JP5856822B2 - Current limiting circuit breaker - Google Patents

Description

  The present invention relates to a circuit breaker having a current limiting function for suppressing a circuit current when an abnormal current such as a short circuit current flows in the circuit, and in particular, two types of contacts for current limiting and contacts for circuit breaking. The present invention relates to a current limiting circuit breaker provided with a contact.

  There exists a thing of the structure disclosed by patent document 1 as a current limiting circuit breaker provided with the contact (auxiliary contact) for current limiting, and the contact (main contact) for electric circuit interruption | blocking. In this Patent Document 1, one or two NFB (No-Fuse-Breaker) type high-speed mechanical switches are arranged in series on an electric circuit as auxiliary contacts, and at least one of them is paralleled with a diode, a snubber circuit, a current limiting impedance, and the like. When an abnormal current occurs in the electrical circuit due to an accident in the power system, etc., the auxiliary contact is opened to limit the current, and then the main contact high-voltage cutoff switch is opened to shut off. ing.

JP 2008-270171 A (FIG. 11)

  However, in Patent Document 1, the high-speed mechanical switch is constituted by a known circuit breaker (NFB). Therefore, when providing a current limiting breaker in a three-phase circuit, in addition to the three high voltage cutoff switches, Three circuit breakers were required for diversion. Thus, when applied to a three-phase circuit, at least six mechanical switches are required, so the entire current-limiting circuit breaker becomes large, and the main and auxiliary contacts are also used for interrupting and closing operations. It was necessary to throw in each, and the operation was troublesome. For this reason, there has been a demand for a small current limiting circuit breaker that can be turned on with a simple operation.

  Therefore, in view of such a problem, the present invention is provided with a main contact and an auxiliary contact made of a mechanical switch, and is capable of closing both the main contact and the auxiliary contact provided on the three-phase electric circuit with one operation handle. It aims to provide a flow breaker.

In order to solve the above-mentioned problems, the invention of claim 1 is directed to three main contacts for interrupting an electric circuit when an abnormal current exceeding the rated current flows in an electric circuit composed of three phases, and for each of the main contacts. At least one set of auxiliary contacts arranged in series, and at least one set of the auxiliary contacts is connected to a diode and a snubber circuit in parallel, and receives the occurrence of the abnormal current, An opening control means for opening the auxiliary contact independently is provided, and when an abnormal current flows in the electric circuit, the opening control means opens the auxiliary contact for current limiting operation, and then the main contact opens for interruption operation. A current-limiting circuit breaker having a main shaft that is arranged over a three-phase electric circuit to rotate the three main contacts, and the auxiliary contact is normally biased in a closing direction. And keep open And a latch release means for releasing the latch of the latch means in response to rotation of the main shaft in the closing direction, and the auxiliary contact in the open state is an operation handle for opening and closing the main contact In response to the rotation of the main shaft caused by the closing operation, the latch means is released and the auxiliary contact is closed.
According to this configuration, since the opened auxiliary contact is held in the open state by the latch means, the opened auxiliary contact is not closed until it is separately closed, and the current limiting operation is stably performed. To do. Since the auxiliary contact in the open state is closed by receiving the closing operation of the operation handle for opening / closing the main contact, it is not necessary to separately close the auxiliary contact. Further, since the latch means is released by the rotation of the main shaft for closing the main contact and the auxiliary contact is also closed, the auxiliary contact can be closed by a simple mechanism. Furthermore, the main contact and the auxiliary contact can be arranged around the main shaft, so that all the contacts can be easily accommodated in one housing, and the current limiting circuit breaker can be downsized.

According to a second aspect of the present invention, in the configuration of the first aspect, the opening control means includes an electromagnetic coil having a plunger for opening the auxiliary contact for each auxiliary contact, while the abnormal current generated in the electric circuit When an abnormal current is detected, an abnormal current detecting means for supplying a plunger drive current to the electromagnetic coil is provided. When the abnormal current flows in the electric circuit, the electromagnetic coil pulls in the plunger and opens the auxiliary contact. It is characterized by that.
According to this configuration, the auxiliary contact opens when an abnormal current flows in the electric circuit. And since it opens by the pulling-in operation | movement of the plunger provided in the electromagnetic coil, it can open at high speed and can carry out current-limiting operation quickly.

  According to the present invention, the auxiliary contact in the open state is closed by receiving the closing operation of the operation handle for opening / closing the main contact, so that it is not necessary to separately close the auxiliary contact. Further, since the latch means is released by the rotation of the main shaft for closing the main contact and the auxiliary contact is also closed, the auxiliary contact can be closed by a simple mechanism. Furthermore, the main contact and the auxiliary contact can be arranged around the main shaft, so that all the contacts can be easily accommodated in one housing, and the current limiting circuit breaker can be downsized.

