JPS59198629A - Circuit breaker - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a circuit breaker that is used for low voltage circuit protection and is capable of current-limiting cutoff and selective cutoff.

[Technical background of the invention]

Conventionally, circuit breakers as shown in FIGS. 1(a) to 1(d) have been used to protect low voltage circuits.

FIG. 1(a) shows a closed circuit state, and the current path of this circuit breaker consists of a breaker main body (hereinafter referred to as the breaker) 1 and a current limiter (hereinafter referred to as the current limiter) 2. The current-limiting part fixed conductor 3 and the current-limiting part movable arm 4 of the recessed part 2 form a parallel conductor, effectively exerting the electromagnetic repulsion force accompanying the passage of a large current. It is structured as follows. In such a circuit breaker, when a large current flows due to a short circuit accident, etc., the parallel conductors consisting of the fixed conductor 3 of the current limiting section 2 and the movable arm 4 of the current limiting section have opposite to each other. An electromagnetic repulsive force is generated by the short-circuit current flowing in the direction, and the current-limiting part fixed contact 5 and the current-limiting part movable contact 6
The current limiter contacts 5 and 6 (hereinafter referred to as current limiter contacts 5 and 6) are opened as shown in FIG. 1(b). At this time, an arc is generated between the current limiting contacts 5 and 6, and the short circuit current begins to be limited by this arc resistance. Furthermore, at the same time, the first
Due to the short-circuit current flowing through the breaker fixed conductor 7, the overcurrent line disconnection device 8, which has an instantaneous tripping current-operation time characteristic as shown in characteristic A shown in FIG. Start. In this case, since there is a slight mechanical time delay in the tripping mechanism (not shown), the breaker fixed contact 9 of the breaker 1 and the breaker movable contact 10 (hereinafter referred to as the breaker (abbreviated as 9 and 10) are temporarily maintained in a closed state. However, soon after Figure 1 (
As shown in c), the breaker contacts 9 and 10 of the breaker 1 are opened. At this time, the circuit breaker completes breaking and the current disappears, so the electromagnetic feedback in the current limiter 2 disappears, and the current limiter contact 5.6, which was open, is shown in Figure 1(d). The spring 11 causes the circuit to return to its original state and close the circuit again.

In the figure, 12 is an insulating case, 13 is a load side output terminal,
Reference numeral 14 represents a power supply side outlet terminal; 15 represents a supporting conductor that is provided upside down on the first breaker fixed conductor 7 to support the current limiter movable arm 4; and 16 represents the center of rotation of the current limiter movable arm 4. 17 is a second breaker fixed conductor with a load side output terminal 13 provided at its end; 18 is a breaker movable arm with a breaker movable contact 10 provided at its end; 19 is a first breaker fixed conductor; A removable conductor 20 electrically connects the breaker fixed conductor 7 and the breaker movable arm 18, and a handle for manual on/off operation of the breaker 1.

[Problems with background technology]

By the way, in such a circuit breaker, current-limiting breaker is performed by arc resistance, which has the advantage of increasing breaker capacity and reducing thermal and electromagnetic impact on the circuit, but short-circuit current The method quickly opens the contacts to limit the current before it becomes large, so
The circuit must be cut off instantly. Therefore, in a low voltage circuit in which two circuit breakers are installed, one on the upper side and the other on the lower side, characteristic B is shown in FIG.

If a short circuit occurs on the lower circuit breaker side, that is, on the load side, the characteristic A in FIG.

As shown in FIG. 2, the circuit breaker on the upper side having the characteristic A and the characteristic B intersect with each other, so both circuit breakers start the breaking operation at the same time. That is, since the upper breaker is also cut off, the range of power outage is expanded, and so-called selective cutoff is not possible.

As described above, when the current limiting section 2 performs current-limiting cutting, the cutting capacity is increased, but selective cutting is not performed.
Generally, it has been difficult to satisfy these requirements at the same time.

[Purpose of the invention]

The present invention was made based on the above circumstances, and an object of the present invention is to provide a circuit breaker capable of current-limiting cutoff and selective cutoff.

