JPH11213851A - Undervoltage tripping device for circuit-breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a nonconformities such as an accident by closing in non- voltage state by engaging the engaging part of a hook with a lock bar so that the mounting of a cover is incapable of being performed, in the mounting of the cover in the state where a movable core is attracted, after the removable of the cover. SOLUTION: A cover 18 is removed, and a movable core is pushed up with hands and attracted to a fixed core to perform a maintenance and inspection work. At this time, an operating lever continues the returning rotation against the working force of a third spring by the returning rotating force by the working force of a second spring, even after the contact edge of a hook 14 makes contact with a lock bar 12, and the hook 15 separates from the shaft and relatively rotates clockwise on the operating lever. The contact point between the hook 15 and the lock bar 12 is moved on the contact edge by this rotation, the contact point separates from the contact edge over the top part, relatively rotates counterclockwise through the action of the third spring, and fits in the inside of U-shape of the hook 15. Thus, the locking engaging part 15b of the hook 15 is engaged with the lock bar 12, so that the mounting of the cover 18 is becomes incapable of conducted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undervoltage trip device for a circuit breaker, and more particularly to a technique for preventing a malfunction of the undervoltage trip device using a permanent magnet when performing maintenance and inspection of the circuit breaker.

[0002]

2. Description of the Related Art There is an undervoltage relay as a device for protecting a circuit by generating a trip signal when a circuit voltage falls below a predetermined value. This undervoltage relay, particularly a circuit breaker equipped with an electronic undervoltage relay, often includes a magnetic flux switching type trip device that operates a trip mechanism of the circuit breaker in response to a trip signal.

[0003] This magnetic flux switching type trip device comprises a fixed core, a movable core, a coil surrounding the movable core, a permanent magnet for maintaining the fixed core and the movable core in an attracted state, and a movable core separated from the fixed core. And a spring acting in the direction of separation. Then, the circuit breaker can be closed when both cores are in the suction state, and the tripping mechanism of the circuit breaker operates when the movable core is separated from the fixed core, and the closed circuit breaker is opened. . In this magnetic flux switching type trip device, a voltage having a polarity that generates a magnetic flux in the opposite direction to the magnetic flux of the permanent magnet is applied to the coil from the capacitor of the electronic undervoltage relay when the circuit voltage falls below a predetermined value, The attraction between the movable core and the fixed core by the permanent magnet is reduced, and the movable core is separated by the action of the spring.

On the other hand, when the circuit breaker is removed from the electric circuit during maintenance or inspection, a voltageless state is established, and the magnetic flux switching type tripping device operates to open the circuit breaker.
When operating the opening / closing mechanism of the circuit breaker in such a state, the movable core may be manually moved against the action force of the spring to forcibly adsorb the fixed core. Even when the undervoltage relay is forcibly adsorbed in the non-voltage state, no voltage is supplied to the coil to open the undervoltage relay because power is not supplied to the undervoltage relay.

[0005]

An undervoltage trip device using such a magnetic flux switching type trip device includes:
If the circuit breaker after maintenance and inspection is returned to the electric circuit with the movable core sucked by hand, the circuit breaker can be closed even if the electric circuit is in no-voltage or low-voltage state. If such an operation is performed, there is a problem that a failure occurs in the electric circuit.

[0006]

In order to solve the above-mentioned problems, the present invention provides a frame-shaped yoke formed of a magnetic material, a fixed core and a movable core that are attracted to and separated from each other in the yoke. A permanent magnet that holds the attracted state between the fixed core and the movable core, a first spring that urges the movable core in a direction to separate the movable core from the fixed core, and a deficiency that operates when the voltage of the electric circuit falls below a predetermined value. A coil that generates a magnetic flux in the opposite direction to the magnetic flux of the permanent magnet due to the operation of the voltage relay,
In an undervoltage trip device for a circuit breaker including a cover that covers a yoke, a lock rod attached to a movable core, an operation lever that rotates following the movement of the cover in attaching and detaching the cover, and an operation lever. A second spring for urging the cover in a direction to remove the cover, a hook rotatably provided on the operation lever and having a contact side with the lock bar and a lock engaging portion, and engaging the hook with the lock bar at the lock engaging portion. A third spring that biases the movable lever in a direction in which the movable core is attracted while the cover is removed and the operating lever is rotated against the bias of the second spring, and then the operating lever is released. Then, the hook rotates together with the operation lever and comes into contact with the lock bar. After the contact, the corresponding contact moves on the contact side, and then the lock bar and the lock engagement portion are brought into a position where they can be engaged. Yo hook is characterized by rotating the upper operating lever.

