JP2892457B2 - Vacuum valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a vacuum valve that obtains excellent shut-off performance without deteriorating energization performance.

(Prior Art) The shutoff performance of a vacuum valve depends on the radial distribution of the magnetic field strength generated between the electrodes, and the flatter the radial distribution, the better the shutoff performance.

In a conventional vacuum valve, a coil electrode provided on the back surface of the electrode includes a first coil for generating an axial magnetic field, and a second coil for generating a magnetic field opposite to the axial magnetic field generated by the first coil. By superposing these magnetic fields, the magnetic field intensity at the center of the electrode is reduced, and the magnetic field distribution in the radial direction is flattened.

(Problems to be Solved by the Invention) In the conventional vacuum valve, the current path of the coil electrode becomes long, so that the current-carrying performance is deteriorated, which is not suitable for increasing the capacity.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vacuum valve which enables prediction by calculation and which is excellent in shut-off performance without reducing current-carrying performance.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention has a fixed electrode and a movable electrode which are disposed in a vacuum vessel so as to be able to freely contact and separate from each other. In a vacuum valve provided with a coil electrode for generating a magnetic field, a one-turn coil electrode is provided on the back of both electrodes separately from the coil electrode and generates a magnetic field by an induced voltage from the coil electrode to reduce the magnetic field at the center of the electrode. That is the gist.

(Operation) In such a configuration, the back surface of the fixed electrode and the movable electrode and a one-turn coil are provided, and the shape of the one-turn coil is determined by predicting in advance by a magnetic field generated by an induced voltage from the coil electrode, and is generated between the two electrodes. Since the magnetic field distribution in the radial direction is flattened, the breaking performance can be improved without lowering the current-carrying performance.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an electrode portion of a vacuum valve of the present invention. Here, the movable side will be described and the fixed side will be omitted.

Reference numeral 1 denotes a contact and reference numeral 2 denotes an electrode, and a slit is sufficiently provided so that eddy current induced by the coil electrode 5 is suppressed.

Reference numeral 3 denotes a connector, and reference numeral 4 denotes a reinforcing member, which connects the coil electrode 5 for generating an axial magnetic field to the electrode 2. The connector 3 is provided substantially at the rear end of the electrode 2, and the reinforcing member 4 is provided substantially at the center of the rear of the electrode 2.

 Reference numeral 6 denotes an energizing shaft.

Reference numeral 7 denotes a one-turn coil which is provided on the back surface of the electrode 2 and at an intermediate portion between the connector 3 and the reinforcing member 4, and prevents a gap between the reinforcing member 4 and the inner diameter of the one-turn coil 7 in order to prevent electrode displacement when assembling the electrode. I'm trying to get rid of it.

 Next, the operation of the present invention will be described.

Since the contact 1 and the electrode 2 are provided with slits, the magnetic field generated between the electrodes by the coil electrode 5 can be calculated. Next, an eddy current flowing through the one-turn coil electrode 7 is obtained. In order to obtain the eddy current flowing through the one-turn coil electrode 7, first, it is necessary to calculate the number of magnetic flux linkages between the one-turn coil electrode 7 and the magnetic field generated by the coil electrode 5, which can be calculated by the following equation.

φ (number of magnetic flux linkages) = ∫ _s Bds (1) (symbol: see FIG. 2) Further, the voltage に induced in the one-turn coil can be obtained by the following equation.

Here, FIG. 2 is an enlarged view of the one-turn coil 7, and FIG.
, S is a region surrounded by the one-turn coil 7, and A is a cross-sectional area of the one-turn coil 7. This is adopted for B and S in the equations (1) and (2).

Therefore, the eddy current i flowing through the one-turn coil electrode can be obtained by solving the following differential equation.

Here, L is the inductance of the one-turn coil 7, R
Is the resistance of the one-turn coil 7 and is determined by R = ρ × 2πr / A, and ρ is low efficiency.

As described above, since the eddy current flowing through the one-turn coil electrode 7 can be easily obtained by calculation, the magnetic field due to the eddy current flowing through the one-turn coil electrode 7 can be calculated. The actual magnetic field distribution can be obtained by superimposing this result and the calculation result of the magnetic field by the coil electrode 5. Therefore, as shown in the magnetic field distribution diagram of FIG. 4, the shape of the one-turn coil 7 is adjusted so that the conventional characteristic of A becomes a flat characteristic such as B.

〔The invention's effect〕

As described above, according to the present invention, a one-turn coil for passing an eddy current induced by a magnetic field from the coil electrode is provided on the back surface of the electrode, and the shape of the one-turn coil is adjusted so that the eddy current value and the location where the eddy current is obtained by calculation are obtained. So
The magnetic field strength distribution in the radial direction between the electrodes can be flattened, and the cutoff performance can be improved without lowering the conduction performance.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electrode portion of a vacuum valve of the present invention, FIG. 2 is an enlarged view of a one-turn coil, and FIG.
FIG. 4 is a sectional view of the magnetic field distribution between the electrodes in the radial direction. 2 ... electrode 5 ... coil electrode 7 ... one-turn coil

Claims (1)

(57) [Claims] 1. A vacuum valve having a fixed electrode and a movable electrode which are arranged inside and inside a vacuum vessel so as to be able to freely contact with and separate from each other, and a coil electrode for generating an axial magnetic field on the back of both electrodes. Is provided separately from the coil electrode on the back of
A vacuum valve comprising a one-turn coil electrode for generating a magnetic field by an induced voltage from the coil electrode and reducing a magnetic field at the center of the electrode.