JPH03246840A - Vacuum valve - Google Patents

Abstract

PURPOSE:To reduce the power loss at the time of excitation by providing a reinforcing member connected to an exciting shaft and inserted into a coil electrode and having a positive resistance temperature coefficient between the exciting shaft and the back face of an electrode. CONSTITUTION:A reinforcing member 6 connected to an exciting shaft 5 and inserting into a coil electrode 4 and having a positive resistance temperature coefficient is provided between the exciting shaft 5 and the back face of an electrode 1. The reinforcing member 6 arranged between the back face of the electrode 1 and the exciting shaft 5 prevents the deformation of the electrode 1 and the coil electrode 4, the reinforcing member 6 has a high resistance value due to the cutoff current at the time of a cutoff, thus a current flows in the coil electrode 4, and a current flows in the reinforcing member 6 having a low resistance value at the time of excitation. The power loss on the current path of the coil electrode 4 at the time of excitation can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vacuum valve that can reduce power loss when energized (closed).

(Prior Art) Vacuum valves for interrupting large currents generally have a vertical magnetic field electrode structure that generates an axial magnetic field between electrodes.

This vertical magnetic field electrode uses an axial magnetic field to disperse the arc uniformly between the electrodes during current interruption, thereby preventing concentration of the arc and melting of the electrode, thereby improving the interruption performance. Furthermore, the reinforcing member between the electrode and the current-carrying shaft is made of stainless steel.

(Problems to be Solved by the Invention) In the vertical magnetic field electrode structure of the vacuum valve as described above, since the reinforcing member has a large resistance value, current always flows through the coil electrode during energization and energization. Furthermore, since the current path of the coil electrode is long, the resistance value of the coil electrode is large. Therefore, there is a problem in that power loss increases when a large current is applied.

An object of the present invention is to provide a vacuum valve that can reduce power loss during energization (when closed) without reducing the interrupting performance.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a connection from the current-carrying shaft to the back surface of at least one of a pair of electrodes that are provided in a vacuum container so as to be able to come and go and are attached to the current-carrying shaft. In a vacuum valve having a coil electrode, the reinforcing member has a positive temperature coefficient of resistance and is connected to the current-carrying shaft and fitted into the coil electrode between the current-carrying shaft and the back surface of the electrode.

(Function) The reinforcing member between the back of the electrode and the current-carrying shaft prevents deformation of the electrode and coil electrode, and when energized, the reinforcement member has a low resistance when energized, so the breaking current at the time of interruption becomes high resistance, and the breaking current flows to the coil electrode. , it is possible to reduce power loss during energization without reducing interrupting performance.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an electrode of a vacuum valve according to the invention.

The lower side of the figure shows the movable side, and the upper side shows the fixed side.

1 is an electrode, and a contact point 2 is fixed to the surface of the electrode 10.

A connector 3 is fixed to the back surface of the electrode 1 on the opposite side from the contact 2.

Reference numeral 4 denotes a coil electrode, which has a plurality of arm portions (not shown) extending radially from the current-carrying shaft 5, and the protruding ends of each of these arm portions are directed toward each other, and the tips thereof are arranged with appropriate gaps between the protruding ends of the adjacent arm portions. It consists of a coil portion drawn in circular arcs in the same direction, and is connected to the electrode 1 via a connector 3.

Mainly when the current is cut off, a longitudinal (axial) magnetic field is generated to uniformly disperse the arc between the electrodes, thereby preventing concentration of the arc and melting of the electrodes. Further, the coil electrodes of the opposing fixed side electrodes have a similar structure so that a uniform magnetic field is generated between the electrodes.

A reinforcing member 6 prevents deformation of the electrode 1 and the coil electrode 4 due to external force applied when the electrodes are opened and closed.

Therefore, it is fitted into the insertion hole of the coil electrode 4 together with the upper part of the energizing shaft 5 to be connected and brazed, and is connected to the electrode 1. The material of the reinforcing member 6 is selected so that the current flows through the reinforcing member 6 when the current is applied and the coil electrode 4 generates a magnetic field sufficient to uniformly disperse the arc when the current is interrupted. For example, V2O3 ceramic,
Characteristics with a positive temperature coefficient of resistance (PTC characteristics) such as
If this material is used, current will flow to the reinforcing member 6 because it has low resistance when current is applied, and to the coil electrode 4 because it has high resistance when current is interrupted. In this way, a sufficient change in resistance can be obtained from the time of energization to the time of energization, so it is not necessary to use a cylindrical shape simply to increase the resistance value, but a cylindrical shape may be used.

Next, the action of this vacuum pulse will be explained with reference to FIG.

FIG. 2 shows the characteristics showing the change in resistance value with respect to the applied current when the reinforcing member 6 is made of V203 ceramic. The resistance value of the reinforcing member 6 is approximately 0.0 at around the rated current value IRC.
5 [μg], which is sufficiently smaller than the resistance value of the coil electrode 4. Therefore, most of the current when energized flows through the reinforcing member 6, so that the power loss of the coil electrode 4 is small and is almost unaffected by the length of the current flow path. In addition, heat generated by the current flowing through the reinforcing member 6 and heat generated by contact resistance during energization (when closed) can be removed by heat conduction because the reinforcing member 6 is formed into a columnar shape.

Furthermore, as the applied current increases, the resistance value of the reinforcing member 6 also increases, and when the rated breaking current Iri is reached, the resistance value of the reinforcing member 6 becomes approximately 50 [μΩ], which is sufficiently larger than the resistance value of the coil electrode 4. Therefore, since the current flows through the coil electrode 4, a sufficient magnetic field can be obtained to interrupt the current.

Although the magnetic field generated between the electrodes is small in the intermediate region between the rated energizing current IrC and the rated breaking current Iri, breaking is possible within this current range.

〔Effect of the invention〕

According to the present invention, when the current is turned off, current flows through the reinforcing member with a high resistance value due to the breaking current, and when the current is applied, current flows through the reinforcing member with a low resistance value, so that the current path of the coil electrode when the current is applied. power loss can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the vacuum valve of the present invention, and FIG. 2 is a graph showing the change in resistance value of the 203 ceramic according to the present invention with respect to the applied current. 2...Contact...Coil electrode 6...Reinforcement member

Claims (1)

[Scope of Claims] A vacuum valve having a coil electrode connected from the current-carrying shaft to the rear surface of at least one of a pair of electrodes that are detachably provided in a vacuum container and attached to the current-carrying shaft, comprising: A vacuum valve characterized in that a reinforcing member having a positive temperature coefficient of resistance is provided between back surfaces of electrodes, the reinforcing member is connected to the current-carrying shaft and fitted into the coil electrode.