JPH03272530A - Vacuum valve for vacuum circuit breaker - Google Patents

Abstract

PURPOSE:To keep a high braking performance constantly by forming a movable contact and a fixed contact in the form of rings, providing each with a slit getting from the outer diameter to the inner diameter of it, and regulating in such a way that a current flowing through the contacts is in one direction so as to set a magnetic field formed by this current to be of the same polarity as that of a magnetic field formed by arc-extinguishing coils. CONSTITUTION:A movable contact 18 and a fixed contact 16 are formed in the form of rings, each is provided with a slit 19, 17 getting from its outer diameter to its inner diameter for regulating that a current flowing through the contacts is in one direction, and it is composed that a magnetic field formed by this current is of the same polarity as that of a magnetic field formed by arc-extinguishing coils 10, 11. The magnetic field of the arc-extinguishing coils is therefore not weakened by being offset but strengthened. Deterioration of a breaking performance according to the arc generation position at the time of a current breakage is thus prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vacuum valve for a vacuum circuit breaker that switches on and off current in a high vacuum, and to the structure of a vacuum valve equipped with an arc-extinguishing coil.

[Conventional technology]

Vacuum circuit breakers open contacts in a high vacuum of about 10-m HI to interrupt current.They are small and lightweight, pose no risk of fire or explosion, and require almost no maintenance and inspection, and are widely used. In particular, those equipped with an arc-extinguishing coil have excellent breaking performance.

FIG. 2 shows an example of the structure of a vacuum valve for a vacuum circuit breaker equipped with a conventional arc-extinguishing coil, in which circular cover plates 2 and 3 are hermetically joined to both ends of a cylindrical insulating tube 1, and this inner space is Maintained under high vacuum. A fixed loft 4 passes through the cover plate 2 and is hermetically joined to the cover plate 2, and a movable rod 6 connects the cover plate 3 via a bellows 5 coaxially attached to the outer circumference of the cover plate 3. It is airtightly joined for axial movement. An arc extinguishing coil 10 and a fixed contact 12 are fixed to the inner end surface of the fixed rod 4 via a connecting conductor 8, and an arc extinguishing coil 11 and a movable contact 13 are fixed to the inner end surface of the movable rod 6 via a connecting conductor 9. The fixed contact 128 and the movable contact 13 constitute a pair of contacts. 7 is an arc shield for adsorbing metal vapor generated when the current is interrupted.

FIG. 3 is an exploded perspective view of the main parts related to the contacts 12 and 13 of FIG. 2, and the detailed structure and function of the contact portions will be explained using this figure.

An axial center portion 8a of a connecting conductor 8 extending in the radial direction is connected to the inner end surface of the fixed loft 4, and an end portion 8b of the connecting conductor 8 is connected to the inner end surface of the fixed loft 4.
It is connected to one end 10a of a ring-shaped arc-extinguishing coil 10. The other end 10b of the arc-extinguishing coil 10 is provided with a convex portion, and this convex portion is connected to the contact 12. The contact 12 is formed into a ring shape so as to equalize the contact pressure and current distribution when energized. Reference numeral 14 denotes a reinforcing body made of an insulating material or a high-resistance material, whose collar is joined to the arc-extinguishing coil IO, and whose cylindrical part has one end connected to the contact 14 and the other end to the connecting conductor 8. Movable rod 6, connection conductor 8, arc extinguishing coil 11. Contact points 13 and reinforcing body 15 are similarly configured. The arc-extinguishing coils IO and 11 are configured to generate magnetic fields in the same direction as indicated by arrows Hlog and Hll.

When this circuit breaker interrupts a large current such as a short circuit current, the magnetic fields HIO and Hll become large values, and the interaction between this magnetic field and the TFI (hereinafter referred to as arc current) IA that flows due to the arc generated between the contacts. This causes an electromagnetic force, and this arc current is diffused and distributed uniformly by the electromagnetic force. This significantly improves the breaking performance of the circuit breaker.The zero arrow indicates the current flow path.

[Problem to be solved by the invention]

When a contact is opened during a current interruption, an arc typically occurs at one location. FIG. 3 shows, for example, a case where an arc occurs between point A of contact 13 and point B of contact 12. This arc causes arc current IA to flow, and this arc current naturally flows through contact 1.
3, but this contact is connected to one point P from the arc-extinguishing coil 11, so if an arc occurs at a point away from the connection point P, the electrician will The current flows through the contact point 13 into a current 1 which flows clockwise and a current I2 which flows counterclockwise and flows to the point where the arc occurs.

In this case, the current 11 flowing clockwise is the arc-extinguishing coil 11.
The current flows in the opposite direction, and acts to cancel the magnetic field H11 generated by the arc-extinguishing coil 11.

Similarly, at the contact 12, the current supplied to the point B by the arc is divided into a current line 3 flowing clockwise and a current line 4 flowing counterclockwise, and flows to the connection point Q with the arc extinguishing coil 10. The electric current generator 3 has a direction opposite to the current flowing through the arc-extinguishing coil 10, and works to cancel the magnetic field HIO generated by the arc-extinguishing coil 10.

As a result, the electromagnetic force caused by the interaction between the arc extinguishing coil's magnetic field and the arc current weakens, reducing the breaking performance of the circuit breaker.

An object of the present invention is to solve the above-mentioned problems and provide a high-performance vacuum valve for a vacuum circuit breaker, which prevents deterioration in interrupting performance due to the position where an arc occurs when current is interrupted.

