JPS613068A - Current sensor using magnetic fluid - Google Patents

Abstract

PURPOSE:To obtain an inexpensive current sensor with a simple construction, by using a magnetic fluid. CONSTITUTION:A container 10 made of a insulator surrounding a wire 18 is provided and electrodes 20 and 21 are provided at the position near the wire in a container as insulated from the wire 18. Moreover, an insulating magnetic fluid 12 and a conductive liquid are put in the container 18. When no current flows through the wire 18, the electrodes 20 and 21 are short-circuited by the liquid 16 while when it does, at least one of the electrodes 20 and 21 is allowed to be covered with the magnetic fluid 12 creeping up the surface of the wire 18 or the internal surface of the container 10. It should be noted that some magnetic fluids have a conductivity through water or the like as dispersion medium. When the magnetic fluid with a conductivity of this type is used, the magnetic fluid 22 shall be placed in the container 10 beforehand so that the short-circuiting will be caused between the electrodes 20 and 21 with the magnetic fluid 22 creeping up the surface of the wire 18 or the internal surface of the container 10 when current flows through the wire 18.

Description

DETAILED DESCRIPTION OF THE INVENTION For example, it is used to detect whether or not current is flowing through a DC cable at a rising portion of a cable or inside a manhole. In addition to this, it can also be used particularly for detecting large currents.

The magnetic core of the stirrup rice plant is used to detect induced voltage through magnetic flux.

To provide a current sensor with a simpler structure and lower price than conventional ones by using a free magnetic fluid.

Inserted Matasato Yu is destroyed This application consists of two inventions.

The first invention is as follows.

As shown in FIG. 9, put the magnetic fluid 12 into the container lO,
It is known that when a metal rod 14 is placed upright in it and a current is passed through it, the magnetic fluid 12 moves along the metal rod 14.

Many magnetic fluids have insulating properties (for example, those using synthetic oil as a dispersion medium), so the first invention uses an insulating magnetic fluid and utilizes the above phenomenon.

As shown in Fig. fJSl1 and Fig. 12, (1) a container lO made of an insulator is provided surrounding the electric wire 18, and a pair of electrodes 20 and 21 are placed near the electric wire in the container. (2) Also, an insulating magnetic fluid 12 and a conductive liquid 16 are placed in the container 10, and when no current is flowing through the wire, the liquid 16 closes the electrode. 20.21 should be short-circuited (for example, by turning on the lamp 19); (3) When current flows through Min, 18, the electrodes should be 20. Made sure that at least one side of 21 is covered (
The gap between the electrodes is electrically turned off (open state 8) and the lamp 19 goes out.

It is characterized by

Some magnetic fluids have conductivity using water or the like as a dispersion medium. Using a magnetic fluid with such conductivity makes the structure simpler.

The second invention utilizes this.

As shown in FIGS. 13 and 14, (1) electric wire 18
(2) A container 10 made of an insulator is provided surrounding the electric wire, and a pair of electrodes 20 and 21 are provided in the container at a position close to the electric wire insulated from the electric wire. (3) When a current flows through the electric wire, the electrodes are short-circuited by the magnetic fluid that flows through the surface of the electric wire or the inner surface of the container. do.

Example 1 (Figs. 1 and 2) 10 is the entire container, for example, an inner cylinder 20 and an outer cylinder 21, which also serve as electrodes, are arranged coaxially, and insulating plates 24, 26 are placed above and below the inner cylinder 20 and outer cylinder 21.
It is something that has been attached to it.

An insulating magnetic fluid 12 and a conductive liquid 16 (for example, water) are placed in a container 10 .

The electric current mia is made to penetrate the inside of the inner electrode 20 below -L.

When no current is flowing through the wire 18, the electrodes 20 and 21 are short-circuited by the conductive liquid 16, as shown in the fiS1 diagram.
Therefore, for example, the lamp 19 is on.

When a current flows through the wire 18, the magnetic fluid 12 crawls up the inner tube and finally covers the entire surface of the electrode 20, as shown in FIG.

