JPH0787152B2 - Noise prevention transformer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a noise prevention transformer provided with a noise prevention measure.

[Prior Art] Conventionally, this type of noise prevention transformer uses a conductive wire in which a conductive wire is covered with a resin insulator as the primary winding and the secondary winding, and prevents the propagation of the following noise. Various measures have been taken to protect it.

There are the following three main causes of noise propagation.

Propagate through the capacitance between the primary and secondary windings.

Due to the electromagnetic induction action, noise in the high frequency band mainly propagates from the primary winding to the secondary winding.

Magnetic field lines due to noise pass through the air and generate an induced electromotive force in the secondary winding.

In the conventional transformer, in order to prevent the propagation of noise due to such a cause, a conductive seal material shields between the primary winding and the secondary winding.

In order to prevent the propagation of noise due to the above causes, for example, as shown in FIG.
The grounded conductive electrostatic shield material 1 was inserted between the secondary winding S and the secondary winding S. The electrostatic shield material 1 reduces the electrostatic capacitance between the primary winding P and the secondary winding S, and reduces the noise propagating to the secondary winding S through the electrostatic capacitance.

Further, in order to prevent the propagation of noise due to the above causes, as shown in FIGS. 8 and 9, for example, the primary winding P
The outer periphery of (or the secondary winding S) was covered with the conductive shielding material 2. In the figure, 3 is a conductor of the primary winding P (or the secondary winding S), 4 is an insulating coating made of resin, and 5 is an iron core. Now, when a current is applied to the primary winding P in the direction of arrow A (see FIG. 9), this current causes a magnetic force line a (see FIG. 8).
Occurs. A reverse current in the direction of arrow B flows through the conductive shield material 2 located in the magnetic force line a. As a result,
On the surface of the conductive shield material 2, magnetic force lines b in the opposite direction that cancel the magnetic force lines a by the primary winding P are generated, and the magnetic force does not go out. As a result, the magnetic lines of force generated by the noise of the primary winding P are confined on the surface of the primary winding P and do not reach the secondary winding S, preventing the propagation of noise to the secondary winding S due to electromagnetic coupling. Get off.

Further, in order to prevent the propagation of noise due to the above causes, the outer circumference of the primary winding P or the secondary winding S is covered with a magnetic material. This magnetic material prevents the leakage of magnetic force to the outside by passing magnetic lines of force through the inside. As a result, the leakage magnetic flux from the primary winding P is absorbed to prevent the magnetic flux from interlinking with the secondary winding S, thus preventing the propagation of noise.

In this way, the conventional transformer, apart from the winding and the iron core,
By providing a conductive shielding material and a magnetic material, it has been configured to prevent the propagation of noise.

[Problems to be Solved by the Invention] However, the above-described conventional transformer has the following problems.

That is, in order to prevent the propagation of noise, a conductive shielding material and a magnetic material are provided in addition to the winding wire and the iron core, so that it is inevitably necessary to secure a space for containing those materials. However, there is a problem that the whole transformer becomes large, the structure becomes complicated, and the price becomes high. Moreover, the effect is small unless the propagation of noise due to the above causes is prevented at the same time.

The present invention aims to solve such a problem.

[Means for Solving the Problems] A noise prevention transformer according to the present invention is an electric wire in which an outer circumference of a conductor wire insulation-coated with an insulating material is covered with a magnetic material having a resistivity lower than that of the insulating material.
In the noise prevention transformer used for the primary winding and the secondary winding respectively, the magnetic material is closely adhered to the entire surface of this insulated wire, and the magnetic materials of the primary winding and the secondary winding are respectively attached. It is characterized by being grounded.

[Operation] In the noise prevention transformer of the present invention, by using as the winding wire, an electric wire in which the outer circumference of a conductive wire which is insulation-coated with an insulating material is covered with a magnetic material having a resistivity lower than that of the insulating material, Depending on the winding itself,
At the same time, prevent noise propagation due to.

As a result, it is not necessary to provide a special conductive shielding material or magnetic material as in the related art, and the entire transformer can be downsized, the structure can be simplified, and the cost can be reduced.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 6. The same parts as those in the conventional example described above are designated by the same reference numerals and the description thereof will be omitted.

1 to 4 are views for explaining the first embodiment of the present invention.

In this embodiment, as the primary winding P and the secondary winding S,
The outer circumference of the insulating coating 4 covering the conductor 3 is covered with the insulating coating 4
An electric wire covered with a magnetic material 6 having a lower resistivity than that is used. By winding the primary winding P and the secondary winding S, the respective magnetic materials 6 are in close contact with each other, and the respective magnetic materials are grounded as shown in FIG. The resistivity of the insulating coating 4 is such that the secondary induced electromotive force generated on the surface of the windings P and S is small when a predetermined current as a transformer is applied to the windings P and S. The resistivity is high enough that the heat generated by electric power does not affect the performance of the transformer.

The magnetic material 6 covering the windings P and S has the above-mentioned ,,
The propagation of noise due to the three causes is simultaneously prevented as follows.

