JPS63193429A - 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] [Statement of the Invention] (Industrial Application Field) The present invention provides a circuit configured to cause a movable contact to separate using electromagnetic repulsion between a movable contact and a fixed contact. Regarding circuit breaker.

(Prior art) Circuit breakers are basically configured to open the main circuit by displacing the movable contact from the closing position to the open position using a tripping device when an overcurrent is detected. There are many devices that use electromagnetic repulsion to quickly rotate the movable contact away from the fixed contact to improve current limiting and breaking performance. An example of the specific structure is shown in FIG. 6, which will be described below.

Reference numeral 1 denotes a fixed contact fixed in a case 2, one end of which constitutes a terminal connected to the main circuit, and the other end folded back into a U-shape to form a fixed contact 3 at the tip. A movable contact 4 extends from within the tripping device 5, and a movable contact 6 provided at the tip thereof is in pressure contact with the fixed contact 3 of the fixed contact 1. When an overcurrent flows in the main circuit, the movable contact 4 is pulled upward by the tripping device 5 and removed from the open position to I'.
Displaced to the In position. In addition, since the movable contact 4 and the fixed contact 1 are arranged in parallel and the current flows in opposite directions in the opposing parts, when a large fault current flows, the gap between the movable contact 4 and the fixed contact 1 An electromagnetic repulsive force acts on this, and the movable contact 4 rotates away from the fixed contact 1 without waiting for the tripping device 5 to operate! j1 current is quickly limited. Here, in order to increase the separation speed of the nll contactor 4 and achieve faster current limiting, conventionally, a U-shaped magnetic driving iron core 7 as shown in FIG. Children 1 and 4 were placed in such a way that they were sandwiched from the sides.

By the way, in such a configuration, it is clear that the separation speed of the movable contact 4 depends on the difference in magnetic flux density between the upper and lower spaces of the movable contact 4, and the greater the difference in magnetic flux density, the greater the separation speed. be. However, in the above-mentioned magnetic driving iron core 7, since the upper part is open, the space between the upper side portions 7a constitutes a part of the magnetic circuit. For this reason, the magnetic flux density in the four-way space of the ++J moving contact does not become sufficiently small, and the difference in magnetic flux density between the upper and lower spaces of the movable contact 4 is small, so the separation speed of the movable contact 4 cannot be sufficiently increased. I couldn't do it.

Therefore, in order to reduce the magnetic flux density in the space above the movable contactor 4 as much as possible, a closed loop structure is used in which the -L portion of the side portion 7a of the magnetic drive core 7 is connected by a connecting portion 8a as shown in FIG. It is conceivable to use a magnetic driving iron core 8.

According to this, the magnetic flux in the − direction of the movable contactor 4 is concentrated at the connecting portion 8a in the upper part of the magnetic drive core 8, so that
The magnetic flux density in the one-way space of the movable contact 4 is significantly reduced, and the separation speed of the movable contact 4 can be sufficiently increased.

However, in this configuration, the upper part of the magnetic driving core 8 is connected by the connecting part 8a, so when assembling the circuit breaker, the connecting part 8a of the magnetic driving core 8 gets in the way of the assembly, resulting in poor productivity. This results in the disadvantage that the amount of water decreases.

(Problems to be Solved by the Invention) As mentioned above, in the conventional configuration using the U-shaped drive core 7, the separation speed of the movable contact 4 is not sufficient, and in order to improve this, a closed loop structure is used. If the magnetic drive core 8 is used, there is a problem in that the ease of assembly is significantly reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a circuit breaker that can increase the separation speed of a movable contact in the event of an accident to enable rapid current limiting, without impairing assemblability.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a magnetic drive core having a substantially U-shape and having a pair of side portions extending along the approaching and separating directions of the movable contact T. Prepare for an accident? In the device in which the J moving contact is rotated away from the fixed contact based on the electromagnetic repulsion force generated by the 'li flow, an insulating layer is formed on the surface of the magnetic driving iron core, and an arc extinguishing grid is formed. The present invention is characterized in that a plate is provided adjacent to or in contact with at least a portion of the side portion of the driving iron core so as to be continuous with a small magnetic resistance.

(Function) When a fault current flows in the main circuit, magnetic flux is distributed around the movable contact and the fixed contact, and an electromagnetic repulsive force acts between the movable contact and the fixed contact. At this time, the magnetic flux above the movable contact is concentrated on the grid plate connected to the magnetic driving iron core with a small magnetic resistance, so that the magnetic flux density in the space above the movable contact is extremely reduced. As a result, the difference in magnetic flux density between the upper and lower spaces of the movable contact becomes large, and the electromagnetic repulsion force increases significantly, so that the separation speed of the movable contact is increased compared to the conventional one. Further, since the upper part of the magnetic drive core is open, the magnetic drive core does not get in the way when assembling the circuit breaker.

(Example) Hereinafter, a first example of the present invention will be described with reference to FIGS. 1 to 3. A fixed contact 11 is fixed to the case 12, one end of which is connected to the main circuit outside the case 12, and a fixed contact 13 is provided at the other folded end. Reference numeral 14 denotes a movable contact, which extends from within the tripping device 15 in parallel with the fixed contact 11, and a movable contact 16 provided at the tip of the movable contact 14 contacts the fixed contact 1 of the fixed contact 11.
It is possible to move towards and away from 3. When a fault current flows through the main circuit, the movable contactor 14 is pulled upward from the closed circuit position by the tripping device 15 and displaced to the open circuit position.

Although not shown, the base end of the movable contact 14 is provided so as to be rotatable relative to the tripping device 15, so that when a fault current flows, the electromagnetic repulsive force This causes the contact 11 to rotate away from the fixed contact 11. Now, 17 is a U-shaped magnetic drive core,
A pair of side portions 17a are provided so as to sandwich the inner contact 11.14 from the sides, and the pair of side portions 17a are provided so as to sandwich the inner contact 11.
a.