With such a configuration, when the cover is once removed, the movable core is adsorbed to the fixed core, and then the cover is to be reattached, the lock engagement portion of the hook provided on the operation lever is engaged with the lock rod. Engagement prevents rotation of the operating lever.

Furthermore, when the movable core is attracted while the operating lever is rotated by hand to the same position as when the cover is attached, and the operating lever is released to reattach the cover, the operating lever is moved together with the hook together with the hook. It returns and rotates by the action of the two springs. By this return rotation, the contact side of the hook comes into contact with the lock bar, and the operation lever continues the return rotation, whereas the hook rotates on the operation lever against the action of the third spring. Due to this rotation, the contact moves on the contact side, and when the contact side is separated, the hook rotates and returns to a position where the lock engagement portion and the lock bar can be engaged by the action of the third spring. If the cover is to be mounted in this state, the lock engagement portion of the hook engages with the lock rod as described above, and the rotation of the operation lever is prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an undervoltage trip device for a circuit breaker according to the present invention will be described with reference to examples.

FIG. 1 is a front view of a circuit breaker 2 equipped with a magnetic flux switching type tripping device 1 used in this embodiment, FIG. 2 is a front sectional view of the magnetic flux switching type tripping device 1, and FIG.
7 are top views of the magnetic flux switching type trip device 1. FIG.

2 to 7, a magnetic flux switching type trip device 1 includes a frame surrounded by a yoke 3 and a yoke 4, both of which are formed by bending a magnetic material into a U-shape, and the inside of the frame. A movable core 5 of a magnetic material that can be moved up and down, a coil 7 wound around a coil bobbin 6 so as to surround the movable core 5, a magnetic material that is attached between the inside of the yoke 3 and the step of the coil bobbin 6. The spacer 8 and the fixed core 9, a permanent magnet 10 sandwiched between the spacer 8 and the fixed core 9, a lock rod 12 attached to the movable core 5 and extending upward, and a compression spring made of a compression spring for urging the movable core 5 downward. 1 spring 13, movable core stopper 11 for restricting downward movement of movable core 5, operation lever 14 rotatably provided on the upper outside of yoke 3, and operation lever 14 rotatably provided Erareru comprises a hook 15 and a second spring 16 and the third spring 17 are made of torsion applying a rotational force spring to the operating lever 14 and the hook 15.

FIG. 2 shows a reset state in which the movable core 5 is attracted to the fixed core 9 by the magnetic flux of the permanent magnet 10, and also shows a state in which a cover 18 shown in FIG. In this reset state, the circuit breaker can be freely closed or tripped.

Such a magnetic flux switching type trip device has a voltage applied to the coil 7 such that when the circuit voltage decreases, a magnetic flux in a direction opposite to the magnetic flux of the permanent magnet 10 is generated from an electronic undervoltage relay (not shown). Supplied. Due to this voltage supply, the attraction force between the movable core 5 and the fixed core 9 is weakened, and the movable core 5 is lowered by the biasing force of the first spring 13 to a position restricted by the movable core stopper 11. The bottom 5a operates a tripping mechanism (not shown) of the circuit breaker 2 so that the circuit breaker is tripped.

The magnetic flux switching type tripping device 1 in a trip state can be mechanically attracted to the fixed core 9 by pushing up the movable core 5 with a hand or the like, or can be permanently stopped when the circuit voltage exceeds a predetermined value. An electronic undervoltage relay is configured so that a voltage that generates magnetic flux in the same direction as the magnet is supplied to the coil 7, and the movable core 5 is automatically attracted to the fixed core 9 so as to be in a reset state. it can.

Next, a configuration for an interlock, which will be described later, of the magnetic flux switching type trip device 1 will be described.