"Prevention of noise propagation due to cause" Since the magnetic material 6 in the windings P and S is closely grounded in each winding P and S, the electrostatic capacitance between the windings P and S is extremely small. Become.

Further, when an electric current is passed through the primary winding P, an electric charge (for example, “−”) having a polarity opposite to the electric charge (for example, “+”) appearing in the conductor 3 is applied to the magnetic material 6 on the surface of the winding P. Appear, and because this magnetic material 6 is grounded, the magnetic material 6
The lines of electric force due to the electric charges appearing at the point of disappearing toward the ground as indicated by the arrow in FIG. By the way, when the primary winding P is not covered with the magnetic material 6, the “−” pole is located at infinity and the line of electric force extends far, and in particular, it is induced in the secondary winding S through capacitance. An electromotive force will be generated.

After all, although the magnetic material 6 has a high resistivity, it has a low electrostatic resistance, has a sufficient electrostatic shielding effect, and reliably prevents noise propagating through the electrostatic capacitance.

"Prevention of noise propagation due to cause" Since the magnetic materials 6 in the windings P and S are in close contact with each other in the windings P and S, the outer circumferences of the windings P and S are surrounded by the magnetic material 6. Become. Therefore, the above-mentioned eighth
As in the case of FIG. 9 and FIG. 9, when a current is passed through the primary winding P, a magnetic force line b in the direction opposite to the magnetic force line a due to the winding is generated on the surface of the magnetic material 6 as shown in FIG. , Magnetic force does not come out. This prevents noise propagation due to electromagnetic coupling.

"Prevention of noise propagation due to cause" Since the magnetic materials 6 in the windings P and S are in close contact with each other in the windings P and S, the outer circumferences of the windings P and S are surrounded by the magnetic material 6. Become. The magnetic force lines pass through the magnetic material 6 having a small magnetic resistance and prevent leakage to the outside. Therefore,
The magnetic flux leaking from the primary winding P is absorbed by the magnetic material 6 as shown in FIG. 4, so that it is prevented from interlinking with the secondary winding S and the propagation of noise is prevented.

As described above, the magnetic material 6 covering the windings P and S simultaneously prevents the noise propagation due to the above-mentioned causes.

FIG. 5 and FIG. 6 show that the primary winding P and the secondary winding S are formed by winding an electric insulating tape having two layers of the insulating coating 4 and the magnetic material 6 on the outer circumference of the conductor 3. ing. Note that an electrically insulating tape containing a magnetic material may be used instead of the insulating coating 4 and the magnetic material 6 having two layers.

In addition to using the wires covered with the magnetic material 6 as the windings P and S, the entire primary winding P and the secondary winding S may be covered with a conductor or a magnetic material, respectively.

Further, the electric wire covered with the magnetic material 6 can be widely used in addition to the windings P and S as an electric wire in which leakage magnetic flux does not go out.

[Effect] As described above, according to the noise prevention transformer of the present invention, the magnetic material is closely adhered to the entire surface of the insulating coated conductor, and the magnetic materials of the primary winding and the secondary winding are grounded. Therefore, the winding itself can simultaneously prevent the noise propagation due to the above-mentioned causes. Therefore, it is not necessary to provide a special conductive shielding material or magnetic material as in the conventional case, and accordingly, the size reduction of the entire transformer, the simplification of the structure, and the cost reduction can be realized. In particular, since there is no room for electrostatic capacitance between the winding and the magnetic body, the electrostatic shield effect can be greatly improved.

[Brief description of drawings]

1 to 6 are views for explaining an embodiment of the present invention, wherein FIG. 1 is a longitudinal sectional view, FIG. 2 is an explanatory view of an electrostatic shield action, and FIG. 3 is an electromagnetic shield action. FIG. 4, FIG. 4 is an explanatory view of magnetic shielding, FIG. 5 is a perspective view of a winding formed by using an electric insulating tape, and FIG. 6 is a view on arrow VI of FIG. 7 to 9 are diagrams for explaining a conventional example, FIG. 7 is an explanatory diagram of a measure for preventing noise propagation through an electrostatic capacitance, and FIG. 8 is a diagram for preventing noise propagation by an electromagnetic induction action. FIG. 9 is a sectional view taken along line IX-IX in FIG. 8 for explaining the countermeasure. 1 ... Electrostatic shielding material, 2 ... Shielding material, 3 ... Conductor, 4 ... Insulating coating, 5 ... Iron core, 6 ... Magnetic material, P ... Primary winding, S ... Secondary winding line.

Claims (1)

[Claims] 1. A noise prevention device, wherein an electric wire in which an outer circumference of a conductor body insulated by an insulating material is covered with a magnetic material having a resistivity lower than that of the insulating material is used for a primary winding and a secondary winding, respectively. In the transformer, a noise prevention transformer characterized in that the magnetic material is brought into close contact with the entire surface of the conductor wire covered with insulation without a gap, and the magnetic materials of the primary winding and the secondary winding are respectively grounded.