JPH04355025A - Voltage tripping device for circuit breaker - Google Patents

Abstract

PURPOSE:To obtain large tripping force with a small electromagnet. CONSTITUTION:A point, where a trip lever 24 associated with a movable magnet 23 of a voltage tripping device 17 is brought into contact with an acting piece 18 of a trip cross bar 13, is set to a point P1 of large radius H1 of rotation, in the point of time of starting trip action, and transferred to a point P2 of small radius H2 of rotation at the moment a latch receiver 11 is dislocated from a pawl 14 of the trip cross bar 13. In this way, large tripping force is obtained in the beginning of trip action with small attractive force of the movable magnet 22, and a sufficient turning amount of the trip cross bar 13 can be generated in a stage of increasing the attractive force.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention operates a circuit breaker such as a hardwired circuit breaker by operating an electromagnet in response to an external command, which acts on a trip crossbar that locks a tripping mechanism, thereby shutting down the circuit breaker. This invention relates to a trip-operated voltage tripping device.

0002

2. Description of the Related Art FIG. 4 is a longitudinal sectional view showing a closed state of a conventional circuit breaker (mold circuit breaker) equipped with the above-mentioned voltage tripping device. In the figure, current flows from a fixed contact 1 integrated with a power supply terminal, through a movable contact 2, a lead wire 3, and a heater conductor 4a of an overcurrent tripping device 4 to a load terminal 5. The movable contact 2 is pressed against the fixed contact 1 by the action of an opening/closing spring 9 via a toggle link 8 that connects a holder 6 holding it and a latch 7 of the opening/closing mechanism. The latch 7 that receives the reaction force from the toggle link 8 is connected to the support shaft 1
0 is subjected to a counterclockwise torque in the figure, but the locking end 7a is locked by the latch receiver 11 and held in the reset state shown in the figure.

[0003]Also, the latch receiver 11 receives torque around the support shaft 12 in the clockwise direction in the figure due to the force from the latch 7, but the contact end 11a is applied to the claw 14 fixed to the trip crossbar 13. They are in contact and locked in the state shown. At this time, the force acting on the pawl 14 from the latch receiver 11 is set to pass through the center of the support shaft 15 of the trip crossbar 13, and the trip crossbar 13 maintains the state shown in the figure without receiving almost any torque. There is. The trip crossbar 13 is integrally provided with a trip arm 16 that receives the operating force from the overcurrent tripping device 4, and an actuating piece 18 that receives the operating force from the voltage tripping device 17, which is the object of the present invention. There is.

When an overcurrent flows through such a circuit breaker, the overcurrent tripping device 4 is activated, and the bimetal 4b or armature 4c pushes the trip arm 16 to the left in the figure, causing the trip crossbar 13 to move counterclockwise. direction. As a result, the latch receiver 11 is disengaged from the pawl 14 and rotated clockwise to release the latch 7. As a result, the latch 7 rotates counterclockwise, and in the process, the action of the opening/closing spring 9 is reversed, the toggle link 8 collapses, and the movable contact 2 is rapidly pulled up clockwise to interrupt the current. .

As described above, the overcurrent trip device 4 detects an overcurrent and trips the circuit breaker, but the voltage trip device 17 trips the circuit breaker by command from a distance. By similarly rotating the trip crossbar 13 via the operating piece 18, the movable contactor 2 is opened. Voltage trip device 1
Reference numeral 7 is attached to the main body case of the circuit breaker so as to be located on the side of the opening/closing mechanism, and this will be explained below based on FIGS. 5 to 9. Here, FIG. 5 is a plan view of the voltage tripping device 17, FIG. 6 is a side view thereof, FIG. 7 is an enlarged view of the main part of FIG. 6 showing the state at the time of starting the tripping operation, and FIG. FIG. 3 is an enlarged view of the main part showing an intermediate state.