In FIG. 1, a magnetic flux switching type tripping device 1 comprises:
Attached inside the cover 18 which can be removed by pulling it in and can be attached by pushing in,
FIGS. 3 and 7 are top views of the magnetic flux switching type trip device 1 showing a state where the cover 18 is attached and detached, respectively. In these figures, the operation lever 14 is rotatably held by fitting a hole formed in the opposite surface of the “U” -shaped bent portion into a shaft 19 attached to the yoke 3, and the hook 15 is It is rotatably held by a shaft 20 attached to a hole formed in the facing surface.

The operating lever 14 is urged in a counterclockwise direction by a second spring 16, and an operating arm 14a extending from the "U" -shaped bent portion is provided with a cover 18 in the state of FIG. In the state of FIG. 7 in which the yoke 4 is detached, the rotation of the yoke 4 is restricted by contact with the protrusion 4a. When the cover 18 is attached, the end 18a pushes the operation arm 14a to rotate the operation lever 14 clockwise. When the cover 18 is removed, the operation of the operation arm 14a follows the movement of the cover end 18a by the action of the second spring 16. And rotate counterclockwise.

On the other hand, the hook 15 is urged counterclockwise by the third spring 17, and its one arm 15a abuts on the shaft 19 to prevent its rotation.

Next, an interlock operation according to the embodiment of the undervoltage trip device will be described. The purpose of this interlock is to remove the circuit breaker 2 from the electric circuit, perform maintenance and inspection work involving opening and closing operations, and then return the circuit breaker 2 to the electric circuit without any trouble. When performing such an operation, it is necessary to remove the cover 18 and push up the movable core 5 which has been separated, by hand, to adsorb the movable core 5 to the fixed core 9. After the work is completed, the movable core 5 is separated from the fixed core 9. This is an interlock in which the cover 18 cannot be attached unless otherwise. Although not shown in detail, the cover 18 is formed so that the movable core cannot be mechanically operated after being attached.

First, in the actual use state of FIG. 3 with the cover attached, the hook 15 is not at a position where the operation of the lock bar 12 is obstructed, so that the movable core can be freely adsorbed and released, and the circuit breaker can be opened. Closing operation and trip operation are free.

In the maintenance inspection state shown in FIG. 7 with the cover completely removed, the lock rod 12 is
Is located in the middle of the substantially “U” -shaped opposing side, and the movable core can be freely adsorbed and separated, and the circuit breaker can be freely closed and tripped. Further, when the maintenance and inspection work is completed and the cover 18 is attached in a state where the movable core 5 is separated from the fixed core 9, the lock bar 12 is moving downward in FIG. From cover 1
When the operating lever 1 is pushed in, it is pushed by its end 18a.
The cover 4 rotates clockwise without engaging with the lock bar 12 together with the hook 15 so that the cover 18 can be attached.

Next, the first interlocking operation of this embodiment is as follows. When the cover 18 is to be mounted while the movable core 5 is attracted to the fixed core 9, the cover 18 is integrated with the operation lever 14 from the state shown in FIG. The hook 15 is slightly rotated clockwise, and the lock engaging portion 15b of the hook 15 contacts the lock rod 12 as shown in FIG. 6, and after the contact, the rotation of the hook 15 is prevented by the shaft 19. Because
The operation lever 14 has an interlock function that the operation lever 14 cannot be rotated any more and the cover 18 cannot be attached.

By the way, if it is only for the first interlock function, the operating lever 14 and the hook 15 do not need to be separate parts that can be disassembled from each other. May be. However, such a component form causes the following problem. That is, when the cover 18 is attached, the movable core 5 is attracted to the fixed core 9 while the operation arm 14a is rotated clockwise by hand (in FIG. 3, the operation arm 14a is held by hand instead of the cover 18). Then, when the operator releases the operating arm 14a, the operating lever 14 returns and rotates counterclockwise together with the hook 15, and the hook 15 is moved to the lock rod 1 as shown in FIG.
Contact 2 By this contact, when the operation lever 14 and the hook 15 are an integral part, the return rotation of the operation lever 14 is prevented but the clockwise rotation is free.
There is a problem that the cover 18 can be attached.