[Summary of the Invention] In order to achieve the above object, the circuit breaker according to the present invention is characterized by being configured as follows. That is, a breaker body having a short-time overcurrent exception device;
A current limiting section is connected in series with a current limiting section, which is equipped with a parallel conductor that generates an electromagnetic repulsion force when a large current flows, and the contacts are opened and opened by the electromagnetic repulsion force, and The present invention is characterized in that an electromagnet is attached to a conductor that forms a current-carrying path, and when the electromagnet is excited, it facilitates the opening/closing operation of the contacts.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Third
Figures (a) to (i) show an embodiment of the circuit breaker according to the present invention, and Figures 3 (a) (b) (c) (
d) is a block diagram, Figure 3 (e) (f) (g) (h)
(1) is an electrical equivalent circuit diagram. In addition, Figure 3 (a
) (,) indicates a closed circuit state.

In FIG. 3(a), 51 is an insulating case, and inside this, a breaker main body part (hereinafter referred to as a breaker part) 52
A current limiting section (hereinafter referred to as current limiting section) 53 is configured. Further, a load side outlet terminal 54 is led out from the breaker section 52 side of the insulating case 51, and a power source side outlet terminal 55 is led out from the current limiting section 53. In the current limiting section 53, a first current limiting section fixed conductor 56 having a power supply side output terminal 55 formed at one end thereof has a current limiting section fixed contact 57 provided at an intermediate portion, and a current limiting section fixed conductor 56 at the other end. One end of a resistor 58 is connected to the resistor 58. Further, an intermediate portion of a current limiter movable arm 60 is rotatably attached to a rotating shaft 61 at an intermediate portion of a support conductor 59 that is provided upside down on the insulating case 51 . Here, the rotation axis 6 is the current limiter movable arm 6.
00 rotation center.

On the other hand, a breaker fixed conductor, which will be described later, is supported and connected to one end of the support conductor 59, and further, one end of a second current limiter fixed conductor 62 is connected to the other end of the support conductor 59.

A current limiter movable contact 65 is provided at one end of the current limiter movable arm 60, and a movable iron core 64 is attached to the other end on the opposite side of the rotating shaft 61 by a pin 75. Also, the first
A fixed core 66 is provided in the current limiting portion fixed conductor 56 in correspondence with the movable core 64, and the movable core 64 and the fixed core 66 are connected to each other.
A spring 63 is attached between the two. This movable iron core 64
The fixed iron core 66 constitutes one electromagnet section, and is magnetized by the current flowing through the first current-limiting section fixed conductor 56. Details of this electromagnet section are shown in FIG. In FIG. 4, the fixed iron core 66 has a substantially U-shape, in which the first current-limiting portion fixed conductor 56 is energized and a spring 63 insulated by an insulating plate 78 is mounted. Said spring 6
3 acts to rotate the current limiter movable arm 60 clockwise about the rotation axis 61, and the current limiter contact 57.6
It generates the contact pressure when the circuit 5 is closed, and at the same time also serves as a return spring function for the electromagnet part. Further, the other end of the resistor 58 is connected to the other end of the second current limiting portion fixed conductor 62.

Further, the zero-order breaker section 52 will be described, in which the insulating case 51 facing the current limiter contacts 57 and 65 in the current limiter 53 is provided with an exhaust hole 77 for discharging gas at the time of breaker. In the breaker part 52, the load side outlet terminal 5
An overcurrent tripping device 68 is connected to one end of 4 via a conductor 67. This overcurrent train removal device 68 is
In addition to the instantaneous decoupling characteristic, it has a short time decoupling characteristic such as characteristic A2 shown in FIG. 5 so that when a short circuit current flows, the device operates with a cycle time delay. Further, one end of a flexible conductor 69 is connected to the other end of the overcurrent string disconnection device 68, and further, the other end of this flexible conductor 69 is connected to a movable breaker arm 70 that is rotatably provided. There is. The breaker movable contact 7 is located at the end opposite to the center of rotation of the breaker movable arm 70.
1 is provided. Further, the breaker fixed conductor 72 attached and connected to the base side of the support conductor 59 is provided with a breaker fixed contact 73 corresponding to the breaker movable contact 71 . In addition, 74 in the figure is a knob for operation.

