JP2000199770A - Low-noise multicore parallel-cord current detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-noise multicore parallel-cord current detector with which a current flowing in a parallel cord can be detected safely and simply, in a state in which an electromagnetic inducted noise at the outside is reduced by a method wherein a noise signal from the outside is guided to a cylindrical magnetic body in which a coil having a magnetic core is provided. SOLUTION: In this current detector, a parallel cord 1 is sandwiched between a half 21 and a half 22 of a cylindrical magnetic body 13, which is provided with a coil 8 having a magnetic core. Then, when a current a2 and a current b3 flow into the parallel cord 1, lines of magnetic force are passed through the core in the current of the cylindrical magnetic body 13, an electromotive force is generated in the coil 8, and an electric signal is obtained. At this time, lines of magnetic force from the outside, which becomes a noise reach the coil 8 and influences the electrical signal as noise. However, by making the lines of magnetic force from the outside to be guided to the cylindrical magnetic body 13, it made hard to reach the coil 8, and the noise can be reduced. Thereby, without cutting signal lines, the electrifying state of an electrical apparatus and the strength of a signal can be detected simply.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current detector provided with a structure for reducing the influence of electromagnetic induction noise, such as a power supply parallel cord and a speaker parallel cord typified by a flat two-core parallel cord of electric equipment. The present invention relates to a magnetic detector, that is, a current detector, which can easily detect the energized state of an electric device and the strength of a signal without disconnecting the signal line.

[0002]

2. Description of the Related Art A portion of a current flowing through a parallel cord, which does not cancel out a magnetic flux generated by the current, that is, a magnetic flux generated between conductors of the parallel cord, is EI or EE.
A magnetic detector such as a ferrite core or an iron core made of a magnetic material such as a core and a coil, a Hall element, or a magnetic detector of a magnetoresistive element or the like detects the current using a magnetic detector of a parallel cord, that is, a current detector.

[0003]

As described above, a magnetic detector using an EI or EE core, which has been widely used, is easy to manufacture, but the detection signal 18 is used as an actual measurement example in the parallel code. When a current of 1 A is flowing, it is as small as several millivolts, and when there is a device that is easily affected by external magnetic lines of force and generates strong magnetism nearby, such as a transformer or a motor, accurate current detection cannot be performed due to electromagnetic induction noise. there is a possibility. In the case of a multi-core cord, a plurality of parallel cord current detectors are required.

[0004]

SUMMARY OF THE INVENTION A low-noise parallel code current detector according to the present invention has been described with reference to FIG.
(A) Instead of the conventional EI or EE core as shown in (B), a coil having a magnetic core in the cylindrical magnetic body shown in FIGS. Induction and noise signals from the magnetic head are guided to the cylindrical magnetic body, so that magnetic lines of force that make noise hardly reach the detection element.

[0005] The cylindrical magnetic body is shown in FIG.
As shown in (B), the parallel cord can be sandwiched by being divided into a half a21 of the cylindrical magnetic body and a half b22 of the cylindrical magnetic body. It is also conceivable to divide by a ratio for obtaining a necessary signal between lines as shown in FIG. By covering the outer surface of the cylindrical magnetic body with a metal such as a copper foil, that is, a conductor, and grounding 12, it is possible to further reduce electromagnetic noise and electrostatic noise. Furthermore, for insulation and exterior, it is covered with a container 19 made of synthetic resin or the like, and the container couples the cylindrical magnetic bodies a and b without any gap. When the mark 26 of the parallel cord is aligned with the mark 25 of the cushion 20, the multi-core parallel cord can be fixed at a correct position with respect to the magnetic detector.

[0006]

