JP3357963B2 - Circuit breaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker having a voltage trip device, and more particularly to a circuit breaker suitable for preventing the voltage trip device from being burned out by a large current.

[0002]

2. Description of the Related Art As a prior art of a circuit breaker having a voltage trip device, there is one disclosed in Japanese Patent Application Laid-Open No. 1-79250. The prior art has a switch that cuts off current to a coil of a voltage trip device,
When a voltage is applied to the coil, the mechanism of the circuit breaker trips when the plunger is attracted to the coil, and the switch is turned off by the tripping operation. Of the coil is not burned.

[0003]

The above-mentioned prior art is intended to prevent burnout of the voltage trip device, but may be used for a device in which a large current or a high voltage of a DC power supply flows in the main circuit. Can not. That is, since the switch of the prior art uses a microswitch, it can be operated only with a small current, so that it cannot be used for a device that conducts a large current or the like.

In view of the above circumstances, an object of the present invention is to provide a circuit breaker that can reliably prevent a voltage trip device from burning even when a large current or a high voltage such as a DC power supply flows. is there.

[0005]

SUMMARY OF THE INVENTION According to the present invention, there is provided an opening / closing mechanism which comprises a main contact for opening and closing a main circuit, a toggle link portion, and which can be opened and closed by tripping when the main contact is closed. An overcurrent tripping mechanism that detects an overcurrent flowing in the main circuit and trips the switching mechanism, and a voltage tripping device that cuts off a current flowing through the coil when a voltage is applied to the voltage tripping coil. A circuit breaker having a mechanism for tripping an open / close mechanism by an attractive force to the coil when the voltage trip coil is energized; and a circuit breaker made of the same member as the main contact and connected to a voltage trip device, and It has a contact for a voltage trip device that can be opened by a trip operation of the mechanism.

[0006]