Further, the insulating case 51 of the cutoff section 52 is provided with an exhaust hole 76 for releasing gas during cutoff.

Next, with reference to FIGS. 3(a) and 3(e), the energizing path of this circuit breaker will be described. In FIGS. 3(a) and 3(e), from the power supply side outlet terminal 55, through the first current limiter fixed conductor 56, the current limiter surface contact 57 and the current limiter movable contact 6.
5 (hereinafter, these are referred to as current limiter contacts 57 and 65), the current limiter movable arm 6θ, the rotation shaft 61, and the supporting conductor 59 to the breaking portion fixed conductor 72. Further, from the breaker fixed conductor 72, the breaker fixed contact 73 and the breaker movable contact 71 (hereinafter referred to as the breaker contacts 71 and 73) are connected to the movable contact arm 7o, the removable conductor 69, and the overcurrent string disconnector 68. , passes through the conductor 67 and reaches the load side terminal 54.

Next, the operation of the circuit breaker configured as described above will be explained. Now, a short circuit accident has occurred on the load side, and the 6th
Assuming that the short circuit current i1 shown in the figure flows, at the initial stage, the breaker contact 7
1.73 and current limiter contact 57.65 are in a closed state,
The current-carrying path is still formed. Next, Fig. 3(b) (f
), the first current-limiting part fixed conductor 56 and the current-limiting part movable arm 60 form parallel conductors, and since current flows in opposite directions, an electromagnetic repulsion force is generated between these parallel conductors. As a result, the current limiter contacts 57 and 65 begin to open and open. At the same time, the electromagnet section composed of the fixed iron core 66 and the movable iron core 64 is energized by the current flowing through the first current-limiting part fixed conductor 56, so the movable iron core 64 overcomes the repulsive force of the spring 63 and begins to be attracted. . In this case, both the electromagnetic repulsive force and the attractive force caused by the electromagnet move the current-limiting part movable arm 60 to the rotation axis 6.
1 and υ, and these two forces are combined, and the current limiter movable arm 60 rapidly rotates counterclockwise around the rotation axis 61. , the current limiter contacts 57 and 65f are rapidly opened. In addition, the rotation shaft 61 is connected to the current limiter movable arm 6 so that the limit sickle rotation moment is minimized.
Since the circuit breaker is installed at approximately the center of gravity at 0, its opening speed is significantly faster than that of the circuit breaker shown in FIG.

As described above, the current limiter contacts 57, 65 are rapidly opened and at the same time, the movable iron core 64 is strongly attracted to the fixed iron core 66 by the short circuit 11 flow and is held therein. In other words, the current limiter contacts 57,65 are held in the open position. Therefore, during this opening process, an arc occurs between the current limiting contacts 57 and 65, and the arc voltage rises more rapidly. (from i
The flow begins to be limited to 2. In addition, due to the arc resistance due to the arc generated between the current limiter contacts 57 and 65, the short circuit current is commutated to the resistor 58 forming a parallel circuit 'f:M with respect to the current limiter contacts 57 and 67. Start.

Next, the current limiter contacts 57 and 65 are completely opened, and the resistor 58
When the commutation to is completely completed, the arc between the current limiter contacts 57 and 65 disappears, as shown in FIGS. 3(b) and 3(g). Even after that, the short circuit current is limited by the resistor 58, and the limited current continues to flow, and while this current continues to flow, the movable iron core 64 continues to be attracted to the fixed iron core 66. This current is then applied to resistor 58.

If the current i3 is limited as shown in FIG. 6, the time required to complete this commutation is time t. Incidentally, the arc generated between the current limiter contacts 57 and 65 has an effect such as melting the metal parts in the vicinity, but
, the fixed iron core 66 and the spring 63 are provided on the opposite side of the current-limiting part contacts 57 and 65 with the support conductor 59 interposed therebetween, so that they are not damaged by arcing.

