JPS5916847Y2 - Magnetic field sensing transformer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transformer using a magnetic material such as a magnetic wire, which is used as a magnetic field sensor.

In a conventional transformer of this kind, as shown in FIG. 1, lead wires are drawn out directly from both ends of a magnetic wire 1 and connected to drive current supply terminals a and b.

4 is a secondary winding wound around the magnetic wire 1, and c and d are secondary winding terminals.

A polymer insulating tube 2 protects the outer periphery of the magnetic wire 1 around which the secondary winding 4 is wound, and the tertiary winding 5 is wound around the outer periphery of the polymer insulating tube.

Then, an AC power source is connected between the terminals 36, a DC bias current is passed through the tertiary winding 5, and the even harmonic output appearing at terminals c and d of the secondary winding 4 is measured (see Figure 3). ).

However, with such conventional transformers, the output waveform contains many fundamental wave components, and the signal-to-noise ratio (S/N), that is, the ratio between the signal (second harmonic) and the noise (fundamental wave) of the output waveform, is low. There was a drawback that the ratio was not very good.

The present invention is an improvement of the conventional transformer of this type in order to improve the S/N ratio, and an embodiment thereof is shown in FIG.

In FIG. 2, the same parts corresponding to FIG. 1 are given the same reference numerals.

3 is a cylindrical metal body made of copper or the like with both ends open, and the inside thereof is covered with an insulating tube 2.

A magnetic wire 1 is inserted so as to be located approximately at the central axis of the cylindrical metal body 3, and one end of the magnetic wire 1 is connected to one end of the cylindrical metal body 3 with a flexible, e.g., thin conductive wire 6. Pull out terminal a from the other end.

The terminal is pulled out from the other end of the magnetic wire 1 as before.

In this way, the magnetic wire 1 is freely maintained in the space within the cylindrical metal body 3.

As shown in FIG. 3, connecting an AC power source ep between the terminals a and l) and flowing a DC bias current to the tertiary winding 5 is the same as in the conventional case.

The magnetic wire 1 used in this example is made of copper plated with permalloy to a thickness of 1 μm, and has anisotropy in the axial direction.

Experiments have shown that in a transformer with such a configuration, the fundamental wave is suppressed and even harmonics appear in the output.

FIG. 4 shows the results of measurement using the device shown in FIG. 2 and connecting the wires as shown in FIG. 3.

In the figure, i is a drive current from an AC power source e connected to terminals a and b, and is expressed as (P-P)/2, that is, 1/2 of the peak-to-peak value.

In the figure, the bias magnetic field (A/m . . . ampere turns per meter) is used as a parameter, the dotted line shows the conventional product, and the solid line shows the case according to the present invention.

As is clear from this figure, when the drive current ip is changed, the bias magnetic field is 800 A/m even when the bias magnetic field is 60 A/m.
Even when m, the ratio S/N between the signal (second harmonic) and the noise (fundamental wave) of the output waveform is extremely better in the present invention than in the conventional one.

Furthermore, in the present invention, the magnetic wire 1 is suspended in the air so that no external force is applied to it, so the output does not decrease even after days have passed.

Although magnetic wires were used in this example, similar results can be obtained by using magnetic bodies of other shapes.

[Brief explanation of the drawing]

Figure 1 shows the configuration of a conventional magnetic field sensing transformer, Figure 2 is a partial sectional view showing the configuration of an embodiment of the present invention, Figure 3 is a wiring diagram of the magnetic field sensing transformer, and Figure 4 is a diagram of the magnetic field sensing transformer. FIG. 3 is a curve diagram showing measurement results of an example of the present invention. 1... Magnetic material, 3... Cylindrical metal body, 4
...Secondary winding, 6...Flexible conductive wire, a...Terminal connected to the other end of the magnetic body, b
・・・・・・Terminal connected to the other end of the cylindrical metal body, i,
・・・・・・Drive current.

Claims (1)

[Scope of utility model registration request] In magnetic field detection transformers using magnetic materials such as magnetic wires,
A magnetic body around which a secondary winding is wound is placed approximately at the central axis of a cylindrical metal body with both ends open, and one end of the magnetic body is connected to the cylindrical metal body using a flexible conductive wire. By connecting one end of the magnetic body and the other end of the magnetic body to a terminal, the magnetic body can be maintained freely in space, and the terminal connected to the other end of the magnetic body and the other end of the cylindrical metal body can be connected to the other end of the magnetic body. A transformer for detecting a magnetic field, characterized in that a drive current is supplied from a terminal connected to one end of the transformer.