In the present invention, as described above, when a voltage is applied to the voltage trip device when the main contact is closed, the mechanism trips the switching mechanism, so that the contact for the voltage trip device is opened. Let go. As a result, the contacts are opened at the same time as the main circuit is tripped, so that the current can be prevented from flowing through the voltage release coil, and the coil can be prevented from burning. Therefore, even if a large current that cannot be dealt with by the microswitch flows through the voltage trip device, it is possible to reliably prevent the voltage trip coil from burning. Further, since the contact is made of the same member as the main contact, the timing of the cutoff operation of the voltage trip device and the trip operation between the main contacts become the same, and the operation time is short, so that the responsiveness is extremely good. In addition, since the contact pressure is the same as that of the main circuit, high contact reliability can be obtained for a long time.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. 1 to 4 show an embodiment in which the circuit breaker of the present invention is connected to a DC power supply. As shown in FIG. 1, the circuit breaker according to the embodiment has a main contact in a space formed by a case 1 and a cover 2 assembled thereto. The main contact is composed of a fixed contact 5 brazed to a fixed contact base 4 and a movable contact 6 brazed to a movable contact base 7. The circuit is closed and the main circuit is opened by moving the movable contact 6 away from the fixed contact 5. More specifically, as shown in FIGS. 1 and 2, the fixed contact base 4 is composed of two fixed ends, which are screwed to both sides of the outer left end of the case 1.
One of them is connected to the positive pole on the DC power supply side and the other is connected to the negative pole, and the fixed contact 5 is brazed to the other end located inside the case 1. The movable contact stand 7 is supported by a shaft 9 inside the case 1, one end of which is connected to a load terminal 31 via a wiring (not shown), and the movable contact 6 is brazed to the other end. Further, the movable contact stand 7 is urged by the contact spring 8 toward the fixed contact stand 4 (counterclockwise). The load terminals 31 are screwed to both sides of the outer right end of the case 1 and connected to a load. An overcurrent tripping mechanism and an opening / closing mechanism are provided in the space formed by the case 1 and the cover 2 to trip the main contact. The overcurrent tripping mechanism is not shown in detail, but is connected to the movable contact block 7 and can generate heat when an overcurrent flows.
As shown in FIG. 6, when the bending operation is performed by the heat of the heating element, a bimetal 40 for pressing an opening / closing mechanism described later in a trip operation direction is used.
(See FIG. 2). As shown in FIGS. 1 and 2, the opening and closing mechanism includes a movable core 23b, an interlocking shaft 22, a relay shaft 21, a trip lever 19, a trip fitting 17,
Hook 13, lever 12, lever lower 15, drive spring 1
1, a normal toggle link having a con axle 26, etc., is configured to perform a trip operation. That is, when the interlocking shaft 22 rotates counterclockwise, the relay shaft 21 responds clockwise with the shaft 20 of the trip lever 19 as a fulcrum, and the trip fitting 17 resists the spring force of the return spring 18 by the response. The hook 13 is disengaged from the hook 13 by operating clockwise, and the hook 13 is rotated counterclockwise about the hook shaft 16 by the spring force of the drive spring 11 so that the lever 12 moves upward and the lever 12 With this movement, the lower shaft 15 moves in the clockwise direction via the pin 14 and the common shaft 26 common to the respective poles moves in the clockwise direction. Are separated from the fixed contact 5. At this time, the connecting shaft 26 is integrally formed so as to be common to the respective poles, and its movement interrupts the main circuit of both poles. When the main circuit is interrupted by the trip operation, the operation handle 3 is positioned in the direction of the arrow in FIG. 1. The main circuit is closed again. Further, a voltage trip device 24 is provided in the space between the case 1 and the cover 2.
The voltage tripping device 24 prevents the burnout of the voltage tripping coil 28 by tripping the opening / closing mechanism when a voltage is applied thereto by a power source different from the main circuit. . More specifically, as shown in FIG. 1 and FIG.
A fixed contact stand 4a similarly formed is installed between the movable contact stands 7, and a movable contact stand 7a similarly formed between the movable contact stands 7, 7 is installed. 7a
The movable contact 6 and the fixed contact 5 are respectively brazed to and the fixed contact stand 4a. Further, the movable contact stand 7a is incorporated in the con shaft 26 so as to be common to each of the movable contact stands 7 described above. On the other hand, the fixed contact stand 4a and the movable contact stand 7a have
As shown in FIG. 3, the voltage trip device 24 is connected via the connection lines 33 and 32, and the voltage trip device 24 is connected to the voltage trip device 24.
Is connected to another power source. Accordingly, the contact between the fixed contact stand 4a and the movable contact stand 7a forms a closed circuit between the voltage trip device 24 and another power supply.

As shown in FIG. 3, the voltage release device 24 has the movable core 23 engaged with the neck at the tip of the plunger 25 and the movable core 23
The extension 23a extending upward is connected by a tension spring 27, and applies a clockwise urging force to the movable core 23. The urging force is, as shown in FIG.
The third extension 23a is almost in contact with the drive shaft 22 of the opening / closing mechanism. When a voltage is applied to the voltage trip device 24, the plunger 25 is attracted to the fixed core 30 by exciting the voltage trip coil 28, and the movable core 23 is connected to the plunger 25 by the attracting action. Pivots counterclockwise around the engagement part of
The movable core 23 pushes the interlocking shaft 22 of the opening / closing mechanism in the trip direction to cut off the main circuit, thereby cutting off the current supply to the voltage trip coil 28. In this example, the voltage trip coil 28
As a means for interrupting the current supply, a three-phase circuit breaker is used, and the circuit breaker is opened by using a vacant one-phase (S-phase) fixed contact block and movable contact block. 1 and 2, reference numeral 31 denotes an arc chute.

