JPS63133513A - Current transformer - Google Patents

Abstract

PURPOSE:To prevent a light emitting diode from breaking down and disconnecting while expanding the lower and upper limit of primary current wherein conductivity can be displayed by a method wherein a saturated part saturating current in a large current region and an unsaturated part not saturating current in a small current region are provided in parallel with each other in a part of magnetic channel of a magnetic core. CONSTITUTION:A cylindrical magnetic body 25 in high magnetic permeability, a secondary winding 24 and a primary winding 23 are concentrically contained in a winding containing recession 21a of a core 21 constituting a magnetic core main body 29 while another halved core 22 is bonded to the core 21. The cores 21, 22 are made of,e.g., Mn-Zn base ferrite while the cylindrical body 25 formed of magnetic ally soft material such as amorphous one, etc., makes a shape encircling a butting part 29a. Thus, the magnetic body 25 becomes a saturated part 27 while the butting part 29a of magnetic core main body 20 becomes an unsaturated part 28. Resultantly, within a current transformer connected to a light emitting diode, the light emitting diode current is increased in a small current region but to be decreased in a large current region.

Description

[Detailed Description of the Invention] [Technical Field] The present invention is used for a energization display device, in which a primary winding is inserted into a energization path to a load, a light emitting diode is connected to a secondary winding, and a light emitting diode is connected to an i-load. This relates to a current transformer that detects energization and lights up a light emitting diode.

[Background technology]

In household wiring equipment, incandescent lamps, f
There is a switch device with a built-in pyro-nod lamp that uses a switch device to turn on and off power to a load such as an n-light lamp, and indicates that power is being applied to the load by lighting up a light emitting diode.

Such a switch device is used for a load having a load current of 0.05 A to 15 A, and is particularly used for indoor monitoring of power supply to gatepost lights and entrance lights.

FIG. 7 is a circuit diagram showing the connection relationship between the above-mentioned switch device and the commercial power supply and load. and loads (incandescent lamps, fluorescent lamps, electric appliances, etc.) 3 are commercial electricity I! Ii! 4, and a light emitting diode 5 is connected to the secondary winding of the current transformer 2.

In this circuit, when switch body 1 is turned on,
1 of current transformer 2 through negative 83 from commercial power supply 4
A large current ■1 flows through the next winding, and the current transformer 2's 2
The light emitting diode 5 connected to the secondary current S* is turned on by the secondary current 12.

The light output of the light emitting diode 5 is proportional to the current flowing through the light emitting diode 5, but this characteristic depends on the amount of load current, the characteristics of the current transformer 1, and the characteristics of the light emitting diode 5.

The load of gatepost lights and entrance lights that are often used is IO.
Since it is small (W or less), the load current is small, and the light emitting diode current and light output are small. However, from the user's perspective, since it is used to confirm energization, it is necessary to obtain a light output of a certain level or higher, no matter what the load value is.

Although the current transformer 2 is designed taking the above points into consideration, its dimensions and electrical characteristics are limited, particularly depending on the material and characteristics of the magnetic core.

Figure 8 shows a perspective view of the external appearance of a switch device (WN5241 manufactured by Hiroshi Electric Works) whose load current is rated from 0.1A to 4A, and Figure 9 shows a sectional view of the lower housing.
Figure O shows a plan view of the lower housing. This switch device has a structure in which a lower housing 11 is covered with an upper housing 12, and a current transformer 13 is housed in one side of the internal space of the lower housing 11, and a contact part is provided in the other side.

The upper housing 12 houses a spring etc. (not shown).
A seesaw-shaped knob 14 is attached to the terminal, and the contacts are opened and closed by rotating this knob 140. Knob 1
4 is provided with a window, and the light emitting diode 15 is integrally fixed with the light emitting portion of the light emitting diode 15 exposed through the window.

As shown in the 11th WJ, the current transformer 13 has two
Consisting of a roughly E-shaped core 21 and core 22 made of divided ferrite, a primary winding 23 and a secondary winding 24, the primary winding 23 and the secondary winding are placed in the winding housing recess 21a of the core 21. 24 are fitted concentrically, and the core 22 is bonded to the core 21 with an adhesive, so that the cores 21 and 22 form a closed magnetic circuit. External dimensions a, b, C1, C2 of this current transformer 13
are respectively 16.5mm, 15m, and 3.75f1. i7
It is the 5th.

Although there is a strong demand for such a switch device to be small and lightweight, the current transformer 13 cannot currently be made smaller than the above-mentioned dimensions.