As shown in FIGS. 1A and 1B, when the parallel cord 1 is sandwiched between a half a22 of the cylindrical magnetic body and a half b23 of the cylindrical magnetic body, a current a2 flowing through the parallel cord is obtained. Due to the current b3, lines of magnetic force a4 and lines of magnetic force b5 are generated around the conductor of the parallel cord by the right-hand rule, but the lines of magnetic force cancel each other around the parallel cord. As shown in FIG. 3, the parallel cord is sandwiched between the E-shaped magnetic body 6 and the E-shaped magnetic body 7 to form a magnetic circuit, and the magnetic lines of force 4 and 5 passing between the insulating coverings of the parallel cord are formed by the E-shaped magnetic body. It is passed through the core at the center of the shaped magnetic body 6 and detected by the coil 8 in the case of AC only, and by the element incorporating the Hall element or the magnetoresistive element 9 shown in FIG. 1C in the case of AC or DC. FIG.
(A) and (B) are principle diagrams of the magnetic detector important to the present invention, in which a line of magnetic force passes through the core at the center of the E-shaped magnetic body to generate an electromotive force in the coil 8, that is, to obtain an electric signal. However, as shown in FIGS. 3A and 3B, the magnetic field lines 10 that become noise from the outside reach the detection element and affect the electric signal 18 as noise. In the case of the present invention, however, FIG. A)
As shown in (B), the external magnetic field lines 10 are guided to the cylindrical magnetic body 13 so that noise can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the sectional views of FIGS. 5 (A), 5 (B), 5 (C), and 5 (C) ', a low noise multicore parallel cord current tester of the present invention is mounted on various parallel cords. This is an example in which a current is inspected. The various cords are conductors such as a 2-core parallel cord, a 3-core parallel cord, and a 4-core parallel cord, and are covered with insulating material such as vinyl, rubber, etc.
They are for three-phase power, for information signals, and for audio signals. Modifications such as shape and dimensions to fit various codes,
It is intended to be included in the scope of the present invention.

FIG. 6 shows that a signal obtained from the parallel-code current detector is a computer system 16 having an amplifier 15 including a differential amplifier, an integrator, a linearity corrector, a rectifier, an AD converter 23, and a hard disk 24. This is an example in which the current is monitored by using.

[0009]

As described above in detail, according to the present invention, the electrical equipment is electrically insulated in various environments in a state where the external electromagnetic induction noise is reduced and the electrical equipment is used without any change. In this state, the current flowing through the parallel cord can be detected safely and easily, the energization state can be easily confirmed, and the state of the electric signal line between the devices, that is, the operation of the devices, can be monitored. Since it is possible, it is possible to contribute to improvement of safety management and energy saving and operation management of equipment.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a conventional parallel cord current detector.

FIG. 2 is a configuration diagram 1 according to an embodiment of the present invention.

FIG. 3 Disadvantages of a conventional detector

FIG. 4 shows the principle of the detector of the present invention.

FIG. 5 is a configuration diagram 2 according to an embodiment of the present invention.

FIG. 5 is a configuration diagram 3 according to an embodiment of the present invention.

FIG. 6 is a configuration diagram 4 according to an embodiment of the present invention.

[Explanation of symbols]

Parallel cord 1, current a2 flowing through the cord, current b3 flowing through the cord, magnetic field line a4, magnetic field line b5, E-shaped magnetic body 6,
E-type magnetic body 7, coil 8, Hall element or magnetoresistive element 9, line of magnetic force from outside 10, copper foil 11, ground 12, cylindrical magnetic body 13, low noise multicore parallel cord current detector 1
4, amplifier 15, computer system 16, magnetic detector 17, detection signal 18, container 19, cushion 20, half of cylindrical magnetic body a21, half of cylindrical magnetic body b22,
AD converter 23, hard disk 24, cushion mark 25, parallel code mark 26

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[Procedure amendment]

[Submission date] April 15, 1999 (1999.4.1
5)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a principle diagram of a conventional parallel cord current detector.

FIG. 2 is a configuration diagram 1 according to an embodiment of the present invention.

FIG. 3 Disadvantages of a conventional detector

FIG. 4 shows the principle of the detector of the present invention.

FIG. 5 is a configuration diagram 2 according to an embodiment of the present invention.

FIG. 6 is a configuration diagram 3 according to an embodiment of the present invention.

[Description of Signs] Parallel cord 1, current a2 flowing through the cord, current b3 flowing through the cord, magnetic field line a4, magnetic field line b5, E-type magnetic body 6,
E-type magnetic body 7, coil 8, Hall element or magnetoresistive element 9, line of magnetic force from outside 10, copper foil 11, ground 12, cylindrical magnetic body 13, low noise multicore parallel cord current detector 1
4, amplifier 15, computer system 16, magnetic detector 17, detection signal 18, container 19, cushion 20, half of cylindrical magnetic body a21, half of cylindrical magnetic body b22,
AD converter 23, hard disk 24, cushion mark 25, parallel code mark 26

Claims (1)

[Claims] An electric current flowing through a parallel cord, a portion of a magnetic field generated by the current which does not cancel each other, that is, a magnetic line generated between conductors of the parallel cord, a magnetic material such as a ferrite core or an iron core, a coil or a Hall element. Or a multi-core parallel cord with a parallel cord magnetic detector consisting of a magnetoresistive element, surrounded by a cushion that can be divided in the long axis direction, a cylindrical magnetic body, and a metal shield to simplify handling such as alignment and reduce electromagnetic induction noise Current detector.