The circuit breaker of the embodiment has the above-described configuration, and its operation will be described next. When the main contact is closed, the movable contact 6 of the movable contact base 7a comes into contact with the fixed contact 5 of the fixed contact base 4 so that the voltage trip device 2
4 is also in a state where a closed circuit is formed for another power supply. At this time, when a voltage is applied to the voltage trip device 24, the plunger 25 is attracted by exciting the voltage trip coil 28, and the movable core 23a rotates counterclockwise by the attraction action of the plunger 25. And the movable core 23
Pushes the interlocking shaft 22 of the opening / closing mechanism in the trip direction, and the control shaft 26 moves counterclockwise, so that the movable contact stand 7a operates in the same manner as the movable contact stand 7 together. As a result, the main circuit is tripped, and
Since the contact between a and the fixed contact stand 4a is separated, it is possible to block the current from flowing through the voltage trip coil 28 and prevent the coil 28 from burning. Therefore,
Even if a large current that cannot be dealt with by the microswitch flows through the voltage trip device 24, it is possible to reliably prevent the voltage trip coil 28 from burning. Furthermore, since a three-phase circuit breaker is used for the DC circuit, and the S-phase fixed contact block 4a and the movable contact block 7a that are not used are used to form the contacts of the voltage trip device 24, The same members as the fixed contact stand 4 and the movable contact stand 7 whose contacts form the main contact are used. Therefore, the timing of the interruption operation of the voltage trip device 24 and the timing of the trip operation between the main contacts become the same, and the operation time is short, so that the responsiveness is extremely good. In addition, since the contact pressure is the same as that of the main circuit, high contact reliability can be obtained for a long time. Therefore, even if the current region flowing through the coil 28 is greatly expanded, the cutoff function can be performed accurately. Further, in the illustrated embodiment, since a three-phase circuit breaker is used in the DC circuit, it is only necessary to improve a part of the structure of the circuit breaker, which can be easily dealt with. In the present invention, the present invention is not limited to the illustrated embodiment, and can be used for a three-phase power supply. That is, if a set of a fixed contact block and a movable contact block corresponding to each main contact of the three-phase circuit and a voltage trip device connected thereto is added, it can be surely applied to the three-phase circuit. Can be.

[0010]

As described above, according to the present invention, when a voltage is applied to the voltage trip device, the main contact is formed in the same manner as that of the main contact by using the opening / closing mechanism for separating the main contact. Since the voltage trip contact is opened to cut off the current to the voltage trip coil, even if a large current that cannot be handled by the microswitch flows, the voltage trip coil can be reliably prevented from burning. In addition, even if the current region flowing through the coil is greatly expanded, there is an effect that the cutoff function can be properly performed.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an embodiment in which a circuit breaker of the present invention is connected to a DC power supply.

FIG. 2 is an explanatory plan view showing a state where a cover of the circuit breaker of the present invention is removed.

FIG. 3 is an explanatory perspective view showing a main part of the present invention.

FIG. 4 is a circuit diagram of a circuit breaker.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 2 ... Cover, 4 ... Fixed contact stand, 5 ... Fixed contact, 6 ... Movable contact, 7 ... Movable contact stand, 4a ... Fixed contact stand, 7a ... Movable contact stand, 24 ... Voltage release device, 25
... Plunger, 28 ... Voltage trip coil, 23 ... Movable core, 40 ... Bimetal.

Claims (1)

(57) [Claims] 1. A main contact for opening and closing a main circuit, an opening / closing mechanism which constitutes a toggle link portion and which can open and close the main contact by tripping when the main contact is closed, and an overcurrent flowing in the main circuit. And a circuit breaker having an overcurrent tripping mechanism that trips the switching mechanism and a voltage tripping device that shuts off the current flowing through the coil when a voltage is applied to the voltage tripping coil. A mechanism for tripping the opening / closing mechanism by an attractive force to the coil when energizing the tripping coil, the main contact being made of the same member as the main contact, being connected to the voltage tripping device, and being able to be opened by the tripping operation of the switching mechanism; A circuit breaker having a contact for a voltage trip device.