17a extends in the direction in which the movable contact 14 approaches and separates.

An insulating layer (not shown) is formed on six surfaces of the magnetic driving iron core 17 by flow coating with, for example, epoxy resin. 18 is a large number of arc extinguishing grid plates;
These have a U-shaped opening 18a for passing an arc generated when the movable contact 14 is opened.
A pair of notches 18b are formed on both sides of the open end of a. As shown in FIG. 1, these grid plates 18 are arranged so that the side part 17a of the magnetic drive core 17 is located within the notch 18b and close to this, with a gap of approximately l mn or less. In this state, the magnetic driving iron core 17 and the grid plate 18 are electrically insulated, but magnetically connected with low magnetic resistance.

Next, the operation of the above configuration will be explained. For example, short circuit/I
If failure C occurs and a short circuit current flows through the movable contact 14 and the fixed contact 11 in the opposite directions shown by the arrows in FIG. Magnetic fluxes are generated in the directions shown in FIG. 3, respectively. The magnetic flux generated by the current flowing through the movable contact 14 is concentrated on the magnetic drive core 17 on both sides of the movable contact 14, and on one side of the movable contact 14, the magnetic flux is concentrated in the magnetic drive core 17 as shown by the arrow in FIG. It concentrates on the grid plate 18 which is approximately in contact with the grid plate 17. Therefore, the magnetic flux density in the space above the movable contact 14 becomes sufficiently small, and as a result, the difference in magnetic flux density in the space above and below the movable contact 14 increases, and the movable contact 14 receives a large electromagnetic repulsive force and is quickly fixed. It separates from the contactor 11. As a result, I'll move the moving contact 14 and the fixed contact 1.
1, the arc length rapidly increases, so the fault current is quickly limited without waiting for the tripping device 15 to complete the interruption.

Furthermore, since there is no need to connect the open portion at the upper part of the magnetic drive core 17, the magnetic drive core 17 may become an obstacle when assembling a circuit breaker using the magnetic drive core 17. do not have.

FIG. 4 shows a magnetic drive core 19 according to a second embodiment of the present invention, which differs from the first embodiment in that the upper end of a side portion 20a of a U-shaped magnetic drive core body 20 is A connecting portion 21 that bypasses the open portion is integrally provided in contact with the connecting portion 21, and this connecting portion 21 is also used as a part of the grid plate 18 group. Note that this embodiment is similar to the first embodiment in that an insulating layer is formed on the entire surface of the magnetic drive core body 20 and the connecting portion 21 by flow coating. When this magnetic drive core 19 is used, the upper open part of the side part 20a of the magnetic drive core main body 20 is bypassed and connected by the connection part 21, so that it is different from that of the first embodiment. Compared to this, the magnetic resistance between the magnetic drive core body 20 and the connecting portion 21 becomes even smaller, and as a result, the movable contact 1
The difference in the magnetic flux density between the upper and lower spaces of 4 can be further increased, and the separation speed of the movable contact can be further increased. in this case,
Since the magnetic resistance of the magnetic path passing through the connecting portion 21 is extremely small, the other grid plates 18 may be located further away from the magnetic drive core body 20 than in the first embodiment.

Further, in the present invention, the fixed contact 22 is rotatably provided as shown in FIG. 5, and the fixed contact 22 is also rotated in the opposite direction to the contact direction of the movable contact 14 due to electromagnetic repulsion caused by the fault current. You may also do so.

In addition, the present invention is not limited to what has been described above and shown in the drawings, and can be practiced in various ways without departing from the scope of the invention.

[Effects of the Invention] As is clear from the description in -1- below, the present invention includes a grid plate for arc extinguishing with a small magnetic resistance on a magnetic driving iron core provided along the direction of approach and separation of the movable contact. Since they are provided close to each other or in contact with each other, the magnetic flux density in the space above the movable contact becomes sufficiently small, and the difference in magnetic flux density in the space above and below the movable contact becomes sufficiently large compared to the conventional one. Therefore, the separation speed of the movable contactor is dramatically improved, resulting in excellent current limiting and
A shielding effect can be obtained.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a plan view showing the main parts broken away, FIG. 2 is a front view showing the main parts broken away, FIG. 3 is a longitudinal cross-sectional side view of the main part along the line ■-■ in FIG. 2, and FIG.
FIG. 5 is a perspective view of a magnetic drive core showing another embodiment, FIG. 5 is a view equivalent to FIG. 2 showing another embodiment, FIGS. 6 to 8 show conventional examples, and FIG. Figure equivalent figures, Figures 7 and 8
The figure is a perspective view of the magnetic drive core. In the figure, 11 is a fixed contact, 14 is a movable contact, 17 is a magnetic drive core, 17a is a side part, 18 is a grid plate, 1
9 is a magnetic drive iron core, 20a is a side part, 21 is a connecting part,
22 is a fixed contact.

Claims (1)

[Claims] 1. A fixed contact, a movable contact that approaches and separates from the fixed contact, and a pair of side portions that extend along the direction of contact and separation of the movable contact, forming a substantially U-shape. A magnetic drive core is provided, and the movable contact is rotated away from the fixed contact based on electromagnetic repulsion caused by an accident current, wherein an insulating layer is formed on the surface of the magnetic drive core; A circuit breaker characterized in that an arc-extinguishing grid plate is provided adjacent to or in contact with at least the upper part of the side portion of the driving iron core so as to be continuous with a small magnetic resistance. 2. The circuit breaker according to claim 1, wherein the magnetic drive core has a connecting portion on the upper portion that bypasses the open portion between the side portions and magnetically connects both side portions.