JPS6170468A - Current detector - Google Patents

Abstract

PURPOSE:To insert a conductor to be measured into an iron core magnetic circuit simply and to reduce an error by forming a driving device for driving a movable iron core arranged close to a gap in which a magnetic optical part is set up. CONSTITUTION:The titled device is provided with an iron core 1, a fixed iron core 1a, a movable iron core 1b, a driving device 7, a gap 11, etc. When a compression spring 7a in the device 7 is compressed, the leading end of the movable iron core 1b is opened from the fixed iron core 1a and a conductor 6 is passed through the opened part and inserted into the iron core 1. When the compression of the spring 7 is released, the movable iron core 1b is rotated in the clockwise direction by the device 7 and joined with the fixed iron core 1a. At the measurement of current flowing into the conductor 6, the conductor 6 arranged adjacently to the gap 11 is separated from the gap 11 because of the existence of a case 8 and a magnetic field formed on the gap 11 by the conductor 6 is weakened, so that an error is reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a current detection device that detects the magnitude of a magnetic field created by a current using a magneto-optical element, converts it into a current value, and measures the current. .

[Prior Art] FIG. 1 shows a conventional through-type photocurrent detection device. In the figure (11 has a partial gap Qη).

The iron core that constitutes the magnetic closed circuit, (2) is the gap IJjJ
The magneto-optical section installed in It consists of an analyzer whose intensity changes.

(3) is the fixing agent that fixes the iron core (υ) and the magneto-optical section (2), (4) is the optical fiber cable (5) that connects the magneto-optical section (2) and the converter (5) is the optical transceiver.

A conversion device consisting of a light intensity-to-electrical converter and an indicator (
6) are the conductors (a) and (b) through which the current to be measured flows.
, (cl.

(d) is a current-carrying conductor located near the outside of the magnetic closed circuit.

A conventional photocurrent meter is constructed as described above, with a conductor (6]f
The flowing current generates a magnetic field in the y direction shown in Figure @1 in the magneto-optical section installed in the gap Oυ of the iron core (υ). The light intensity changes in the magneto-optical section (2) in proportion to the magnitude of the magnetic field.

Fiber optic cable (returned by 4j), conversion device (5
) performs light intensity-to-electricity conversion and displays the current value on a display.

However, in the conventional type, current-carrying conductors (a), (b), (c), and (d) can easily be located near the outside of the iron core (υ).Such current-carrying conductors (a),
The state of the magnetic flux (φ) with respect to the gap aυ of the iron core (1) when (b), (c), and (d) exist is @1
It is shown in Figure-1, Figure 1-2, and Figure 1-i11. This magnetic flux (fl) results in an error in the magnitude of the magnetic field in the gap ση created by the current in the conductor (6). Figure @2 shows the position and error (ε) characteristics of current-carrying conductors (a), (b), (c), and (d).When the current-carrying conductor is (a)
, In the case of (C), the current-carrying conductor (
The magnetic field in the y direction created by a) and (c) is weak, and the error (ε
) is also small, but when the current-carrying conductor is (d), the gap αυ
Since there is some leakage magnetic flux (-) passing through the gap ση, the magnetic field in the y direction is a little stronger at the gap ση, and the error (ε) is slightly larger. When the current-carrying conductor is (b), the magnetic flux in the y direction becomes even stronger, causing the maximum error [ε], and this error (ε) becomes a particular problem. The four points have been described above, but the error (ε) for other adjacent current-carrying conductors is plotted phenomenologically as shown in Figure 2.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional current detection device, when there is a current-carrying conductor (6) near the gap (B) outside the magnetic closed circuit, there is an error (
There was a problem in that ε) occurred, which interfered with measurement.

This invention was made to solve this problem, and even if there is a current-carrying conductor near the gap outside the magnetic closed circuit, the error in the current measurement value of the conductor through which the current to be measured flows is a problem. The aim is to obtain a device whose size can be kept to a level where it will not become large.