It is an external view which shows an example of the current limiting circuit breaker which concerns on this invention. FIG. 2 is an explanatory diagram for explaining a contact state in an operation handle off state in FIG. 1, (a) is a front view, and (b) is a cross-sectional explanatory diagram showing a contact state. FIG. 2 is an explanatory diagram for explaining a contact state in an operation handle ON state in FIG. 1, (a) is a front view, and (b) is a cross-sectional explanatory diagram showing a contact state. It is explanatory drawing which shows the structure of a main contact part and an auxiliary contact part, (a) shows the normal OFF state which interrupted | blocked the electric circuit, (b) has shown the normal ON state which connected the electric circuit. FIG. 2 is a circuit diagram of FIG. 1. It is explanatory drawing of the contact part which shows the flow which carries out interruption | blocking operation | movement, (a) is the state at the time of interruption | blocking operation start, (b) is the state where one step of interruption | blocking operation was complete | finished, (c) is two steps of interruption | blocking operation completed Thus, the shut-off operation is completed. It is explanatory drawing of the contact part which shows the flow of operation at the time of re-inserting the current limiting circuit breaker which interrupted | blocked operation, (a) is the state immediately after releasing the latch of an auxiliary contact, (b) is the latch released. (C) shows a state where the second stage of re-charging is completed and the re-charging is completed. It is front view explanatory drawing of the connection state of an operation handle and a principal axis, and an off operation state. It is a front view explanatory drawing which shows the connection state of an operation handle and a main shaft, and is an ON operation state. It is a perspective explanatory view of a contact part in case another example of the present invention is shown and auxiliary contacts are provided in duplicate. It is a circuit diagram of the current limiting circuit breaker of the structure shown in FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 is an external view showing an example of a current limiting circuit breaker used in a three-phase electric circuit according to the present invention, and shows a configuration including a set of main contacts 11 and a set of auxiliary contacts 12 described later. In FIG. 1, reference numeral 1 denotes a power supply side terminal, 2 denotes a load side terminal, 3 denotes an operation handle for opening and closing, and the main contact and the auxiliary contact are all incorporated in the housing 5. Reference numeral 7 (7b) denotes a connection terminal for connecting a snubber circuit or the like.

  2 and 3 show the relationship between the operation handle 3, the main contact and the auxiliary contact, FIG. 2 (a) is a front view of the state in which the operation handle 3 is turned off, and FIG. 2 (b) shows the state of the contact at that time. FIG. FIG. 3A is a front view showing a state in which the operation handle 3 is turned on, and FIG. 3B shows a contact state at that time. 2 and 3, reference numeral 10 denotes a main shaft arranged so as to cross each of the three-phase electric circuits, 11 denotes a main contact that is arranged in each of the three-phase electric circuits to interrupt the electric circuit, and 12 denotes the main contact 11. Are auxiliary contacts for limiting the electric circuit current, 13 is a main contact electromagnetic coil for driving the main contact 11 via the main shaft 10, and 14 is an auxiliary contact electromagnetic coil for driving the auxiliary contact 12. is there. The main contact electromagnetic coil 13 and the auxiliary contact electromagnetic coil 14 are provided for each electric circuit so as to form a pair with the contact.

  Of the connection terminals 7 (7a, 7b, 7c), the central connection terminal 7c is not necessary when there is one auxiliary contact, and is provided when there are two auxiliary contacts 12 described later.

  FIG. 5 shows a circuit diagram of this current limiting circuit breaker. As shown in FIG. 5, the main contact 11 and the auxiliary contact 12 are provided in series in each circuit of the three-phase circuit L, and a connection terminal 7 (for connecting a current limiting means (not shown) such as a snubber circuit). 7a, 7b) are provided at both ends of the auxiliary contact.

4A and 4B are explanatory views in which a main contact mechanism that opens and closes the main contact 11 and an auxiliary contact mechanism that opens and closes the auxiliary contact 12 are extracted. FIG. 4A is a normal OFF state in which the electric circuit L is opened, and FIG. A normal on state with L connected is shown. The main contact 11 is a high withstand voltage cut-off switch, and includes a disconnect fixed contact 18a and a disconnect movable contact 19a.
The main contact mechanism includes a disconnecting fixed seat 18 provided with a disconnecting fixed contact 18a, a disconnecting movable contact 19a provided at the tip, a disconnecting blade 19 for opening and closing the disconnecting movable contact 19a by a rotating shaft 20 provided at a base, and a disconnecting A disconnect link 21 having a connection pin 21 a integrated with the blade 19 and connected to the main shaft 10 is provided, and a disconnect connection fitting 22 having a long hole 22 a into which the connection pin 21 a of the disconnect link 21 is fitted on the main shaft 10. Is provided.
The rotating shaft 20 and the main shaft 10 of the disconnecting blade 19 are fixed to the housing 5.