The light emitting diode current, which is proportional to the optical output of the current transformer, increases in proportion to the primary current (load current) of the current transformer. Therefore, the primary current is 0.1 A
The light emitted from the light emitting diode is weak in a small current range of about 4 A, and the light emitted by the light emitting diode becomes strong in a large current range where the primary current is around the rated 4A.

In order to confirm energization by lighting a light-emitting diode, the higher the light output in a small current range, the better.Therefore, GaP-based light-emitting diodes, which have high luminous efficiency in a small current range, are used as light-emitting diodes to indicate energization. There is.

Figure 12 shows the relationship between the typical DC forward current It (mA) and the luminous intensity [0 (mad) of a GaP-based light emitting diode. The solid line A2 shows the characteristics of a GaAs P orange light emitting diode, and the solid line A3 shows the characteristics of a GaP red light emitting diode.

As is clear from FIG. 12, the GaP-based light emitting diode has high luminous intensity in a small current range.

In this way, when GaP-based light emitting diodes are used to indicate energization, it is possible for a person to visually confirm whether the light is on or off even in a small current range. The minimum light emitting current value that can be used is determined, and by increasing the transformation ratio of the current transformer, it is possible to visually confirm whether the light emitting diode is turned on or off even if the primary current is even smaller. However, when the transformation ratio of the current transformer is increased, when the primary current reaches around the rated value, the light emitting diode current becomes excessive and the light emitting diode overheats, causing the light emitting diode to be destroyed or disconnected. There was a problem that the possible primary current range was narrow.

To solve this problem and widen the primary current that can be displayed as energization, increase the transformation ratio of the current transformer in the small current range, and reduce the transformation ratio of the current transformer in the large current range. 1, which can be displayed by increasing the light output.
As the lower limit of the primary current range expands and the light emitting diode current decreases in the large current range, the upper limit of the primary current that can be displayed will expand, but the current transformer shown in Figure 11 is I couldn't design it.

[Purpose of the invention]

An object of the present invention is to provide a current transformer that can widen the range of primary current that can be displayed as energization.

[Disclosure of the invention]

The current transformer of this invention has a primary winding wound around a magnetic core of 1ffi1! In a current transformer in which a light emitting diode is connected to a secondary winding inserted in a detection circuit and wound around the magnetic core, a part of the magnetic path of the magnetic core has a saturation part that saturates in a large current range and a saturated part that saturates in a large current range. It is characterized by providing an unsaturated portion that is not saturated in parallel.

According to this configuration, a saturated part that saturates in a large current range and an unsaturated part that does not saturate in a large current range are provided in parallel in a part of the magnetic path of the magnetic core, so that the small current range of the primary current In this case, the magnetic flux passes through both the saturated and unsaturated parts, and the magnetic resistance is small, so the transformation ratio in the small current range becomes large, and in the large current range of the primary current, the magnetic flux only passes through the unsaturated part, and the magnetic resistance is small. The resistance is large, so the transformation ratio in the large current range is small. As a result, it is possible to increase the light output of the light emitting diode in a small current range and to suppress the light emitting diode current in a large current range, thereby preventing destruction and disconnection of the light emitting diode. Therefore, the lower and upper limits of the primary current that can be displayed by the light emitting diode are expanded.

Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIGS. 1 and 2, this current transformer has a primary winding 23 wound around a magnetic core 26 inserted into a current detection circuit, and a secondary winding 24 wound around the magnetic core 26.
In a current transformer (see Fig. 7) in which a light emitting diode for energization indication is connected to the energization state, a part of the magnetic path of the magnetic core 26 has a saturated portion 27 that saturates in the large current range of the primary current and a large current region of the primary current. It is characterized in that an unsaturated portion 28 that does not saturate in the basin is provided in parallel.

In this case, the magnetic core 26 is composed of a magnetic core main body 29 having an abutting portion 29a, and a cylindrical high permeability magnetic body 25 disposed so as to surround the abutting portion 29a of the magnetic core main body 29. The magnetic body 25 becomes a saturated portion 27 and the abutting portion 29a of the magnetic core body 29 becomes an unsaturated portion 28.

This current transformer concentrically accommodates a cylindrical high permeability magnetic body 25, a secondary winding 24, and a primary winding 23 in a Ti wire housing recess 21a of a core 21 constituting a magnetic core body 29. The other two-part core 22 is bonded to the core 21.

