JP2001110651A - Thunder surge shield transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely shield a thunder surge current, naturally of a common mode noise component but also of a normal mode noise component which contains a large amount of high frequency components. SOLUTION: A thunder surge shield transformer is constituted by housing the insulating transformer of the same axis and different cores composed of a primary coil 10 wrapped with a first electromagnetic shield plate, a secondary coil 20 wrapped with a second electromagnetic shield plate, an iron core 30 and an intermediate electromagnetic shielding plate 40 in a case 50 of conductive materials. The intermediate electromagnetic shielding plate 40 is fixed on a frame 51. A primary side ground terminal 17, to which the first electromagnetic shielding plate is connected, and a secondary side ground terminal 27, to which the second electromagnetic shielding plate is connected, are respectively attached on the left and right side plates of the case 50, and further a frame ground terminal 41 is attached to the frame 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention interrupts a lightning surge that penetrates into and conducts electric power lines and damages precision electronic equipment, information equipment, automatic control equipment, and the like, and protects these electric and electronic equipment. Related to a lightning surge cut-off transformer.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram for explaining how a lightning surge current flows in a circuit for supplying electric power from a commercial power supply 5 to an electric device 6 via a transformer. The transformer is an insulating transformer composed of a primary coil 1, a secondary coil 2, an iron core 3, and an electrostatic shielding plate 4. Lu and Cu are the inductance component and the capacitance component of the ground impedance of the U-phase line,
Lv and Cv are an inductance component and a capacitance component of the ground impedance of the V-phase line. Furthermore, Cs
Is the capacitance distributed between the primary coil 1 and the electrostatic shielding plate 4 and between the secondary coil 2 and the electrostatic shielding plate 4.

[0003] From the viewpoint of electrical equipment and the like installed on the ground, a lightning surge is a common mode noise that forms a huge loop from the sky to the ground. After the lightning surge enters the power line, the lightning surge is not 100% common mode noise, but a noise in which a common mode noise component and a normal mode noise component are combined. As can be understood from FIG. 6, there is always a remarkable difference in the ground impedance of the electric line between the two reciprocating lines, and there is also a considerable difference in the impedance and its distribution state inside the transformer. A certain lightning surge current has a significant difference in level and phase between two wires.

As a result, the lightning surge current Iu traveling from the U terminal to the V terminal of the primary coil 1 of the transformer and the lightning surge current Iv traveling in the opposite direction are mostly canceled in the primary coil 1. Therefore, the components of the difference between the lightning surge currents flow through the primary coil 1 as lightning surge currents of a large amount of normal mode noise components. Then, the lightning surge current of the normal mode noise component shifts from the primary side to the secondary side due to the inherent electromagnetic induction of the transformer. The transfer of the lightning surge current of the normal mode noise component to the secondary side due to the electromagnetic induction cannot be prevented by the electrostatic shielding plate 4 disposed between the primary coil 1 and the secondary coil 2. This is because the electrostatic shielding plate does not participate in electromagnetic induction in principle.

[0005] Japanese Patent Application Laid-Open No. Hei 6-77063 discloses that an iron core on which a coil is to be wound is moved from the input side to the output side.
A first insulating layer, an input side winding, a second insulating layer, a first shielding plate, a third insulating layer, a second shielding plate, a fourth insulating layer, and a third shielding plate which are directly in contact with the iron core , A fifth insulating layer, an output side winding, a sixth insulating layer, a fourth shielding plate, and a seventh insulating layer are disclosed. in short,
In a coaxial concentric insulating transformer, the input side coil is arranged inside and the output side coil is arranged outside, and three shielding plates are interposed between the input side coil and the output side coil with the insulating layer interposed between the coil and the core. And a light shielding countermeasure transformer in which one shield plate is arranged coaxially with the iron core also on the outer peripheral side of the output side coil. This transformer for lightning protection is configured so as not to affect the electric equipment and the like connected to the output side coil due to the lightning surge of the common mode noise component. Therefore, when the lightning surge current of the normal mode noise component flows through the input coil, the lightning surge current of the normal mode noise component shifts to the secondary side due to the inherent electromagnetic induction of the transformer. In a transformer having an input side coil and an output side coil disposed coaxially and concentrically, three shield plates disposed between an input side coil and an output side coil, and also on an outer peripheral side of an output side coil With one placed shielding plate, the transfer of the lightning surge current of the normal mode noise component containing a large amount of high frequency components to the secondary side cannot be prevented. As described above, the conventional lightning surge cut-off transformer cannot prevent the transfer of the normal mode noise component from the lightning surge to the secondary side.