  The auxiliary contact 12 is a high-speed mechanical switch, and includes a fixed auxiliary contact 25a and a movable auxiliary contact 26a. The auxiliary contact mechanism presses the fixed seat 25 provided with the fixed auxiliary contact 25a, the blade 26 provided with the movable auxiliary contact 26a at one end, and the blade insulator 27 constituting the other end of the blade 26 to rotate the blade 26. Engaging piece 29 having a pusher 28a for driving the movement, an electromagnetic coil 14 having a plunger 28 to which the pusher 28a is fixed, and a hook-shaped tip for holding the rotating state (open state) of the blade 26. A latch pin 30 provided on the blade 26 so that the latch piece 29 engages, an engagement step portion 31 provided at the base of the latch piece 29 to release the latch of the latch piece 29 to the latch pin 30 and the like. I have.

The blade 26 is L-shaped around the blade rotation shaft 26b, and opens and closes the movable auxiliary contact 26a by rotating. Further, the engagement step portion 31 is engaged with the main shaft 10 so that the engaging piece 29 is rotated around the rotation shaft 29a. On the other hand, the main shaft 10 is provided with an engagement fitting 33 made of a rectangular protrusion that engages with the engagement step portion 31.
The electromagnetic coil 14, the blade rotation shaft 26 b, and the rotation shaft 29 a of the engagement piece 29 are fixed to the housing 5.

The transition from the OFF state in FIG. 4A to the ON state in FIG. 4B is performed as follows. First, in the normal state with the operation handle 3 off as shown in FIG. 2A, the contacts are in the state shown in FIG. At this time, the main contact 11 is in the opened off state, the auxiliary contact 12 is in the on state in contact, and since the main contact 11 is opened, the electric circuit L is interrupted and no current flows.
When the operation handle 3 is turned on from this state, the state shifts to the state shown in FIG. 4B, the main contact 11 comes into contact with the on state, and the auxiliary contact 12 remains on without changing. As a result, the electric circuit L becomes conductive.
Specifically, when the operation handle 3 is turned in the ON direction, the main shaft 10 is rotated, and the disconnecting blade 19 is rotated via the disconnecting coupling fitting 22 and the disconnecting link 21. As a result, the disconnect movable contact 19a contacts the disconnect fixed contact 18a. Further, during this operation, the engagement piece 29 is not engaged with the engagement pin 30, so that the engagement fitting 33 contacts the engagement step portion 31, but the contact state of the auxiliary contact 12 is not changed.

  Next, the breaking operation of the current limiting breaker configured as described above will be described. 6A and 6B are explanatory diagrams of the contact portion showing the flow of the breaking operation, where FIG. 6A is a state at the start of the breaking operation, FIG. 6B is a state where one stage of the breaking operation is completed, and FIG. The state where the stage is completed and the blocking operation is completed is shown. As shown in FIG. 6, when an abnormal current such as a short-circuit current flows through the electric circuit L, the opening operation is performed in two stages. That is, the auxiliary contact 12 is opened first, and the main contact 11 is opened after a delay. In addition, the state where the current limiting breaker is turned on before the interruption operation is the state shown in FIG.

Specifically, when an abnormal current is generated in the circuit L, an abnormal current detection means (not shown) provided separately from the current limiting circuit breaker detects this, and an abnormality occurs at a timing within a half cycle of the circuit current. An operating current is supplied to the auxiliary contact electromagnetic coil 14 provided in the electric circuit L where the current is generated. As a result, an electromagnetic force is generated in the electromagnetic coil 14 and the plunger 28 is instantaneously drawn at a timing of about a half cycle of the circuit current, and the pusher 28a moves in the direction indicated by the arrow P1 in FIG. push. By this operation, the auxiliary contact 12 in the state of FIG. 4B is changed to the state shown in FIG. 6A, and the movable auxiliary contact 26a that has been in contact with the fixed auxiliary contact 25a is turned off (dissociation operation).
By the turning-off operation of the auxiliary contact 12, an electric circuit current flows through a snubber circuit (not shown) connected in parallel to the auxiliary contact 12, and the electric circuit current is reduced (current limiting).

