JPH0322318A - Circuit breaker - Google Patents

Abstract

PURPOSE:To reduce the effect of the magnetic flux of an electromagnetic device and allow the drive of an arc to an arc-extinguishing device with a simple structure by arranging a magnetic shielding plate between the electromagnet device and a pair of contacts. CONSTITUTION:The main flux of the magnetic flux generated by an electromag net device 1 passes a yoke 1d, the leakage flux is distributed between a movable contact 4 and a fixed contact 8, and a large quantity of the leakage flux can be collected by a magnetic shielding plate 10. The magnetic field between the above contacts is made remarkably weak, and the effect on an arc can be reduced. The effect of the magnetic flux of the electromagnet device 1 on the arc can be reduced by only inserting the magnetic shielding plate 10 with a simple structure, thus reliability is improved, the electromagnet device 1 and contacts can be arranged at a small interval, and a circuit breaker can be miniaturized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to improving the breaking performance of a circuit breaker. [Prior art] A conventional circuit breaker is constructed as shown in Figure 3. In the figure, reference numeral 1 denotes an electromagnetic device, which is composed of a coil la wound around a bobbin lb, a fixed iron core 1c, a yoke 1d, a movable iron piece 1e, and a tension spring If. 2 is an opening/closing mechanism that can be operated from the outside of the circuit breaker (details omitted)
A part of it has a movable element 3 and a movable contact 4. 5 is a flexible conductor, and 6 is a terminal board. Reference numeral 7 denotes a stator, to which a fixed contact 8 facing the movable contact 4 is fixed at one end, and the other end is connected to one sunrise wire 1g of the coil la. Reference numeral 9 denotes an arc extinguishing device, which is composed of a support frame 9a and an arc extinguishing plate 9b.
The current path in the above configuration includes the terminal plate 6, the flexible conductor 5, the movable element 3, the movable contact 4, the fixed contact 8, and the coil la. Next, we will explain the operation. When an overcurrent passes through the oval circuit breaker as described above, the magnetic flux due to the current flowing through the coil 1a is distributed to the fixed iron core 1c, the yoke 1d, and the movable iron piece 1.
e as a magnetic path, an electromagnetic force is generated between the movable iron piece 1e and the fixed iron core 1c, and the movable iron piece 1e is rotated clockwise against the force of the tension spring 1f. This operation activates the opening/closing mechanism, releases the contact between the movable contact 4 and the fixed contact 8, and disconnects the circuit. At this time, when the movable contact 4 and the fixed contact 8 are opened, an arc is generated between both contacts, and the arc extinguishing device 9 is a device that breaks up this arc, cools it, and speeds up the extinguishing of the arc. Note that these series of operations are well known. [Problem to be solved by the invention] However, according to the above ellipse, a pair of contact points 4.8
Since the position of the electromagnet device 1 is close to the position of the electromagnet device 1, the magnetic flux generated in the electromagnet device 1 is transferred to the movable contact 4 and the fixed contact 8.
This had the disadvantage that the arc generated during the process prevented the arc extinguishing device from moving in the 9 directions. This invention was made to solve the above-mentioned problems, and its purpose is to reduce the influence of the magnetic flux of the electromagnet device with a simple configuration so as not to impede the driving of the arc to the arc extinguishing device. Suppose that [Means for Solving the Problems] A circuit breaker according to the present invention has a magnetic shielding plate interposed between an electromagnetic device and a pair of contacts. [Function] The magnetic shielding plate in this invention shields the magnetic flux of the electromagnetic device and reduces the influence of this magnetic flux on the arc.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and in the figure, to
is a magnetic shielding plate interposed between the fixed contact 8 and the electromagnetic device 1. Note that the other parts are the same as the conventional device shown in FIG. 3, so their explanation will be omitted. Next, we will discuss its effect. According to the above configuration, the main magnetic flux generated in the electromagnet device 1 passes through the yoke 1d, and the leakage flux is distributed between the movable contact 4 and the fixed contact 8, but this leakage flux is prevented by magnetic shielding. A large amount can be collected on board 10. Therefore, the magnetic field between the contacts mentioned above becomes significantly weaker, so the influence on the arc can be reduced. As shown in FIG. 2, if the surface area of the magnetic shielding plate 10 is increased by providing a groove 10a in the magnetic shielding plate lO, the heat dissipation of the heat generated in the magnetic shielding plate 10 due to iron loss due to the magnetic flux will be improved. You can [Effects of the Invention] As described above, according to the present invention, the influence of the magnetic flux of the electromagnet device on the arc can be reduced by simply interposing a magnetic shielding plate with a simple structure, so that the reliability of the electromagnet is improved and This has the effect of allowing the device and the contacts to be placed close together, allowing the circuit breaker to be made smaller.

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention, FIG. 2 is a perspective view showing a magnetic shielding plate according to another embodiment of the invention, and FIG. 3 is a side view showing a conventional circuit breaker. ．． In the figure, 1 is an electromagnet device, 2 is an opening/closing mechanism, 4 is a movable contact,
8 is a fixed contact, 9 is an arc extinguisher, and 10 is a magnetic shielding plate.

Claims (1)

[Claims] a pair of movable and fixed contacts; an opening/closing mechanism that brings the movable contact into contact with and opens the fixed contact; an arc extinguishing device disposed close to the pair of contacts; What is claimed is: 1. A circuit breaker comprising an electromagnetic device proximate to a pair of contacts, characterized in that a magnetic shielding plate is interposed between the electromagnetic device and the pair of contacts.