar can be driven to a final position without a problem.

In other words, the contact point of the operation arm and the trip arm is changed stepwise along the longitudinal direction of the operation lever in accordance with the change in the gap length between the armature and the contactor during the suction operation of the electromagnet unit. The load of the armature corresponding to the work (force x distance) required to drive the crossbar from the standby position to the release position can be matched to the attraction force characteristics of the electromagnet, thereby effectively utilizing the attraction force of the electromagnet having a small and predetermined capacity. The circuit breaker can trip.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory view of a structure and a trip operation of an electronic trip device according to an embodiment of the present invention, in which (a) to (d) show different states of the trip operation.

Fig. 2 is a characteristic diagram showing the relationship between the pore length of an electromagnet and the load load of an armature in the electromagnetic trip device and the conventional electronic trip device of Fig. 1 together with the suction force of the electromagnet.

3 is a cross-sectional view of a circuit breaker that is the object of the present invention.

Fig. 4 is an exploded perspective view showing the assembling structure of the electromagnet unit in Fig. 3.

Fig. 5 is an explanatory view of the structure and trip operation of the electronic trip device employed in the conventional circuit breaker, in which (a) to (d) show different states of the trip operation.

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

3: fixed contact 4: movable contact

5: contactor opening and closing mechanism 7: electromagnet unit of electronic trip device

8: trip crossbar 8a: trip arm

8a-1: stepped portion 9: latch receiving

11: electromagnet coil 12a: pole

13: York 14: Amateur

14a: operating arm g: void length

P1, P2: landing point

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on the Example shown to FIG. 1, FIG. 1, the same code | symbol is attached | subjected to FIG. 5, and the description is abbreviate | omitted.

The electronic trip device of the embodiment shown in FIG. 1 is basically the same as the structure shown in FIG. 5, but extends downward from the trip crossbar 8 to be replaced by the side of the operation arm 14a of the electromagnet unit 7. The trip arm 8a is changed to the shape described next. 1 (a) to (d) show an operating state corresponding to Figs. 5 (a) to (d), respectively.

That is, in the trip arm 8a of the illustrated embodiment, the operation arm 14a, whose arm tip stands up from the bottom, is set to a length facing the center portion of the length of walking (see Fig. 5). In the conventional structure, the stepped portion 8a- which changes in a step shape along the longitudinal direction on the opposing surface of the trip arm 8a and the tip of the operating arm 14a faces each other). 1) is formed.

The trip operation by such a configuration is performed as follows. First, Fig. 1 (a) shows a steady state. As shown in Fig. 5 (a), the armature 14 of the electromagnet unit 7 is withdrawn from the pole 12a, and the operation arm 14a is directed to the right. It is stopped at the position separated from the trip arm 8a of the trip crossbar 8 in an inclined posture. Here, when the overcurrent flows to the main circuit and the electromagnet unit 7 starts a suction operation, the operation arm 14a swings counterclockwise with the hinge engaging portion of the armature 14 as the point O. In the position of FIG. 1B, the middle part (abdomen) of the operation arm 14a is pressed against the tip of the trip arm 8a. In this state, the contact point between the operation arm 14a and the trip arm 8a becomes P1, and the moment load acting on the armature 14 through the operation arm 14a from the trip crossbar 8 side is the contact force. The force (reaction force) applied to the point P1 is the product of the distance from the point O of the operation arm 14a to the landing point P1.

On the other hand, when the suction operation of the electromagnet proceeds further and the armature 14 is attracted to the position of Fig. 1 (c), and the inclination angle of the operation arm 14a changes, the contact point of the operation arm 14a and the trip arm 8a. It moves to the said step part 8a-1, and the contact point between the operation arm 14a and the trip arm 8a is moved from P1 to P2 by this. In this state, the moment load acting on the armature 14 through the operation arm 14a from the trip crossbar 8 side is the force applied from the force applied to the landing point P2 and the point O of the armature 14. It becomes a product of the distance to the point P2, and load load increases compared with the state of FIG. When the armature 14 is attracted to the pole 12a as shown in Fig. 1 (d), the engagement piece 9a of the latch 9 and the trip crossbar 8 are held as in the case of Fig. 5 (d). The engagement with the nail portion 8b is separated, and the latch receiver 9 swings counterclockwise by a biasing spring to release the latch of the contact opening and closing mechanism, which causes the opening and closing mechanism to trip to block the main circuit current. .