First, in FIGS. 5 and 6, 19 is a base made of molded resin, 20 is a yoke held by press-fitting into this, and inside the yoke 20 is a cylindrical fixed magnet 21, which is opposed to this. Movable magnet 22,
and an electromagnetic coil 23 surrounding them. In front of the movable magnet 22, the yoke 20 has a two-armed trip lever 24 rotatably supported by a support shaft 25, one arm 24a of which is connected to the movable magnet 22, and the other arm 24b of which is connected to the trip lever 24. It is designed to cover and engage with the actuating piece 18 of the cross bar 13. The trip lever 24 is biased counterclockwise in FIG. 6 by a return spring 26, which is a torsion spring attached to a support shaft 25, and is held at the position shown.

Here, when a voltage is applied to the electromagnetic coil 23 as a trip command from the outside, the movable magnet 22
is attracted by the fixed magnet 21, and accordingly, the trip lever 24 is rotated clockwise against the return spring 26. The rotated trip lever 24 hits the actuating piece 18 that engages with the arm 24b, causing the trip crossbar 13 to rotate counterclockwise. As a result, as described above, the abutting end 11a of the latch receiver 11 comes off the claw 14 of the trip crossbar 13, and the circuit breaker is shut off.

A microswitch 27 de-energizes the electromagnetic coil 23 when the tripping operation of the circuit breaker is completed to prevent its burnout, and is operated by an actuator 28 that detects the tripping position of the tripping mechanism. Electromagnetic coil 23
When the excitation is released, the movable magnet 22 and the trip lever 24 are returned to the illustrated state by the action of the return spring 26.

FIG. 7 shows the state before the arm 24b of the trip lever 24 comes into contact with the actuating piece 18, and in this state, the contact end 11a of the latch receiver 11 moves against the trip crossbar 13 with a coefficient of k. It is in contact with the claw 14 of. Further, FIG. 8 shows the state at the moment when the trip lever 24 rotates the trip crossbar 13 and the abutting end 11a of the latch receiver 11 comes off from the claw 14. At that point, the arm 24b of the trip lever 24 is applying a force to a point P0 of the operating piece 18 whose rotation radius from the center of the support shaft 15 is H0. This point P0 remains substantially stationary during the tripping operation, and therefore the radius of rotation H0 is also substantially constant.

FIG. 9 shows the attraction stroke of the movable magnet 22 during the tripping operation by the voltage tripping device 17, the force (trip load) that the movable magnet 22 receives from the trip lever 24, and the attraction force generated by the electromagnetic coil 23. FIG. In the figure, the trip load acting on the movable magnet 22, which starts attracting from the point of stroke S0, gradually increases as the return spring 26 deforms, and the trip load acting on the movable magnet 22, which starts attracting from the point of stroke S0, gradually increases as the return spring 26 deforms.
rapidly increasing in terms of This rapid increase is mainly due to the frictional force between the latch receiver 11 and the pawl 14. This trip load is applied to the return spring 26 and the trip crossbar 13.
It gradually increases as the deformation load of the back spring (not shown) increases, and suddenly decreases at the stroke S2 when the latch receiver 11 comes off the claw 14. After that, the return spring 26
The deformation load gradually increases until the movable magnet 22 is attracted to the fixed magnet 21 and ends. On the other hand, as for the attraction force, the attraction of the movable magnet 22 progresses, and the attraction of the fixed magnet 2 increases.
The closer it gets to 1, the larger it becomes.

[0011]

[Problems to be Solved by the Invention] By the way, in order to attract the movable magnet 22 to perform the tripping operation, it is necessary to apply a necessary and sufficient tripping force (driving torque) and rotation amount to the trip crossbar 13. Suction power and stroke are required. In that case, the rotation radius H0 of the actuating piece 18
If you increase , you can get a greater tripping force with the same suction force, but on the other hand, the required stroke also increases. Conventionally, therefore, the size of H0 is determined by considering the balance between the necessary suction force and stroke.