Then, since the magnetic fluid 12 is insulating, the magnetic fluid 12 electrically turns OFF between the electrodes 20 and 21.
The state becomes 1ri (open state).

Note that the larger the current, the higher the height of the magnetic fluid 12. Therefore, if the height a of the electrode 20 is set appropriately and the magnetic fluid 12 covers the entire surface of the electrode 20 when the set operating current value 1c flows, it will not operate below Ic, but above Ic. It becomes a sensor that works when it gets old.

Length 1” (Figure 3, 'ft54) Inner cylinder 28 of container 10. Both the outer cylinder 30 are made of an insulator.

Then, for example, the ring-shaped electrodes i20, 21 are inserted into the inner cylinder 28.
Attach it to the F part and the upper part of.

Figure 3 shows a state where no current is flowing! On the island, electrode 20.2
1 is short-circuited by a conductive liquid 16.

When a current flows through the wire 18, the magnetic fluid 1 flows as shown in FIG.
2 covers the electrode 20. Then, similarly to the above, the electrodes 20 and 21 are electrically turned off (open).

In this case, by changing the mounting height b of the lower electrode 20, the set operating current value 1c can be changed.

This type of device can also be used tilted as shown in FIGS. 5 and 6. Since the operation in this case is the same as above, the explanation will be omitted.

``Inudenmawari'' (Figure 7, Figure N48) A four-electric ff1f'l fluid 22 and an insulating liquid or gas 32 (air may be used) are used.

The structure of the container 10 and the arrangement of the electrodes 20.21 are the same as in Example 2.

In this case, it can be used horizontally.

Figure 7 shows electrodes 20.21 and 20.21 with no current flowing.
The period between the two is in an electrically OFF state (open state).

When a current flows, the magnetic fluid 22 moves toward the electric wire 18 as shown in Figure 8 (the closer the electric wire 18 is, the stronger the magnetic field becomes).
The inner surface of the container 10 is pushed into contact with the electrodes 20.21. Then, since the magnetic fluid 22 is electrically conductive, the electrodes 20 and 21 are short-circuited.

In this case, the set operating current value 1c can be changed by changing the mounting height C of the electrodes 20.21.

＆艮しε moxibustion (+) The structure is simple, compact, and has long-term stability.

(2) Ferrofluid and container - It is cheap because it can be made of electric wire and wood.

(3) If you measure the height of a magnetic fluid, it can also be used as an ammeter.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of the first embodiment, with FIG. 1 showing a non-energized state and FIG. 2 showing a energized state. 3 to 16 are explanatory diagrams of the second embodiment, in which FIGS. 3 and 5 show a non-energized state, and FIGS. 4 and 6 show a energized state. MS7 and FIG. 8 are explanatory diagrams of the third embodiment, where FIG. 7 shows a non-energized state and FIG. 8 shows a energized state. Fig. 9 and Fig. 10 of the container are explanatory diagrams of the principle, Fig. 11 and Fig. 12 of the magnetic fluid are explanatory diagrams of the first invention, Fig. 13 and piS1
FIG. 4 is an explanatory diagram of the second invention.

Claims (2)

[Claims] (1) Set up a container made of insulator to surround the electric wire,
A pair of electrodes is installed in the container at a position close to the wire, insulated from the wire, and an insulating magnetic fluid and a conductive liquid are placed in the container so that a current flows through the wire. When the conductive liquid is not used, the electrodes are short-circuited by the conductive liquid, and when a current flows through the wire, at least one of the electrodes is covered by the magnetic fluid that crawls up the surface of the wire or the inner surface of the container. A current sensor using a magnetic fluid, characterized in that the magnetic fluid is (2) Provide a container made of insulator to surround the electric wire,
A pair of electrodes is installed in the container at a position close to the wire, insulated from the wire, and a conductive magnetic fluid is placed in the container. A current sensor using a magnetic fluid, characterized in that the electrodes are short-circuited by the magnetic fluid creeping up the inner surface of the electrode.