[0006]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is that it has a reliability that can reliably block not only the common mode noise component of the lightning surge current but also the normal mode noise component containing a large amount of high frequency components. The purpose is to provide a high lightning surge blocking transformer.

[0007]

According to the present invention, there is provided a lightning surge interrupting transformer for solving the above-mentioned problems, comprising a primary coil wrapped by a first electromagnetic shielding plate, a secondary coil wrapped by a second electromagnetic shielding plate, and the primary coil. And a third coil disposed between the secondary coil and the secondary coil.
An electromagnetic shielding plate, an iron core having a shape in which the primary coil and the secondary coil are arranged so as not to be coaxial, and a case made of a conductive material for accommodating them. As the core, an iron core having a shape forming a transformer having a coaxial different core, an iron core having a shape forming a transformer having a different axis different core, or an iron core having a shape having a transformer having a different axis different core twist was used.

A lightning surge cut-off transformer for solving the above-mentioned problems is disposed between a primary coil wrapped by a first electromagnetic shielding plate, a secondary coil wrapped by a second electromagnetic shielding plate, and these coils. A third electromagnetic shielding plate, an iron core having a shape in which these coils are arranged so as not to be coaxial and concentric, and a case made of a conductive material for accommodating them; A primary-side ground terminal, a secondary-side ground terminal, and an intermediate ground terminal, which are provided apart from each other, and the first, second, and third electromagnetic shield plates are respectively connected to these ground terminals. Connected. Further, the primary-side ground terminal, the secondary-side ground terminal, and the intermediate ground terminal are terminals having a holding plate structure to which a belt-like ground connection conductor can be connected.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view schematically showing a case and terminals of an embodiment of the present invention, FIG. 4 is a perspective view showing a state of being assembled to a frame, and FIG. It is a side view of the attached state. As shown in these drawings, a lightning surge blocking transformer according to one embodiment of the present invention includes a primary coil 10 wrapped by a first electromagnetic shielding plate, a secondary coil 20 wrapped by a second electromagnetic shielding plate, Iron core 3 to be the magnetic path of the coil
0, and a coaxial and non-concentric insulating transformer composed of an intermediate electromagnetic shielding plate 40 disposed between the primary coil 10 and the secondary coil 20 and housed in a case 50 made of a conductive material. It is. The intermediate electromagnetic shielding plate 40 includes a frame 51
It is stuck to.

As shown in an enlarged sectional view of FIG. 2, a primary coil 10 is formed by winding a copper wire 11 in a multi-layer and multiple turns, and covers an outer peripheral surface of the coil with an inner insulating layer 12. The coil is formed by wrapping the entire circumference with an aluminum foil 13 and further covering the outer periphery with an outer insulating layer 14. The aluminum foil 13 is a first electromagnetic shielding plate in the present invention. Also, the secondary coil 20 is formed by winding a copper wire in a multi-layer and multi-turn winding, covering the outer peripheral surface of the coil with an inner insulating layer, wrapping it over the entire circumference with aluminum foil, and further covering it thereover. A coil formed by covering with an outer insulating layer, wherein the aluminum foil is a second coil according to the present invention.
It functions as an electromagnetic shielding plate.

The primary coil 10 and the secondary coil 20 are shown in FIG.
As shown in a perspective view in FIG.
One end of the grounding lead wire 15 of the strip is connected to the primary coil 1.
0 is connected to the first electromagnetic shielding plate 13 surrounding the first electromagnetic shielding plate 13.
Similarly, one end of the grounding lead wire 25 of the strip is connected to the second electromagnetic shielding plate of the secondary coil 20. One end of each of the pair of primary lead wires 18 is connected to the beginning and end of the winding of the copper wire 11 of the primary coil 10, respectively, and the other end thereof is connected to the pair of primary terminals 19.
Similarly, one end of each of the pair of secondary lead wires 28 is connected to the start and end of the copper wire of the secondary coil 20, respectively, and the other end is connected to the pair of secondary terminals 29. Have been.