[Means to solve the problem]

In order to solve the above-mentioned problems, in the present invention, the inside of an insulating tube whose both ends are hermetically sealed by cover plates is maintained at a high vacuum, and an airtight tube is inserted into the insulating tube through one cover plate. A fixed contact is provided on the inner end surface of the fixed rod coupled to the arc-extinguishing coil, and the movable rod passes through the other cover plate and is coupled airtightly to be movable in the axial direction via the bellows. A movable contact is provided on the end face via an arc-extinguishing coil, and the fixed contact and movable contact constitute a pair of contacts, and when the current is interrupted, the arc current generated between these contacts and the magnetic field formed by the arc-extinguishing coil In a vacuum valve for a vacuum circuit breaker that diffuses arc current by electromagnetic force due to the interaction of The current flowing in one direction is defined so that the magnetic field formed by this current has the same polarity as the magnetic field formed by the arc-extinguishing coil.

[Effect]

In the vacuum valve for a vacuum circuit breaker of the present invention, the movable contact and the fixed contact are ring-shaped, and each is provided with one slit extending from the outer diameter to the inner diameter, so that the current flowing through the contact is regulated in one direction, The magnetic field formed by this current is configured to have the same polarity as the magnetic field formed by the arc-extinguishing coil, so no matter which part of the contact an arc occurs, the magnetic field formed by the current flowing through the contact will be the same as the magnetic field formed by the arc-extinguishing coil. It has the same polarity as the magnetic field formed by the arc-extinguishing coil, and although the magnetic field of the arc-extinguishing coil may be strengthened, it will not be canceled out and weakened, thereby preventing a decrease in breaking performance.

(Embodiment) Fig. 1 is an exploded perspective view of the main parts related to the contacts of a vacuum valve for a vacuum circuit breaker in an embodiment of the present invention. The end 8b of the connecting conductor 8 is connected to one end 1081 of the ring-shaped arc extinguishing coil 10.The other end 10b of the arc extinguishing coil 10 is provided with a convex portion. , its convex portion is connected to the contact 16. The contact 16 is ring-shaped and has a slit 17 from its outer diameter to its inner diameter, and the convex portion of the arc-extinguishing coil IO is connected to the contact 16 formed by the slit 17. The movable rod 6 has a connecting conductor 9 extending in the radial direction from the axis (m4#/).
The end 9b of the connecting conductor 9 is connected to the narrow part 9a of the ring-shaped arc extinguishing coil 11, and the other end 11b of the arc extinguishing coil 10 has a convex portion. The protrusion is connected to the contact 18. The contact 18 is ring-shaped and has a slit 17 extending from its outer diameter to its inner diameter, and the convex portion of the arc-extinguishing coil 11 is connected to one end of the contact 16 formed by the slit 19. Now, connect the respective arc extinguishing coils and contacts so that the currents flowing through the contacts 168 and 18 are in the same direction as shown in Figure 1, and the currents flowing through the arc extinguishing coils are in the same direction. Determine the location. By this, when the current is cut off,
No matter which part of the contact an arc occurs, the current flowing through the contact will be in the same direction, and the magnetic field formed by that current will have the same polarity as the magnetic field formed by the arc-extinguishing coil, and the magnetic field of the arc-extinguishing coil will be strengthened. Even if there is, it will not be canceled out and weakened, and the deterioration of the interrupting performance will be prevented.

The other structure and operation are similar to the conventional vacuum valve for vacuum circuit breakers shown in FIGS. 2 and 3.

〔Effect of the invention〕

According to the present invention, in a vacuum valve for a vacuum circuit breaker, the movable contact and the fixed contact are formed into a ring shape, and each is provided with one slit extending from the outer diameter to the inner diameter so that the current flowing through the contact is unidirectional. The magnetic field formed by this current has the same polarity as the magnetic field formed by the arc-extinguishing coil, which prevents the magnetic field of the arc-extinguishing coil from being weakened when the current is interrupted, so it always maintains high interrupting performance. I can do it,
The reliability of the circuit breaker is greatly improved.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the main parts related to the contacts of a vacuum valve for a vacuum circuit breaker according to an embodiment of the present invention, Fig. 2 is a sectional view of a conventional vacuum valve for a vacuum circuit breaker, and Fig. FIG. 2 is an exploded perspective view of the main parts related to the contacts of the vacuum valve for the vacuum circuit breaker shown in the figure. 10.11 ... Arc extinguishing coil 16 ...... Fixed contact 17 ...
......Slit (of fixed contact 16) 18
・・・・・・・・・Movable contact 19 ・・・・・・・・・
...Slit (18 movable contacts) ■ ...
・・・・・・・・・Current

Claims (1)

[Claims] 1) The inside of an insulating tube whose both ends are hermetically sealed by cover plates is maintained at a high vacuum, and arc extinguishing is applied to the inner end surface of a fixed rod that passes through one cover plate and is hermetically coupled to the insulating tube. A fixed contact is provided via an arc-extinguishing coil, and a movable contact is provided via an arc-extinguishing coil to the inner end surface of a movable rod that passes through the other cover plate and is airtightly coupled to be movable in the axial direction via a bellows. The fixed contact and the movable contact constitute a pair of contacts, and when the current is interrupted, the arc current is diffused by the electromagnetic force caused by the interaction between the arc current generated between these contacts and the magnetic field formed by the arc extinguishing coil. In the vacuum valve for a vacuum circuit breaker, the movable contact and the fixed contact are ring-shaped, and each is provided with one slit extending from the outer diameter to the inner diameter so that the current flowing through the contact is unidirectional. A vacuum valve for a vacuum circuit breaker, characterized in that a magnetic field formed by a current has the same polarity as a magnetic field formed by an arc-extinguishing coil.