JPH10282157A - Optical fiber current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber current sensor that can pass through even an established electric circuit and can be mounted easily. SOLUTION: In an optical fiber current sensor where an electric path 8 passes through a hole 2 of a folder 1 being formed in doughnut shape, at the same time, an optical fiber 5 that has a polarizer 6 and an analyzer 7 at both ends is fixed to an outer periphery surface of the folder 1, and a current flowing in the electric path 8 is detected by utilizing Faraday effect, the folder 1 is divided into a member 1a and a member 1b, one end is interlocked by a joint part 3 so that the other end can be opened and closed, and the polarizer 6 and the analyzer 7 are fixed to the switchable end of the folder 1 and at the same time are arranged so that they oppose each other when the folder 1 is in closed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber current sensor for detecting a current flowing in an electric circuit such as a transmission line using an optical fiber having a Faraday effect.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a conventional optical fiber current sensor. This optical fiber current sensor passes an electric path 18 through a hole 12 of a donut-shaped folder 11,
An optical fiber 15 is fixed on the outer peripheral surface of the folder 11, and a polarizer 16 and an analyzer 17 are provided at both ends of the optical fiber 15.

[0003] When a current flows through the electric circuit 18, a magnetic field is generated in the longitudinal direction of the optical fiber 15 around the electric circuit 18. When a light emitting unit (not shown) is connected to one end of the optical fiber 15 via a polarizer 16 and polarized light (linearly polarized light) is incident on the optical fiber 15, the optical fiber 15 has a Faraday effect. The plane of polarization rotates at a rotation angle proportional to the intensity. When a light receiving unit (not shown) is connected to the other end of the optical fiber 15 via an analyzer 17 and the light whose polarization plane is rotated is incident on the analyzer 17, light having an intensity proportional to the rotation angle of the polarization plane is obtained. Are emitted and received by the light receiving section. Since the intensity of the magnetic field is proportional to the magnitude of the current, the light having the intensity proportional to the magnitude of the current can be received by the light receiving unit, so that the magnitude of the current in the electric circuit 18 can be detected.

[0004]

However, this conventional optical fiber current sensor has a hole 12 in a folder 11.
However, since the folder 11 has a donut shape, it is necessary to mount the optical fiber current sensor before installing the electric line 18, and application to existing equipment is not easy. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical fiber current sensor which can be easily attached to an existing electric circuit by penetrating the electric circuit.

[0006]

According to the present invention, an electric path is passed through a hole of a donut-shaped folder, and an optical fiber having a polarizer and an analyzer at both ends is fixed on the outer peripheral surface of the folder. In the optical fiber current sensor for detecting a current flowing through the electric circuit using the Faraday effect, the folder is divided into two, and one end thereof can be opened and closed, and the other end is connected by a joint, The polarizer and the analyzer are fixed to an openable and closable end of the folder, and are arranged to face each other when the folder is in a closed state.

In the optical fiber current sensor according to the present invention, one end of the folder is opened by the joint,
In this state, the electric circuit may be penetrated through the hole of the folder, so that the existing electric circuit can be easily attached without removing the existing electric circuit.

[0008]

FIG. 1 shows an example of an embodiment of the present invention.
This will be described below. FIG. 1A shows a state after attachment. FIG. 1B shows a front view after attachment. FIG.
(C) shows a top view before mounting.

In these figures, a folder 1 is a member 1
a and a member 1b, and the other end is connected by a joint 3 such as a hinge or a pin so that one end can be opened and closed. An optical fiber 5 having a polarizer 6 and an analyzer 7 at both ends is fixed on the outer peripheral surface of the folder 1. In this case, the polarizer 6 and the analyzer 7 are located at the openable and closable end of the folder 1, the polarizer 6 is fixed to the member 1a, the analyzer 7 is fixed to the member 1b, and the folder 1 is closed. When in the state,
They are arranged to face each other. The mounting seat 4 is for mounting the folder 1.

When an optical fiber current sensor is mounted on the electric circuit 8 when the electric circuit 8 is already installed, one end of the folder 1 is opened by the joint 3 as shown in FIG. It is arranged so as to penetrate one hole 2. Next, as shown in FIG. 1A, the folder 1 is closed, and the folder 1 is fixed to the device using the mounting seat 4. Thus, as shown in FIG. 1B, the optical fiber 5 is fixed to the outer periphery of the folder 1, and the polarizer 6 and the analyzer 7 are arranged to face each other.

In this optical fiber current sensor, when a current flows through the electric circuit 8, a magnetic field is generated in the longitudinal direction of the optical fiber 5 around the electric circuit 8. When the linearly polarized light passing through the polarizer 6 enters the optical fiber 5, the plane of polarization is rotated by a Faraday effect of the optical fiber 5 to a rotation angle proportional to the strength of the magnetic field, and is emitted to the analyzer 7. By detecting the light intensity with the analyzer 7, the magnitude of the current flowing through the electric circuit 8 can be detected.

[0012]

According to the optical fiber current sensor of the present invention, since one end of the folder is opened and closed by the joint, it can be easily mounted on the existing electric circuit. Also, since the polarizer, analyzer and optical fiber are fixed to the folder, they are less affected by vibration and the like, and if one end of the folder is closed, the polarizer and analyzer will face each other. The optical fiber current sensor can be mounted in a short time.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of an optical fiber current sensor according to the present invention, in which (A) is a perspective view after installation, and (B).
Is a front view after mounting, and (C) is a top view at the time of mounting.

FIG. 2 is a perspective view showing an example of a conventional optical fiber current sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Folder 2 Hole part 3 Joint part 4 Mounting seat 5 Optical fiber 6 Polarizer 7 Analyzer 8 Electric circuit

Claims (1)

[Claims] An electric circuit having a hole formed in a donut-shaped folder is made to penetrate an electric circuit, an optical fiber having a polarizer and an analyzer at both ends is fixed on an outer peripheral surface of the folder, and a current flowing through the electric circuit is reduced. In the optical fiber current sensor that detects using the Faraday effect, the folder is divided into two, and one end thereof is openable and closable, and the other end is connected by a joint portion. The polarizer and the analyzer are An optical fiber current sensor fixed to one end of a folder which can be opened and closed, and arranged to face each other when the folder is closed.