The iron core 30 forming the magnetic path between the primary coil 10 and the secondary coil 20 is made of, for example, an E-shaped iron core piece having a predetermined size manufactured by stamping a non-oriented silicon steel sheet having a thickness of 0.5 mm. It is a general one formed by laminating die core pieces to a predetermined thickness. FIG. 3 is a perspective view showing E-shaped iron core pieces 30a and 30b in a state before being assembled by laminating and assembling the iron core into left and right parts.

The pair of primary terminals 19 and the pair of secondary terminals 29 are attached to the left and right side plates of the case 50, respectively.

A primary side ground terminal 17 and a secondary side ground terminal 27
Are attached to the left and right side plates of the case 50 via insulators, respectively, and the frame ground terminal 41 is attached to the frame 51. Thus, the primary side ground terminal 17, the secondary side ground terminal 27, and the frame ground terminal 4
1 is attached to the case 50 so as to be physically and electrically separated. Each of these three grounding terminals is independently connected to a counterpart ground (grounding pole or chassis). For example, the primary side grounding terminal 17 is connected to the grounding pole of the power supply, and the secondary side grounding terminal 27 is connected to the chassis of the electric device. And ground conductors,
Further, the frame ground terminals 41 are respectively connected to other ground poles of the electric equipment.

The primary side ground terminal 17 is connected to the first electromagnetic shield plate 13 surrounding the primary coil 10 via the first primary coil shield lead plate 15 and the second primary coil shield lead plate 16. Have been. The secondary side grounding terminal 27 is connected to the first secondary coil shield lead plate 25.
And the second secondary coil shield lead plate 26,
It is connected to a second electromagnetic shield surrounding the secondary coil 20. The frame ground terminal 41 is connected to the intermediate electromagnetic shielding plate 40 via a frame 51 made of a conductive material.

As shown in FIG. 5, the primary-side grounding terminal 17 includes a detachable wide holding plate 17a and a detachable tool 17a.
b. The bolts constituting the attachment / detachment tool 17b are erected on the side plate 52 at positions where they contact the ends of the second primary coil shield lead plate 16 fixed to the side plate 52. When a strip-shaped ground wire (not shown), that is, a conductive strip is connected to the primary-side ground terminal 17, the removable wide holding plate 17a is removed from the bolt of the attachment / detachment tool 17b. After the end of the conductive strip is located at a predetermined position on the primary side grounding terminal 17, the conductive strip is pressed by a removable wide pressing plate 17a.
It is fixed by tightening the bolt and nut of 7b. Further, the structure of the secondary grounding terminal 27 attached to the side plate opposite to the side plate 52 is the same as the structure of the primary grounding terminal 17 described above, and is composed of a removable wide holding plate and a detachable tool. It is a thing. Further, the structure of the frame grounding terminal 41 attached to the frame 51 also includes a detachable wide pressing plate and a detachable tool.

In the lightning surge cut-off transformer according to the embodiment of the present invention described in detail above, the lightning surge current of the common mode noise component is supplied to the first electromagnetic shield, which is independently grounded via the ground terminal. It is shielded by the plate, the second electromagnetic shielding plate, and the intermediate electromagnetic shielding plate, and no transition to the secondary side occurs.

On the other hand, a lightning surge current of a normal mode noise component containing a large amount of a high frequency component flows through the primary coil 10, and most of the high frequency component of the magnetic flux due to this current is reduced by the iron core 30 which is a low frequency material for electric power. Instead, the air passes through the air core formed by the air gap or the insulator in the primary coil 10 and the space around the air core. However, the magnetic flux passing through the air core formed of the air gap and the insulator in the primary coil 10 and the space around the core is not the same as the primary coil 10 and the secondary coil 20 are coaxially arranged. Are hardly linked, and electromagnetic induction from the primary side to the secondary side hardly occurs. Therefore, the lightning surge current of the normal mode noise component including a large amount of the high frequency component hardly transfers from the primary coil 10 to the secondary coil 20 due to the electromagnetic induction. Thus, in the lightning surge cut-off transformer according to the present invention, both the lightning surge current of the common mode noise component and the lightning surge of the normal mode component are reliably prevented from shifting from the primary side to the secondary side.

As described above, the lightning surge interrupting transformer according to the present invention employs a ground terminal structure using a conductive band as the ground conductor. By using a conductive band ground conductor instead of a normal ground wire, high-frequency impedance can be reduced. By reducing the high-frequency impedance, the lightning surge current of the common mode noise component can easily flow to the ground, and at the same time, the generation of the high voltage due to the conductor resistance and the radiation of the lightning surge can be reduced.