  The blade 26 is always urged in a direction in which the movable auxiliary contact 26a contacts the fixed auxiliary contact 25a by an urging means such as a torsion spring (not shown) provided on the blade rotation shaft 26b. When the opening operation proceeds, the engagement piece 29 is engaged with the engagement pin 30 of the blade 26 and the open state is maintained. As a result, it does not turn on until it is separately closed. This is the state of FIG. 6B, and the first stage of the blocking operation is completed. Note that the pushing tool 28a that protrudes returns to the original specified position due to a decrease in the electric circuit current.

On the other hand, the operating current is also supplied from the external abnormal current detecting means to the main contact electromagnetic coil 13 provided in the electric path L where the abnormal current is generated, and the main shaft 10 is moved as shown in FIG. Rotate in the direction of arrow Q1 (not detailed). As a result, the three main contacts 11, 11, 11 open simultaneously.
Specifically, the main shaft 10 rotates in the direction of the arrow Q1 shown in FIG. 6B by the action of the main contact electromagnetic coil 13. As a result, the disconnecting blade 19 rotates about the rotation shaft 20 in the direction indicated by the arrow R1 in FIG. 6B via the connected disconnecting link 21, and the disconnecting movable contact 19a opens.
The rotation of the main shaft 10 is held by a holding means (not shown) and does not return until a closing operation by the operation handle 3 is performed. As a result, the state shown in FIG. 6C is obtained, the second stage of the blocking operation is completed, and the blocking operation is completed. Thus, the three-phase electric circuit L is cut off by opening the main contact 11, and the electric circuit and the devices on the electric circuit are protected.

  In addition, a total of three auxiliary contacts 12, 12, and 12 provided in three phases operate independently by three electromagnetic coils 14, 14, and 14 provided in each electric circuit. Then, the operation handle 3 moves from the on position to a trip position (not shown) by the rotation of the main shaft 10.

The resetting and recharging operation of the current limiting circuit breaker thus interrupted is as follows. FIG. 7 is an explanatory view for explaining the flow of operation of the contact portion when the current-limiting circuit breaker that has been interrupted is operated again, (a) is a state immediately after the latch of the auxiliary contact is released, (b) Indicates a state where the latch is released and the first stage of the recharging operation is completed, and (c) indicates a state where the second stage of recharging is completed and the recharging is completed. This will be described with reference to this figure.
When the operating handle 3 that is in the tripping state in the shut-off state is rotated in the closing direction, the main shaft 10 rotates in the direction of the arrow Q2 in FIG. 7A opposite to the shut-off operation. Then, first, the engagement of the engagement piece 29 with the engagement pin 30 is released (the state shown in FIG. 7A). As a result, the blade 26 is biased by a torsion spring (not shown) and rotates in the direction of the arrow S1 shown in FIG. 7B, so that the movable auxiliary contact 26a contacts the fixed auxiliary contact 25a.

Thereafter, when the operation handle 3 is continuously rotated in the closing direction, the main shaft 10 is further rotated, and the disconnecting blade 19 is rotated in the direction indicated by the arrow R2 in FIG. The disconnect movable contact 19a contacts the fixed contact 18a (state shown in FIG. 7C). In other words, the main contact 11 is connected and the recharging operation is completed. In this way, the electric circuit L is connected.
If the operation handle 3 is turned off in this state, the main shaft 10 rotates and only the main contact 11 is dissociated. This is a reset state, which is the normal off state shown in FIG.

Here, a connection structure in which the main contact 11 is opened and closed by operating the operation handle 3 will be briefly described. 8 and 9 show the connection structure of the operation handle 3 and the main shaft 10, FIG. 8 is an explanatory view in front view of FIG. 8 in the off operation state as in FIG. 2, and FIG. . This will be described with reference to this figure. In addition, the upper part shown in figure is demonstrated as an upper part of a circuit breaker.
The shaft 3a of the operation handle 3 is connected to the first connecting member 40 and a second connecting member 41 having a rotating shaft (not shown) at the lower portion and connected to the first connecting member 40. It is composed of members and is connected to the upper end of a link member 42 that extends and bends. The lower end of the link member 42 is connected to the main shaft 10, and the rotation operation of the operation handle 3 is transmitted to the main shaft 10 via the first connecting member 40, the second connecting member 41, and the link member 42, and the main shaft 10 rotates.

