RU2567115C1 - Vacuum circuit breaker - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: vacuum circuit breaker comprises arc-quenching chamber with axial movable and fixed electrodes complete with ring contacts. The electrodes are fixed to the chamber body, at that the movable electrode is fixed by means of current lead and metal corrugated tube. Inside the arc-quenching chamber, at the contact level, a cylindrical shield is mounted. From outside from the fixed electrode side, at the level of gap with contacts, a permanent magnet is fixed by means of a dielectric ring to the chamber body. The above magnet is made as a ring magnetized radially thus forming between contacts a field radial cross to the axis.

EFFECT: increased intensity of magnet field between ring contacts, improvement of switching performance.

1 dwg

Description

The invention relates to electrical engineering, namely to power switching equipment and is intended for use in vacuum circuit breakers and contactors of direct and alternating current.

Known vacuum current switch [RU 2230385 C2, IPC 7 H01H 33/664, publ. 2004.06.10], comprising an arcing chamber with axial movable and fixed electrodes with end contacts fixed to the camera body, and a magnetic system forming a field transverse to the axis between the contacts. The magnetic system, made in the form of a permanent magnet, is located along the axis from the side of one of the contacts and is made forming a transverse radial field. The magnet is made in the form of a ring, the part of the housing in contact with the magnet is made of ferromagnetic material.

The disadvantage of this vacuum circuit breaker is the design of the central part of the camera housing located inside the fixed electrode with an annular contact. This part of the housing is electrically connected to a fixed contact, and the magnetic field near it is perpendicular to it, since it is axial in nature. The arc arising between the contacts when they open is pushed out of the working gap and can stably burn between the central part of the movable electrode and the central part of the housing located inside the stationary contact, since the electric and magnetic fields are parallel to the axis. Thus, the switching characteristics of the circuit breaker deteriorate: the value of the switching current decreases and the time of interruption of the arc increases.

The closest adopted for the prototype is a vacuum circuit breaker [RU 2400855 C1, IPC Н01Н 33/664 (2006.01), publ. 2010.09.27], containing an arcing chamber with axial movable and fixed electrodes equipped with ring contacts. The electrodes are attached to the camera body, and the movable electrode is attached using current lead and corrugation. Coaxial to the ring contacts on the side of the stationary electrode is a magnetic system containing a permanent magnet, and forming a field between the contacts of the transverse radial axis. In a fixed ring contact from the side of its attachment to the electrode, radial grooves are made uniformly spaced around the circumference, in which U-shaped permanent magnets are located, isolated from the fixed electrode and the fixed ring contact. The contact surface of the ring contacts along the axis of the electrodes is located at the level of the plane of the poles of the magnets.

The disadvantage of this vacuum circuit breaker is the low magnetic field strength between the contacts.

The objective of the invention is: an increase in the magnetic field in the contact gap, a decrease in electrical discharge erosion of the contacts, and an improvement in switching characteristics.

The problem is solved due to the fact that the vacuum current switch, as in the prototype, contains an arcing chamber with axial movable and fixed electrodes equipped with ring contacts, the electrodes are attached to the camera body, and the movable electrode is attached using a current lead and a metal corrugation, a permanent magnet forming a field between the contacts of the transverse radial axis.

According to the invention, a cylindrical screen is fixed inside the arcing chamber at the level of the arrangement of contacts. Outside, a permanent magnet in the form of a radially magnetized ring is attached by means of a dielectric ring to the body of the arcing chamber, on the side of the fixed electrode, at the level of the location of the gap between the contacts.

The proposed placement of a permanent magnet in the form of a radially magnetized ring outside the chamber at the level of the location of the gap between the contacts allows to increase the magnetic field strength between the ring contacts. The result of this is an improvement in switching characteristics: the service life of the circuit breaker is extended and the time of interruption of the arc is reduced, and therefore, the erosion of the contacts is reduced.

In FIG. 1 schematically shows a vacuum circuit breaker.

The vacuum current switch contains a housing 1, separated by a high-voltage insulator 2, forming an arcing chamber with axial movable 3 and fixed 4 electrodes. A movable electrode 3 is attached to the upper part of the housing 1 by means of a current lead 5 and a metal corrugation 6, which separates the vacuum medium of the chamber from the environment. The fixed electrode 4 is attached by a current lead 7 to the lower part of the body 1 of the arcing chamber. The electrodes 3 and 4 are provided with ring contacts 8 and 9. The electrodes 3 and 4 can be made of highly conductive material, for example, copper. The ring contacts 8 and 9 can be made of non-magnetic material, for example, molybdenum. Inside the body 1 of the arcing chamber, at the level of the location of the contacts 8 and 9, a cylindrical screen 10 made of copper is fixed. Outside, to the body 1 of the arcing chamber, on the side of the fixed electrode 4, at the level of the location of the gap between the contacts 8 and 9, a permanent magnet 12 in the form of a ring that is radially magnetized is attached using a dielectric ring 11. Magnet 12 can be made on the basis of samarium-cobalt.

The vacuum circuit breaker operates as follows.

When the ring contacts 8, 9 are closed, an electric current flows from the current lead 5 through the movable 3 and fixed 4 electrodes. The magnet 12 generates a magnetic field radial relative to their axis in the plane of the junction of the movable ring contact 8 and the stationary ring contact 9. When the ring contacts 8 and 9 are opened between them, an electric arc lights up, while the metal corrugation 6 is compressed and the tightness of the arcing chamber is ensured. Mechanical forces on the arc arising from the interaction of the electric current of the arc and the transverse magnetic field move it along the contacting surface of the ring contacts 8 and 9. Under the action of centrifugal force, the arc moves along the radius and is pushed out of the gap between these contacts. Thus, the arc does not locally overheat the contacting surface of the ring contacts 8 and 9, which ensures their uniform and minimal wear. Moving, the arc quickly cools and goes out.

Claims (1)

A vacuum current switch containing an arcing chamber with axial movable and fixed electrodes provided with ring contacts, the electrodes are attached to the camera body, the movable electrode being attached by means of a current lead and a metal corrugation, a permanent magnet forming a field between the contacts of the radial axis, characterized in that inside the arcing chamber, at the level of the location of the contacts, a cylindrical screen is fixed, and outside to the body of the arcing chamber, from the stationary ektroda at location level gap between contacts is attached by means of a dielectric ring-shaped permanent magnet is radially magnetized ring.