In addition, the arc gas generated during this cutoff process is discharged through the exhaust hole 7.
7 into the atmosphere.

Thereafter, the breaker contacts 71 and 73 are operated by the overcurrent train disconnection device 68 having a short-time trip characteristic such as characteristic A2 shown in FIG. 5, after a certain time delay, as shown in FIG.
As shown in (h), an arc is generated and the circuit opens, and the short circuit current begins to decrease further. Therefore, the suction force of the fixed iron core 66 of the current limiter 53 also begins to decrease, and further, due to the effect of the spring 63, the current limiter contacts 57, 65 shift to a closing operation.

When the breaker contact vx, 73 completes the breaker and the current becomes zero, the fixed core 66 is de-energized and the third
zl (d) As shown in (j), the current limiter contact 57.
65 is closed, and the breaker contacts 71 and 73 have completed opening (
~, the shutoff is completely completed.

During the shutoff process of the shutoff section 52, the generated arc gas is discharged into the atmosphere through the exhaust hole 76f.

Next, current limiting selective breaker using this circuit breaker will be explained with reference to FIG. 7. In FIG. In a low voltage circuit in which a lower circuit breaker α is connected to a lower general-purpose circuit breaker β having characteristic B2 in FIG. 5, that is, an instantaneous trip characteristic, the load side of the lower circuit breaker β Suppose that a short circuit accident occurs. In this case, the state in which the circuit breakers α and β are closed as shown in FIG. 7(a) first changes to the state shown in FIG. 7(b). In other words, the circuit breaker β on the lower side instantaneously opens its contacts and starts breaking due to the instantaneous tripping operation, and at the same time, the current limiting contacts 57 and 65 of the circuit breaker α on the upper side also instantaneously open due to electromagnetic repulsion. opens and begins to limit the short-circuit current. At this time, the arc energy is shared between the current limiting section of the lower breaker β and the upper breaker α, and the lower breaker β interrupts the current limited by the upper breaker α. Therefore, the breaker duty of the lower-order breaker β is significantly reduced. Next, when the lower side breaker β completes disconnection and the current becomes zero before the short time trip device 68 of the upper side breaker α operates, the current limiter contact 57.65 is reset again as already explained. The circuit is closed, resulting in a state as shown in FIG. 7(c). Therefore, power can be continuously supplied to healthy branch circuits.

In addition, if a short-circuit accident occurs between the upper circuit breaker α and the lower circuit breaker β, an overcurrent disconnector with short-time tripping characteristics is used as already explained in Fig. 3. The device 68 opens the breaker contacts 71.73 to interrupt the circuit.

As described above, in this embodiment, both current-limiting cutoff and selective cutoff are possible at the same time, so it is possible to provide an economical circuit protection system and at the same time, it is possible to limit the accident range to a minimum. becomes. The current limiter movable arm 60f opens due to electromagnetic repulsion, and at the same time as a short circuit occurs, the electromagnet excited by the short circuit current facilitates the opening operation, and at the same time, after opening, it is reliably held in that position. resistance 5
The commutation to 8 is well done. In addition, the current limiter contact 57
．． Since the electromagnet part km is formed in the current limiting part movable arm 60 so that the rotational moment during the opening operation of the contact opening 65 is minimized, the electromagnet part combines with the strong contact opening promoting action of the electromagnet part to minimize the rotational moment during the opening operation of the contact opening. A contact opening operation can be obtained, the arc voltage 1 voltage rises extremely quickly, and an excellent current limiting effect can be obtained. Furthermore, since the spring 63 that applies contact pressure to the current limiting contacts 57 and 65 is provided on the opposite side to the position where the arc occurs, the spring 63 will not be damaged by the arc at the time of interruption. In addition, since all the arc gas is released into the atmosphere at the time of shutoff, there is no chance of short-circuiting between phases within the insulating case 51.