A coil spring 44 is attached between the second connecting member 41 and the center bending center of the link member 42. The upper end of the coil spring 44 connected to the second connecting member 41 is moved to the left to the position shown in FIG.
In the state shown in FIG. 8, the link member 42 by the coil spring 44 is urged in the bending direction. However, when the axis X1 of the coil spring 44 moves to the left side from the position indicated by the axis X2 shown in FIG. It is energized in the direction of extension opposite to the above.
As a result, when the operation handle 3 is in the OFF state, the link member 42 is urged in the bending direction, so that the rotational force in the direction of the arrow T1 shown in FIG. 8 is applied to the main shaft 10, and the main contact 11 is in the open state. To maintain. On the other hand, when the operation handle 3 is turned on, the link member 42 is urged in the extending direction, so that a rotational force in the direction of the arrow T2 shown in FIG. 9 is applied to the main shaft 10, and the main contact 11 is closed. To maintain. Thus, the main contact 11 is opened and closed by operating the operation handle 3.

As described above, since the opened auxiliary contact 12 is maintained in the open state when the engaging piece 29 is engaged with the engaging pin 30, the opened auxiliary contact 12 is not closed until it is separately closed. The current limiting operation is performed stably. Then, the auxiliary contact 12 in the open state is closed by receiving the closing operation of the operation handle 3 for opening / closing the main contact 11, so that it is not necessary to separately operate the auxiliary contact 12. In addition, since the latch of the latch piece 29 is released by the rotation of the main shaft 10 that operates the main contact 11, and the auxiliary contact 12 is also closed, the auxiliary contact can be closed by a simple mechanism. Further, the main contact 11 and the auxiliary contact 12 can be arranged around the main shaft 10, and all the contacts can be easily accommodated in one housing 5, and the current limiting circuit breaker can be downsized.
Further, since the auxiliary contact 12 is opened by the movement of the plunger 28 of the electromagnetic coil 14, it can be opened at high speed, and the current limiting operation is performed quickly.

In the above embodiment, a case where a set of auxiliary contacts 12 is provided, that is, a case where one auxiliary contact 12 is provided for each electric circuit L, but a plurality of sets of auxiliary contacts 12 may be provided. By providing a plurality, the withstand voltage of the auxiliary contact 12 can be increased.
FIG. 10 shows a specific configuration when two sets of auxiliary contacts 12 (first auxiliary contact 12a and second auxiliary contact 12b) are provided. In FIG. 10, the first auxiliary contact 12a has the same configuration as the auxiliary contact 12 of the above embodiment, 125 is a fixed seat of the second set of auxiliary contacts 12b, 125a is a fixed auxiliary contact, 126 is a blade, 126a is movable It is an auxiliary contact. Reference numeral 114 denotes an auxiliary contact electromagnetic coil that presses the second set of blades 126. As shown in FIG. 10, when two sets of auxiliary contacts 12a and 12b are provided, they can be arranged in a space-saving manner by arranging them in a zigzag manner so as to face each other. FIG. 11 shows this circuit diagram, and a third terminal 7 c is provided as the connection terminal 7.

  3 ... Operation handle 7 ... Connection terminal 10 ... Spindle 11 ... Main contact 12 ... Auxiliary contact 14 ... Auxiliary contact electromagnetic coil (opening control means) 28 ... Plunger (opening control) Means), 28a .. pusher, 29 .. Engagement piece (latch means), 30 .. Engagement pin (latch means), 31 .. Engagement step (latch release means), 33.

Claims (2)

When an abnormal current exceeding the rated current flows in a three-phase electric circuit, at least one set of three main contacts for interrupting the electric circuit and auxiliary contacts arranged in series with respect to each of the main contacts The at least one set of auxiliary contacts each include a diode and a snubber circuit connected in parallel with each other, and provided with an opening control means for independently opening the auxiliary contacts of each electric circuit in response to the occurrence of the abnormal current, When an abnormal current flows in the electric circuit, the opening control means opens the auxiliary contact to perform a current limiting operation, and then the main contact opens and operates to interrupt the current limiting circuit breaker,
While having a main shaft that is arranged across a three-phase electric circuit and rotates to interlock the three main contacts,
The auxiliary contact is normally biased in the closing direction, and includes latch means for holding the open state, and latch release means for releasing the latch of the latch means in response to rotation of the main shaft in the closing direction. ,
The auxiliary contact in the open state receives the rotation of the main shaft due to the closing operation of the operation handle for opening and closing the main contact, the latch of the latch means is released, and the auxiliary contact is closed. Current limiting circuit breaker. The opening control means includes an electromagnetic coil having a plunger for opening the auxiliary contact for each auxiliary contact,
An abnormal current detection means for detecting an abnormal current generated in the electric circuit and supplying a plunger driving current to the electromagnetic coil when detecting the abnormal current,
2. The current limiting circuit breaker according to claim 1, wherein when an abnormal current flows through the electric circuit, the electromagnetic coil pulls in the plunger and opens the auxiliary contact.

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