Therefore, the second interlock operation of this embodiment will be described. In the undervoltage trip device according to this embodiment, since the operation lever 14 and the hook 15 are formed as separate components as described above, no problem occurs even when the cover is mounted as described above. That is, in this embodiment, the contact side 15c of the hook 15 contacts the lock rod 12 as shown in FIG. Then, even after the contact, the operating lever 14 maintains the return rotational force due to the acting force of the second spring to the third rotational force.
The return rotation is continued against the acting force of the spring. By this rotation, the hook 15 is detached from the shaft 19 and relatively rotates clockwise on the operation lever 14. Due to this clockwise rotation, the contact point between the hook 15 and the lock bar 12 is brought into contact with the contact side 1.
5c, the contact point moves over the top and separates from the contact side 15c as shown in FIG. 5, rotates relatively counterclockwise by the action of the third spring 17, and the "U" -shaped hook 15 It enters inside and becomes the state of FIG. 6 from FIG. When the cover 18 is to be pushed in in the state of FIG. 7, the lock engagement portion 15b of the hook 15 is engaged with the lock rod 12 as described above, and the cover 18 cannot be attached.

As described above, the second interlock function is that the movable core 5 is sucked while pressing the operation lever 14, and the operation is performed as soon as the hand is released from the operation lever 14 to pick up the cover 18 which has been removed. Since the lever 14 returns to the original position, the cover 18 cannot be mounted.

[0026]

The present invention is embodied in the form described above. In order to open and close the circuit breaker without any voltage during maintenance and inspection work, the cover is opened and the movable core is forcibly sucked. Even if the user attempts to attach the cover after the operation with the hook engaged with the lock rod, the cover cannot rotate the operation lever, and thus cannot be attached. Since the circuit breaker does not return to the electric circuit in an incompletely assembled state where the cover is not attached, according to the present invention, the movable core does not return in a state in which the movable core is attracted to the fixed core, and the electric circuit in a voltageless state Thus, it is possible to prevent problems such as accidents caused by closing the circuit breaker.

[Brief description of the drawings]

FIG. 1 is a front view of a circuit breaker to which an embodiment of an undervoltage trip device according to the present invention is attached.

FIG. 2 is a front sectional view of the undervoltage trip device of FIG. 1;

FIG. 3 is a partial top view for explaining the operation of the undervoltage trip device in FIG. 1;

FIG. 4 is a partial top view for explaining the operation of the undervoltage trip device of FIG. 1;

FIG. 5 is a partial top view for explaining the operation of the undervoltage trip device of FIG. 1;

FIG. 6 is a partial top view illustrating the operation of the undervoltage trip device in FIG. 1;

FIG. 7 is a partial top view for explaining the operation of the undervoltage trip device of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnetic flux switching type trip device 2 circuit breaker 3 yoke 4 yoke 5 movable core 6 coil bobbin 7 coil 8 spacer 9 fixed core 10 permanent magnet 12 lock rod 13 first spring 14 operating lever 14a operating arm 15 hook 15 15a arm 15b lock Engaging portion 15c Contacting side 16 Second spring 17 Third spring 18 Cover 18a End 19 Shaft 20 Shaft

Claims (1)

[Claims] 1. A frame-shaped yoke formed of a magnetic material, a fixed core and a movable core that are attracted and separated from each other in the yoke, and a permanent magnet that holds the attracted state of the fixed core and the movable core. A first spring biasing the movable core in a direction to separate from the fixed core; and a magnetic flux of the permanent magnet due to an operation of an undervoltage relay that operates when a voltage of an electric circuit becomes equal to or less than a predetermined value. An undervoltage trip device for a circuit breaker comprising: a coil that emits a magnetic flux in a reverse direction; and a cover that covers the yoke. A lock rod that is mounted on the movable core; and the cover that is attached and detached by the cover. An operation lever that rotates following the movement of the cover; a second spring that urges the operation lever to rotate in a direction in which the cover is removed; A hook having a contact side with the lock bar and a lock engagement portion, and a third spring for urging the hook in a direction in which the lock engagement portion can engage with the lock bar. When the operating lever is released after the movable core is attracted while the cover is removed and the operating lever is rotated against the bias of the second spring,
The hook rotates together with the operation lever to contact the lock bar, and after the contact, the corresponding contact moves on the contact side, and then the lock bar and the lock engagement portion are brought into a position where they can be engaged. An undervoltage trip device for a circuit breaker, wherein the hook rotates on the operation lever.