JPS62199003A - Zero-phase current transformer - Google Patents

Abstract

PURPOSE:To increase coercive force in high frequency to obtain a current transformer with large capacity and superior characteristics in respect to temperature, by using a Co-group amorphous alloy as an iron core for a zero-phase current transformer and lowering its Curie temperature below 180 deg.C. CONSTITUTION:A zero-phase current transformer ZCT is used as a current sensor in a leak breaker. An iron core, around which a Co-group amorphous alloy is wound or piled, is used for the ACT. Curie temperature of the Co-group amorphous alloy is made 180 deg.C or below, and the magnetic strain value lambdas of the Co-group amorphous alloy is made to come to 0<=lambdas<=+3X10<-6>. And, the coercive force at high frequency is increased, with the zero-phase current transformer having large capacity and superior characteristics in respect to temperature and the load is cut off in a relay circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a zero-phase current transformer that uses a Co-based amorphous alloy and has high output and excellent temperature characteristics.

[Technical background of the invention and its problems]

A zero-phase current transformer (ZCT) is used as a type of current sensor such as an earth leakage breaker. As an example using ZCT7, FIG. 1 shows the basic configuration circuit of a leakage TIvx disconnector.

ZC'I't - Current flows in opposite directions in the two conductors passing through it. 5 Normally, when viewed as the primary current of ZCT, they cancel out (11 - I2:O) Therefore,
The induced voltage on the secondary side is zero. When a current leakage occurs at a certain point in the conducting wire, a primary current exists as a result of a large amount of electricity, and an induced voltage is generated on the secondary side. This activates a portion of the relay connected to the conductor, cutting off the current. in this way.

9. It is necessary to detect minute currents. It is an important condition for the material used as the ZCT to have high magnetic permeability, particularly high initial magnetic permeability in order to increase overall sensitivity. It is also necessary that the temperature characteristics be stable. Conventionally, such materials include 80%Ni.
-Fe alloy is used, but it has been desired to obtain even higher secondary output. Also, 80% Ni-
The temperature characteristics of the secondary output of Fe alloys change significantly below room temperature, and a stable ZCT of the secondary output is required over a wide temperature range.

[Object of the present invention]

The present invention has been made in view of the above problems, and provides a ZCT with high output (high sensitivity) and stable temperature characteristics.

[Summary of the invention]

The present invention is characterized by using a Cog amorphous alloy as the magnetic core of the ZCT, thereby achieving high output and stable temperature characteristics.

The CO-based amorphous alloy used here satisfies the above characteristics when the Curie temperature is 180° C. or higher and 300° C. or lower. When the Chieri temperature is above 300°C and below 180°C, the temperature characteristics of the secondary output deteriorate. Preferably, the Curie temperature is 200°C or more and 280°C or less.

Furthermore, among these CO-based amorphous alloys, a ZCT with particularly stable temperature characteristics and high output can be realized with a composition in which the saturation magnetostriction constant λs is in the range of O≦λs≦+3×1o−15, and more preferably O≦λs≦ +I x 10-6 range. When λs is 3X10-6 or more, the value of the secondary output is small (Ql). On the other hand, when λs is λs (Q), the temperature stability becomes poor.

When this is expressed as a compositional formula, the general formula (Co1-a-bFeaMb)1oo-x-y 81x
By However, Okua≦0.12 0≦b≦0.15 0≦X≦25 5≦y≦35 M: Ti, V, Cr, Mn, Ni, Cu, Z
r, Nb, Mo, HfTa, W, at least one member selected from the platinum group O≦λs≦5×10-'
A composition satisfying 180°C≦Tc≦300°C is preferable.

Here, the F edge is the most effective element for adjusting the magnetostriction within the above range, and depending on the type and amount of the additive element M, Q(a≦0
．． This can be achieved within a range of 12. Specifically, when using a normal non-magnetic element as M, 0.04≦a≦0.0
8, but if M n k is used, Q
(Realized with a≦0.04 and using hNit-, a is 0.
07 or more, λs falls within the above range. M improves the thermal stability of magnetic properties, especially Zr, Nb, Mo
.