The cores 21 and 22 mentioned above are made of Mn-Zn ferrite. The magnetic body 25 has a cylindrical shape, and the abutting portion 29
The material is a soft magnetic material such as ferrite, permalloy, or amorphous. A magnetic core was made and used as the magnetic body 25.

The following table shows the magnetic properties and annealing conditions of this magnetic material.
It can be seen that the magnetic permeability of this material is extremely high at 750,000 in terms of μlin aX.

(Leaving space below) Table 1 A light emitting diode is connected to the secondary winding 24 of the prototype current transformer, the primary winding 23 is inserted into the current detection circuit, and a current is passed through the primary winding 23 to The side light emitting diode current was measured. The measurement results are shown in Figure 3. In Figure 3, the horizontal axis represents the primary current and the vertical axis represents the light emitting diode current. In Figure 3, the solid line B1 represents the characteristics of the current transformer of this example. The broken line B2 indicates the characteristics of the conventional current transformer. From Figure 3, in the small current range where the primary current is 0.1A, the light emitting diode current increases by 5% compared to the conventional ratio, and in the large current range where the primary current is 4A (large a rating), the light emitting diode current increases by 20%. % decreased to 40 mA, which is below the maximum rating of the light emitting diode. That is, in the current transformer of this embodiment, compared to the conventional example, the light emitting diode current increases in the small current range and decreases in the large current range.

Although there is no clear answer as to the cause of this,
This is thought to be due to the following effects. That is,
Considering the flow of magnetic flux in the magnetic core 26 in this current transformer with respect to the center of the magnetic core 26 and its surroundings,
When the primary current is in a small current range, as shown in FIG. 4 ta+, magnetic paths C1l and C10 pass through the abutting portion 29a, and magnetic paths C21 and C21 bypass the abutting portion 29a and pass through the magnetic body 25.
There is C22.

In this case, the magnetic paths C11 and CI2 are connected to the abutting portion 29a.
The magnetic path C2+ has a magnetic resistance R, as shown in Fig. 4 (C
1, the magnetic path C22 has a magnetic resistance RL l +RL 2 due to the joint between the magnetic core body 29 and the magnetic body 25, and the magnetic path C22 is
Similarly, it has magnetic resistance RL 3 +RL 4 due to the joint between the magnetic core body 29 and the magnetic body 25.

In the small current range, the magnetic flux forms the magnetic path CII + CI2'+
C21+C22, the composite magnetic resistance RP of the central leg of the magnetic core 26 and its surroundings is RP=RM/(RL t +RL2)//(RL3+R
L4)=(RM (RL 1+RL2)(RL3+
RL4))/(RM (RLl+RL2)+RM
(RL3+RL4)+(RLl+RL2)(RL3+R
L4)), and R,>RP.

On the other hand, in the large current region, the magnetic body 25 is saturated and the magnetic flux is
Figure (as shown in bl, magnetic path C11, CI2.CI3+ C
14 and does not pass through the magnetic body 25. At this time, the magnetic resistance RM of the central leg of the magnetic core 26 and its surrounding area
The magnetic resistance becomes larger in the large current range than in the small current range.

As described above, in the small current range of the primary current, the magnetic resistance is small and the magnetic flux passes through easily, the transformation ratio is large, and the ratio of the secondary side light emitting diode current to the primary current increases. On the other hand, in a large current range, the magnetic resistance becomes large and the magnetic flux is difficult to pass through, and the transformation ratio is small and the ratio of the secondary side light emitting diode current to the primary current becomes small. In other words, in this example, In a small current range, the magnetic body 25 acts as a path for magnetic flux, increasing the proportion of light emitting diode current on the secondary side, and in a large current area, the magnetic body 25 is saturated and the magnetic path is cut off, causing light emission on the secondary side. This appears to be because the proportion of diode current becomes smaller.

Such a feature was unimaginable in conventional current transformers, and the effect in current transformers used for energization indication by connecting a light emitting diode to the secondary side is tremendous.

Note that the magnetic material may not only be placed so as to surround the abutting portion 29 of the center leg, but may also be placed only in a part of the periphery, or may be placed around the abutting portion of the side leg. A similar effect can be obtained.

In the above embodiment, an amorphous magnetic material was used as the magnetic body 25, and a GaP-based material was used as the light emitting diode. Of course, the same effect can be obtained by using a magnetic material such as a silicon steel plate, or by using a GaAsP-based light emitting diode.