〔Effect of the invention〕

As described above, according to the present invention, the breaker main body has a short-time overcurrent train disconnection device, and a parallel conductor that generates an electromagnetic repulsion force when a large current flows. The contacts are opened by electromagnetic repulsion, and an electromagnet is attached to a conductor that forms a normal current-carrying path in the current limiting section, and when the electromagnet is excited, the contacts are opened. Since the circuit breaker is configured so as to facilitate current-limiting and selective breaking, it is possible to provide a circuit breaker with extremely improved current-limiting performance by promoting the opening operation of the contacts.

[Brief explanation of drawings]

Figures 1 (a) to (d) are block diagrams showing a conventional circuit breaker, Figure 2 is a characteristic diagram showing the characteristics of current versus operating time in a conventional circuit breaker, and Figures 3 (a) to ( 1) (shows an actual example of the circuit breaker according to the present invention, FIGS. 3(a) to (d) are block diagrams, and FIGS. 3(e) to (i)
) is a turbulent equivalent circuit diagram, Fig. 4 is a partial detail diagram of Fig. 3, Fig. 5 is a characteristic diagram showing the characteristics of current vs. operating time that enables selective cutoff, and Fig. 6 is a diagram of the turbulent equivalent circuit. Waveform diagrams for explaining aspects of current limiting current in the figure, Figures 7(a) to (
c) is a circuit diagram for explaining current limiting cutoff and selective cutoff. 51... Insulation case, 52... Breaking part (breaker main body part), 53... Current limiting part (current limiting part), 54...
... Load side outlet terminal, 55... Power supply side outlet terminal; child, 56... First current limiter fixed conductor, 57... Current limiter fixed contact, 58... Resistor, 59...・Support conductor, 60
... Current limiter movable arm, 61... Rotation axis, 62...
- Second current-limiting part fixed conductor, 63... spring, 64...
Movable iron core, 65... Current limiting part movable contact, 66... Fixed iron core, 67... Conductor, 68... Overcurrent train disconnection device, 69... Removable conductor, 70... Breaking part Movable arm, 71...Movable contact of the breaker, 72...Fixed conductor of the breaker, 73...Fixed contact of the breaker, 74...No.
Handle, 75...Pin, 76.77...Exhaust hole, 7
8...Insulating board. Applicant's representative Patent attorney Takehiko Suzue Figure 4 t) U Figure 5 Figure 6 Figure 7 (a) (b) Busy)

Claims (3)

[Claims] (1) A breaker body having a first lead terminal and a short-time overcurrent train disconnection device that trips after a scheduled time delay when a large current flows, and a second lead terminal. a current-limiting section fixed conductor provided with a terminal and a current-limiting section fixed contact; and a current-limiting section fixed conductor that is electrically connected to the breaker main body and corresponds to the current-limiting section fixed contact. A movable contact is provided, and when the current-limiting breaker movable contact and the current-limiting breaker fixed contact are in a closed state, a current-carrying path is formed in the opposite direction to the current-limiting breaker fixed conductor. a rotatable current-limiting part movable contact that forms a parallel conductor together with a part-fixed conductor, and a position where the current-limiting part fixed contact and the second lead-out terminal are provided in the current-limiting part fixed conductor; a fixed iron core provided at an intermediate portion of the fixed iron core, which constitutes an electromagnet part together with the fixed iron core, and which is provided at a predetermined position of the current-limiting breaker movable contact corresponding to the fixed iron core, and the current-limiting breaker A circuit comprising: a movable core that performs a suction operation to open the current-limiting portion fixed contact and the current-limiting portion movable contact when a large current flows through a fixed conductor and the fixed iron core is excited; Breaker. (2) The circuit breaker according to claim 1, wherein the movable iron core is provided at a position where the rotational moment is minimized with respect to the rotation center of the current-limiting breaker movable contact.・ (3) The electromagnetic section has a spring that functions to apply contact pressure to the current-limiting breaker fixed contact and the current-limiting breaker movable contact when not energized and to delay the opening operation when energized. Characteristic Claim No. 1
)Circuit breaker as described in paragraph