On the other hand, in recent years, circuit breakers have become smaller and smaller.
Since the space for installing the voltage tripping device 17 is also narrow, it is difficult to increase the size of the electromagnet and give the movable magnet 22 sufficient suction power. As a result, as shown in FIG. 9, due to variations in component accuracy, there may be cases where the trip load exceeds the suction force and the trip becomes impossible, and a large number of man-hours are spent on adjustment. In that case, the trip load cannot be easily reduced because it is related to the basic characteristics of the circuit breaker. Therefore, a voltage tripping device that is small but has sufficient tripping force is desired. The present invention is in response to such demands, and aims to provide a voltage tripping device for a circuit breaker that has sufficient tripping force without increasing the size of the electromagnet.

[0013]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that the contact point between the trip lever and the actuating piece shifts from a point where the radius of rotation of the actuating piece is large to a point where the radius of rotation of the actuating piece is small in the process of tripping operation. It is configured to do so. In this case, it is more advantageous to downsize the electromagnet if the moment when the rotation radius of the actuating piece changes from a large point to a small point is the moment when the tripping mechanism is unlocked by the trip crossbar.

[0014]

[Operation] In this invention, at the beginning of the tripping operation, the trip lever contacts a point with a large rotation radius of the actuating piece;
The contact point between the trip lever and the actuating piece is divided into two stages so that the movable magnet comes into contact with a point with a small rotation radius when the attraction of the movable magnet has progressed to a certain extent. That is, at the time of starting the tripping operation when the suction force is small, the trip lever is brought into contact with a point of the operating piece having a large rotation radius to generate a large tripping force. However, as it is, sufficient rotation amount cannot be given to the trip crossbar 13, so when the movable magnet's attraction has progressed to a certain extent, the contact point is moved to a point with a small rotation radius of the actuating piece to obtain a large rotation amount. do. As the radius of rotation becomes smaller, a larger suction force is required, but at this stage there is no problem because the movable magnet approaches the fixed magnet and the suction force becomes large.

In that case, the point at which the contact point between the trip lever and the actuating piece moves to a point with a small rotation radius of the actuating piece is the moment when the tripping mechanism is unlocked by the trip crossbar (the moment when the latch receiver moves away from the pawl). If the moment of release), the trip crossbar can be driven with a large rotation radius during locking where the trip load is large, and the electromagnet can be made more compact.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be described based on FIGS. 1 to 3. Here, FIG. 1 is a side view of the main part of the voltage tripping device showing the state at the start of the tripping operation, FIG. 2 is a side view of the main part showing the state in the middle of the tripping action, and FIG. 3 is an operating characteristic diagram. Note that the same reference numerals are used for parts corresponding to those in the conventional example, and descriptions of the same parts are omitted. 1 and 2, the operating piece 18 of the trip crossbar 13 has an inclined surface 29 formed on the side that engages with the arm 24a of the trip lever 24, and when the tripping operation is started, as shown by the chain line in FIG. The arm 24b comes into contact with a point P1 at the upper end corner of the inclined surface 29 of the actuating piece 18, and pushes the actuating piece 18 through that point until a certain period of time. Then, as the tripping operation progresses, at the moment when the contact end 11a of the latch receiver 11 comes off the claw 14 of the trip crossbar 13 (at the moment when the coefficient k=0), the actuating piece 18a is tilted as shown in FIG. It comes into contact with point P2 at the lower end corner of the surface 29, and thereafter continues to reach the end of the stroke of the movable magnet 22.

Here, the support shaft 1 of the trip crossbar 13
The radius of rotation H1 from the center of 5 to point P1 is larger than the radius of rotation H0 of the conventional example, and the radius of rotation H2 from the center of point P2 to point P2 is smaller than the radius of rotation H0. Therefore, if the tripping force required for the trip crossbar 13 is the same, the trip load acting on the movable magnet 22 will be smaller than in the conventional case, and the surplus power for the attraction force will increase. However, if the rotation radius of the actuating piece 18 remains large, the stroke of the movable magnet 22 will be insufficient for the required amount of rotation of the trip crossbar 13. Therefore, at the moment when the tripping mechanism is unlocked by the trip crossbar 13, that is, at the moment when the latch receiver 11 disengages from the pawl 14, the contact point is moved to a point P2 with a small rotation radius and a large rotation is made with a smaller stroke than in the past. I'm trying to get some movement.