[Means for solving problems]

The current detection device according to the present invention is composed of a movable core and a fixed core that form a magnetic closed circuit, and is arranged near the core having a gap and the gap.

A drive device for driving the movable iron core and a case for mounting this drive device are installed near the gap.

(Function) In this invention, since there is a case near the gap, a current-carrying conductor near the outside of the magnetic closed circuit cannot approach the gap, and this current-carrying conductor is affected by the strength of the magnetic field generated in the gap. The error in the measurement current of the measurement conductor is suppressed so that it does not become a problem.

〔Example〕

FIG. 3 is a front view showing one embodiment of the present invention, in which (1) is an iron core that constitutes a magnetic closed circuit, and (la) is a fixed iron core.

(1b) is a movable iron core. ση is a gap provided in a part of the iron core (1), and although it is provided in the fixed iron core (1a) in the figure, it may be provided in the movable iron core (1b). (2
) is the magneto-optical section installed in the gap (b), (3) is the fixing agent 1 (4) that fixes the iron core (υ and the magneto-optical section 12)
is an optical fiber cable connecting the magneto-optical section (2) and the converter (5), (6) is a conductor through which the DC to be measured flows, (
7) is arranged near the gap aυ, and the movable iron core (1b
), (7a) is a compression spring constituting a part of the drive device, and (8) is a current-carrying conductor (a), (b) to which the drive device (7) is attached and which is close to the outside of the magnetic closed circuit.
), (c), and (d) are prevented from approaching the gap aυ.

In operation, when the compression spring (7a) of the drive device (7) is compressed, the tip of the movable core (1b) opens from the tip of the fixed core (1a), and the conductor (6) passes through and enters the core (1). come. Then, when the compression spring (7a) is released, the drive device (
7) works to move the movable iron core (1b) connected to the drive device (7).
) rotates clockwise and joins with the fixed iron core (1a).

There, the current in the conductor (6) is measured, but because of the case (8), the current-carrying conductor (6), which was close to the gap αυ, is measured.
) is moved away from the vicinity of the gap, and the magnetic field created by the current-carrying conductor (6) in the gear becomes weaker, so that the error (ε) is reduced to a value that does not pose a problem. Figure 4 is a characteristic diagram showing this situation. The error (ε) due to the current-carrying conductor (a) and ((to) is the same as before, but the error (ε) due to the current-carrying conductor (b) is It can be seen that it has become significantly smaller.

(Effects of the Invention) As described above, the present invention provides a driving device for driving a movable core placed near the gap in which the magneto-optical section is installed, thereby easily moving the current conductor to be measured into the core magnetic closed circuit. Not only can this drive device be installed in a case that prevents current-carrying conductors near the outside of the magnetic closed circuit from approaching the gap, it has the effect of reducing errors. .

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional current detection device, Figures 1-1 to 1-3 are diagrams showing the position of the current-carrying conductor and magnetic flux distribution, and Figure 2 is a diagram showing the position of the current-carrying conductor and the measurement current. 3 is a front view showing an embodiment of the present invention, and 4 is a diagram showing the relationship between errors.
The figure is a diagram showing the relationship between the position of the current-carrying conductor and the error in the measured current. In the figure, (1) is the iron core, (1a) is the fixed iron core, (
lb) is the movable core 1 port is the gap, (2] is the optical part, (5) is the conversion device, (6I is the conductor, (7) is the drive device, (8) is the case, '(a), ( b), Cc
) and (d) are current-carrying conductors. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] The core is composed of a movable core and a fixed core that form a magnetic closed circuit, and has a gap, and the current flowing through the conductor passing through the core converts the magnitude of the magnetic field created in the gap into the intensity of light. Magneto-optical section provided,
A conversion device that converts the intensity of light converted by the magneto-optical section into the magnitude of current, a drive device that is disposed near the gap and drives the movable core, and a magnetic closed circuit to which this drive device is attached. A current detection device comprising a case that prevents a current-carrying conductor near the outside of the device from approaching the gap.