By the way, it has been described that the transition from the primary side to the secondary side is surely prevented. However, in the lightning surge cut-off transformer according to the present invention, the transition of the lightning surge current from the secondary side to the primary side is also prevented. Of course, it is surely prevented.

In the embodiment, the first and second electromagnetic shielding plates enclosing the primary coil 10 and the secondary coil 20, respectively, are made of aluminum foil. It may be formed. In addition, a conductive material other than aluminum can be used as a material of the electromagnetic shielding plate.

Further, the embodiment in which the iron core 30 is formed of a transformer having a coaxial and eccentric transformer has been described, but the iron core having a shape of a transformer having an eccentric eccentric or a twist of an eccentric eccentric twist is described. It is also possible to use an iron core having a shape constituting a transformer.

[0023]

According to the present invention, a first electromagnetic shielding plate enclosing a primary coil, a second electromagnetic shielding plate enclosing a secondary coil,
And a third electromagnetic shielding plate arranged between the primary coil and the secondary coil to prevent the lightning surge current of the common mode noise component from shifting to the secondary side, and at the same time, the primary coil and the secondary coil And coaxial eccentricity, eccentric eccentricity in iron core,
Alternatively, a transformer having an off-axis and off-center twist can be configured to prevent the lightning surge current of the normal mode noise component from shifting to the secondary side. Therefore, it is possible to ensure not only the common mode noise component of the lightning surge current but also the normal mode noise component containing a large amount of high-frequency components without complicating the configuration as compared with the related art and with little consideration for cost increase. A reliable lightning surge cut-off transformer that cuts off power can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a lightning surge cut-off transformer according to an embodiment of the present invention, in which parts of a case and terminals are simplified.

FIG. 2 is an enlarged sectional view of a primary coil.

FIG. 3 is a perspective view of a primary coil, a secondary coil, and an iron core.

FIG. 4 is a perspective view of an embodiment of the present invention assembled to a frame.

FIG. 5 is a side view of an embodiment of the present invention assembled to a frame.

FIG. 6 is a circuit diagram for explaining a situation in which a lightning surge current flows in a transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 3 Iron core 4 Electrostatic shielding plate 5 Commercial power supply 6 Electric equipment 10 Primary coil 11 Copper wire 12 Insulator 13 Aluminum foil for primary coil shield 14 Insulator 15 Lead plate for primary coil shield 15, 16 Primary Lead plate for coil shield 17 Primary ground terminal 18 Lead wire of primary coil 19 Primary terminal 20 Secondary coil 25, 26 Lead plate for secondary coil shield 27 Secondary ground terminal 28 Lead wire of secondary coil 29 Secondary Side terminal 30 Iron core 30a, 30b Iron core piece 40, 40a, 40b Intermediate electromagnetic shielding plate 41 Intermediate ground terminal 50 Case 51 Frame 52 Side plate

Claims (6)

[Claims] 1. A primary coil wrapped by a first electromagnetic shielding plate, a secondary coil wrapped by a second electromagnetic shielding plate, and a third electromagnetic member disposed between the primary coil and the secondary coil. A lightning surge interrupting transformer comprising: a shielding plate; an iron core having a shape in which the primary coil and the secondary coil are arranged so as not to be coaxial; and a case made of a conductive material for housing the core. 2. The lightning surge cut-off transformer according to claim 1, wherein the iron core is a core having a shape constituting a coaxially different transformer. 3. The lightning surge cut-off transformer according to claim 1, wherein the iron core is an iron core having a shape constituting a transformer having a different axis and a different core. 4. The core according to claim 1, wherein the core has a shape that forms a transformer having a different axis and different core twist.
Lightning surge cut-off transformer. 5. The case is provided with a primary-side ground terminal, a secondary-side ground terminal and an intermediate ground terminal which are provided physically and electrically separated from each other, and the first electromagnetic terminal is provided on these ground terminals. 2. The lightning surge cut-off transformer according to claim 1, wherein the shielding plate, the second electromagnetic shielding plate and the third electromagnetic shielding plate are connected to each other. 6. The terminal according to claim 5, wherein the primary-side ground terminal, the secondary-side ground terminal, and the intermediate ground terminal are terminals having a holding plate structure to which a belt-like ground connection conductor can be connected. Lightning surge cutoff transformer.