FIG. 3 is an operational characteristic diagram showing the above-mentioned relationship based on the same suction force and stroke as in the conventional example. In the figure, the trip load acting on the movable magnet 22 whose suction has started at the stroke S0 increases rapidly at the stroke S1 when the arm 24b of the trip lever 24 hits the P1 point of the actuating piece 18. The trip load is smaller than the conventional example and does not exceed the suction force. The trip load then gradually increases, rapidly decreases at the stroke S4 when the latch receiver 11 comes off the pawl 14, and then gradually increases again until reaching the end.

In the above embodiment, the point at which the contact point moves to point P2 is the point at which the latch receiver 11 comes off from the claw 14, so that the trip load is lower than that in the conventional example throughout the stroke S1 to S4, where a large trip load is applied. This makes it possible to downsize the electromagnet accordingly. Also, after the stroke point S4, the contact point is moved to the P2 point and the trip crossbar 1 is used for the remaining stroke.
However, since the trip load in this case is only the spring load, the rotation ratio of the trip cross bar 13 to the stroke of the movable magnet 22 can be set sufficiently large, and the movable magnet 22 It is possible to reduce the length of the electromagnet in the front-rear direction by reducing the amount of stroke required. Note that the point of stroke S3 (
3), and in that case, the trip load increases at the moment the contact point shifts, as shown by the broken line in the figure. However, at that point, the suction power has also increased, so there is no problem.

[0020]

According to the present invention, the movable magnet Since the trip load can be lowered at the beginning of the trip operation when the suction force is low, there is no risk of trip failure due to insufficient suction force, and when the suction force increases, the rotation ratio of the trip crossbar to the stroke of the movable magnet increases. Therefore, the required amount of rotation of the trip crossbar can be secured with a small stroke. In particular, it is effective to downsize the electromagnet if the point of contact is set to be the moment when the tripping mechanism is unlocked by the trip crossbar.

[Brief explanation of drawings]

FIG. 1 is a side view of a main part of a voltage tripping device according to an embodiment of the present invention, showing a state at the time of starting a tripping operation.

2 is a side view of a main part showing a state in the middle of a tripping operation of the voltage tripping device of FIG. 1; FIG.

FIG. 3 is an operational characteristic diagram of the voltage tripping device of FIG. 1;

FIG. 4 is a longitudinal cross-sectional view of a circuit breaker equipped with a conventional voltage tripping device.

FIG. 5 is a plan view of the voltage trip device in FIG. 4;

FIG. 6 is a side view of FIG. 5;

FIG. 7 is a side view of a main part of the conventional example shown in FIG. 6, showing a state at the start of a tripping operation.

8 is a side view of a main part showing a state in the middle of a trip operation in the conventional example of FIG. 6; FIG.

FIG. 9 is an operation characteristic diagram of the conventional example shown in FIG. 6;

[Explanation of symbols]

11 Latch receiver 13 Trip crossbar 14 Nails 17 Voltage trip device 18 Actuation piece 22 Movable magnet 24 Trip lever H1 Turning radius H2 Turning radius P1 Contact point P2 Contact point

Claims (2)

[Claims] Claim 1: Voltage tripping of a circuit breaker in which a movable magnet is attracted by an external command to drive a trip lever, and the operating piece of a trip crossbar that engages with the trip lever is struck to trip the circuit breaker. A voltage tripping device for a circuit breaker, characterized in that the contact point between the trip lever and the actuating piece shifts from a point with a large rotation radius of the actuating piece to a point with a small rotation radius during the tripping process. . 2. The moment when the contact point between the trip lever and the actuating piece shifts from a point with a large rotation radius of the actuating piece to a point with a small rotation radius is defined as the moment when the lock of the tripping mechanism by the trip crossbar is released. A voltage tripping device for a circuit breaker according to claim 1.