A second embodiment of the invention will be described based on FIGS. 5 and 6. This current transformer has a magnetic core 33 by forming a notch 32 in a part of the magnetic path of an elliptic toroidal magnetic core main body 31, and a primary winding 34 and a secondary S
The wire 35 is wound around the wire 35.

In this case, the neck portion 36 of the magnetic core body 31 formed by the notch 32 becomes a saturated portion 37, and the notch 32 becomes an unsaturated portion 38.

The magnetic core body 31 is made of an amorphous magnetic ribbon (260532 manufactured by Allied Co., Ltd., composition Fe?8B+:+S i
g) is formed by winding it. The amorphous magnetic ribbon was annealed at 400° C. for 2 hours while applying a magnetic field of 40 oe, and cooled at a cooling rate of 5° C./min.

In the case of this embodiment, when the primary current is in the small current range, the magnetic flux passes through the neck 36 as shown by the arrow in FIG.
The ratio of the light emitting diode current to the next current can be increased. In addition, in the large current region, the neck 36 is saturated and the magnetic flux passes through the notch 32 (which becomes a gap), and this part has a large magnetic resistance, so the metamorphic ratio is small, that is, the 51st order. The ratio of the light emitting diode current to the current can be reduced.

In this embodiment, since no magnetic material is newly provided, the structure is simpler. The rest is the same as the first embodiment.

There are no particular restrictions on the materials of the magnetic core 33 and magnetic body 25 that constitute the current transformer, but materials with high magnetic permeability,
An amorphous magnetic ribbon that can achieve high magnetic flux density is desirable.

〔Effect of the invention〕

According to the current transformer of the present invention, a saturated part that saturates in a large current range and an unsaturated part that does not saturate in a large current range are provided in parallel in a part of the magnetic path of the magnetic core, so that the primary current can be used in a small current range. In this case, the magnetic flux passes through both the saturated and unsaturated parts, and the magnetic resistance is small, so the metamorphic ratio in the small current region becomes large, and 1
In the large current region of the next current, the magnetic flux only passes toward the unsaturated portion, resulting in a large magnetic resistance, and therefore the metamorphic ratio in the large current region becomes small. As a result, the light output of the light emitting diode in the small current range is increased, and the light emitting diode current in the large current range is suppressed, thereby destroying the light emitting diode.

Can prevent wire breakage. Therefore, the lower and upper limits of the primary current that can be displayed by the light emitting diode are expanded.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the current transformer according to the first embodiment of the present invention, and the second Fl! J is an exploded perspective view of the same, FIG. 3 is a characteristic diagram showing the relationship between the primary current and light emitting diode current of the embodiment and the conventional example, FIG. 4 is an explanatory diagram showing changes in the magnetic path, and FIG.
Figure 6 is a perspective view of a current transformer according to a second embodiment of the present invention, Figure 6 is a sectional view thereof, Figure 7 is a circuit diagram of a conventional switch device with a built-in pilot lamp, and Figure 8 is a perspective view of the switch device. Figure 9 is a sectional view of the main part, Figure 10 is a plan view of the main part, Figure 11 is an exploded perspective view of a conventional current transformer, and Figure 12 is the relationship between forward current and luminous intensity of various light emitting diodes. FIG. 23...Primary winding, 24...Secondary winding, 25...
Magnetic material, 26...Magnetic core, 27...Saturation part, 28...
・Unsaturated part, 29...Magnetic core body, 29a...Abutting part→l; Lack of electricity it (actual value) (b) (C) Fig. 4 Fig. 5 Fig. 6 Fig. 9 Figure 11 Figure 12

Claims (3)

[Claims] (1) In a current transformer in which a primary winding wound around a magnetic core is inserted into a conduction detection circuit, and a light emitting diode is connected to a secondary winding wound around the magnetic core, one of the magnetic paths of the magnetic core is A current transformer characterized in that a saturated part that saturates in a large current range and an unsaturated part that does not saturate in a large current range are provided in parallel. (2) The magnetic core is composed of a magnetic core main body having an abutting portion, and a high magnetic permeability magnetic material disposed around the periphery of the abutting portion of the magnetic core main body, and the magnetic material is connected to the saturation portion. The current transformer according to claim 1, wherein the abutting portion of the magnetic core body is the unsaturated portion. (3) The magnetic core is composed of a magnetic core body and a notch provided in a part of the magnetic path of the magnetic core body, and the neck of the magnetic core body formed by the notch serves as the saturation part. The current transformer according to claim 1, wherein the cutout is an unsaturated portion.