Here, if the load load of the armature 14 by the trip operation mentioned above is planned and shown on the characteristic diagram of FIG. 2, it will become like characteristic line D. FIG. In addition, the points D1 and D2 shown above the characteristic line D correspond to the states of Figs. 1 (b) and (c), respectively. As can be seen from this, the load load of the armature corresponding to the gap length g between the armature poles is changed into a step shape as shown, and the first half of the suction operation having a large gap length g is shown. At (wearing point P1), the load load increases when the armature load is small and the latter half of the suction operation (falling point P2) where the void length g is reduced (loading point P2), and the electromagnet under this stepped load pattern The trip crossbar 8 is driven to a release position by the suction operation of the unit 7. In addition, in the first half of the suction operation, by lowering the load load of the armature, even when an electromagnet having a small rated capacity is adopted, the suction force characteristic (B line) and the load load characteristic (D line) do not cross midway. In the second half of the suction operation, the load load increases, but the suction force of the electromagnet also increases, so that the trip crossbar can be driven to the final position without problems.

The present invention is not limited to the structure of the illustrated embodiment. In the illustrated embodiment, the step-shaped stepped portions for setting the contact points P1 and P2 are formed in the trip arm 8a. It may be formed on the 14a) side. Moreover, you may divide and set the contact point to three or more points according to the curve of the attraction force characteristic of an electromagnet.

As described above, according to the present invention, the operation arm provided in the branch armature of the electromagnet unit which detects an overcurrent and operates by suction is replaced with the trip arm of the trip crossbar, and the operation arm is a trip crossbar during suction operation of the electromagnet unit. In pressing trip arm of trip and opening and closing mechanism to trip operation,

According to the change of the gap length between the armature and the contactor at the time of the suction operation of the electromagnet unit, the contact point between the operation arm and the trip arm is changed stepwise along the length direction of the operation lever. In the first half of the large suction operation, the contact point is set at the base of the operation arm to suppress the load on the armature, and the second point of the suction operation with the smaller pore length is moved to the tip side of the operation arm to reduce the trip crossbar. By driving the trip arm,

When the circuit breaker trips, the pattern of load load acting on the armature of the electromagnet through the trip arm and the operation arm from the trip crossbar side is carefully matched with the suction force characteristics of the electromagnet unit. Even when an electromagnet having a rated capacity is employed, the circuit breaker can be tripped reliably by utilizing the suction force effectively, which makes it possible to reduce the size, the capacity of the electronic trip device mounted on the circuit breaker, and furthermore, the size and energy of the circuit breaker. It can contribute to the promotion of savings.

Claims (2)

An electromagnetic trip device of a circuit breaker which detects and operates an overcurrent of a main circuit and trips an opening / closing mechanism of a main circuit contact through a trip crossbar and a latch receiver. The operation arm provided at the rocker-type armature of the electromagnet unit and the trip arm provided at the trip crossbar are replaced, and the operation arm oscillated with the armature while receiving the suction force during the operation of the electromagnet unit. In the electronic trip device of a circuit breaker which presses a trip arm, releases a latch, and trips an opening / closing mechanism, In accordance with the change of the gap length between the armature and the contactor during the suction operation of the electromagnet unit, the contact point between the operation arm and the trip arm is adjusted in the longitudinal direction of the operation lever. In the first half of the suction operation where the air gap is large, the contact point is set on the root side of the operating arm to suppress the load applied to the armature, and in the second half of the suction operation where the air gap is shortened. An electronic trip device of a circuit breaker characterized by moving the contact point to the tip side of the operation arm to drive the trip arm of the trip crossbar. The method of claim 1, The operation arm provided on the armature of the electromagnet unit and the trip arm provided on the trip crossbar are arranged so as to extend from each other and face each other, and the operation arm is a straight arm, and the trip arm has the operation arm along the length direction thereof. An electronic trip device for a circuit breaker, characterized in that a stepped portion is formed in a step shape on an opposite surface of the circuit breaker.