Hf, Ta, and W also increase the crystallization temperature, but b
When ≧0.15, the Chieri temperature decreases and is not practical.

B is an element essential for amorphous formation, and Si is an element that supports the ability to form an amorphous state. Bt is not practical when Y≧35at%, as the +7 temperature decreases.

It is effective for rising.

After stacking, strain relief heat treatment is performed at a temperature below the crystallization temperature or more than one Curie temperature, but if necessary, heat treatment in a magnetic field may be performed after this. Alternatively, cooling may be performed at a rate within this range.

In general, amorphous alloys are produced by rapidly cooling an alloy material with a predetermined composition ratio from a molten state at a cooling rate of 105'C/sec or more (
It is known that it can be obtained by the liquid quenching method). The amorphous alloy of the present invention can also be easily produced by the conventional method described above. This amorphous alloy.

It is substantially difficult to manufacture a thin ribbon using the liquid quenching method, and if the thickness exceeds 25 μ-, the coercive force at high frequencies increases. do.

(Example-1) (CoO, 94FsO, 06)'71 by single roll method
Suppose that an amorphous alloy ribbon with a composition of 8i 16B13 is prepared, and the magnetostriction constant of this alloy is λs-4X10''7 and the Curie temperature is 228°C. After shaping the obtained amorphous alloy ribbon into a toroidal core having an outer diameter of 18 m5 + an inner diameter of 12 m + 111 m, the core was subjected to a conventional heat treatment for strain relief.

The core is placed in a case, and a small current is passed through the conductor that passes through the magnetic core and is wound with 100 turns as a secondary winding.
Be sure to measure the induced voltage on the next side. -The temperature characteristics were also evaluated using the same sample.

For comparison, a similar evaluation was performed on an 804Ni-Fe alloy having the same core shape.

The results are shown in Figure 2. The secondary output values at room temperature are 170 mV for amorphous alloy, 120 mV for 80% N1-F, and e alloy, respectively. As mentioned above, the output value has been significantly improved, and as can be seen from FIG. 2, the amorphous alloy is more stable in its temperature characteristics.

Table (Example-2) Magnetic cores made of the amorphous alloys listed in the table were produced in the same manner as in Example. Regarding these characteristics, after performing a heat treatment to remove distortion, all necessary characteristics as a ZCT were evaluated. Similar evaluations were also carried out for the compositions listed in Comparative Examples, with a ratio of 11 tl to 11 tl. The evaluation result is 1
When expressed as the secondary output (E2) when = 10 mA and the rate of change from -20℃ to 80℃ (E2/E2(20)) for the secondary output at room temperature, the results are summarized in Table 1. became. That is, Tc and λ are within the range of the present invention.
In the composition containing 3, s ”2, E2/E2 (2
0), good results have been obtained.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide a ZCT with high output and excellent temperature characteristics, and its industrial value is significant.

[Brief explanation of drawings]

Fig. 1 is a basic circuit diagram of a t@ electric interrupter using ZCT, and Fig. 2 is a diagram of the amorphous alloy of the present invention and 80-inch N i F.
Temperature characteristic diagram of secondary output of e-alloy. Agent Patent Attorney Noriyuki Chika Yudo Kikuo Takehana Figure 1

Claims (2)

[Claims] (1) In a zero-phase current transformer equipped with a magnetic core formed by winding or laminating a Co-based amorphous alloy, the Co-based amorphous alloy has a Curie temperature of 180°C or more and 300°C or less. Current transformer. (2) Co-based amorphous alloy has a magnetostriction value (λs) of 0
The zero-phase current transformer according to claim 1, wherein the zero-phase current transformer is in the range of ≦λs≦+3×10^-^6.