JPS61198611A - Manufacture of transformer with amorphous alloy thin band core - Google Patents

Abstract

PURPOSE:To facilitate handling, and to simplify an annealing furnace, by a method wherein a core made mainly of an amorphous alloy thin band is wound with a conductor coated with an electric insulating coat having a heat resistance of 300 deg.C or more, and the core is annealed under a magnetic field accompanying the conduction to this heat-resistant coat conductor; thereafter, the conductor is used both for the primary and/or for the secondary windings. CONSTITUTION:The core made mainly of an amorphous alloy this band is wound with a conductor coated with an electric insulating coat having a heat resistance of 300 deg.C or more. Said core is annealed under a magnetic field accompanying the conduction to this heat-resistance coat conductor, and the conductor is then used both for the primary and/or for the secondary windings. A conductor coated mainly with e.g. a boro siloxane series resin has a heat resistance of 300 deg.C or more and is endurable to annealing for a magnetic field. Winding it around a wound core made mainly of amorphous alloy thin band enables use for the auxiliary heating for the field generation during field annealing and for the annealing temperature and then the function as the primary and secondary windings of the transformer after field annealing.

Description

[Detailed Description of the Invention] (Industrial Application Field) Regarding power transformers or high-frequency transformers, especially transformers whose core is annealed in a magnetic field, and whose core is an amorphous magnetic alloy ribbon. An advantageous method of manufacturing a transformer is described below.

Amorphous alloy ribbons such as Fe-B and Fe-B-Si have excellent soft magnetism and especially extremely low core loss, so they are used as grain-oriented silicon steel sheets currently used as core materials for transformers. It is attracting attention as a powerful competitive material.

Furthermore, certain amorphous alloy ribbons have high magnetic permeability and excellent high frequency characteristics, and are used as magnetic materials for electronic devices.

In order to maximize the magnetic properties of iron cores using these amorphous alloy ribbons, annealing in a magnetic field is often required to control the arrangement of magnetic domains.

In the case of a power transformer, the magnetic domains must be aligned in the axial direction of the ribbon, so the direction of magnetic flux during magnetic field annealing must be parallel to the longitudinal direction of the ribbon. Annealing a single plate under a parallel magnetic field is easy even from outside the furnace. However, annealing the amorphous alloy ribbon at high temperatures makes it brittle and inconvenient to handle, so it is necessary to perform magnetic field annealing after forming it into an iron core such as a wound core.

After forming into a wound core, a uniform external magnetic field from outside the annealing furnace cannot cause a magnetic field parallel to the longitudinal direction of the ribbon to act on all parts of the core.

(Prior technology) □ Attempts have been made to generate a magnetic field along the longitudinal direction of the ribbon by passing a thick conductive wire through the center of a wound core formed by winding an amorphous alloy ribbon in advance and passing a large current through the core. Ta. However, since the number of turns of the coil winding could not be made sufficiently large, an extremely large current had to be passed in order to obtain the required magnetic field strength.

On the other hand, in power transformers, etc., the primary and secondary windings are ultimately installed, so if these windings can also be used to generate a magnetic field during annealing, the amount of current can be reduced, and the annealing equipment However, oil-based enamelled wires and formal wires, which have been conventionally used as winding materials, lose their insulation properties when annealed at temperatures above 200°C. It was not possible to apply winding prior to magnetic field annealing, which was carried out at °C.

(Problems to be Solved by the Invention) The number of turns of the primary and/or secondary winding of a transformer is large, and by utilizing this as a heating and excitation coil for annealing in a magnetic field, it is difficult to solve the conventional problems. The purpose of this invention is to derive benefits that were previously impossible.

(Means for Solving the Problems) This invention involves winding a conductive wire coated with an electrically insulating paint having the highest heat resistance of 300'C around an iron core mainly made of an amorphous alloy ribbon. A method for manufacturing a transformer using an amorphous alloy ribbon core, characterized by annealing the nine-iron core under a magnetic field caused by energization of the conductor, and then using the conductor for the primary and/or secondary winding. It is.

Here, for example, there are few conductive wires (for example, MP wire or MK wire manufactured by Showa Cable and Wire Co., Ltd.) coated with a coating material mainly composed of borosiloxane resin, such as one made of borosiloxane resin, silicone resin, and inorganic filler. Both types have heat resistance of about 300°C or higher and can withstand annealing in a magnetic field. Not only is it used to generate the magnetic field at the time of heating, but it is also used for auxiliary heating to the annealing temperature, and after passing through the magnetic field and annealing, it functions as the primary and secondary windings of the transformer.
It became clear that it could be done.

(Function) That is, the inventors used Fet with a board width of 2 cm and a board thickness of 25 μm.
sB+. A toroidal core with an inner diameter of 6cII was made by winding an amorphous alloy ribbon having the composition Sit□, and then a conducting wire (M
P wire) using a primary winding of 50 turns and a secondary winding of 200 turns.
Made a turn.

When this toroidal core is annealed in a magnetic field at 370°C for 30 minutes, the magnetic field is connected in such a way that the direction of the magnetic field generated by each winding is the same, and the strength of the magnetic field is 200^/m.
The current value was adjusted so that

This annealing did not cause poor insulation resistance of the wire coating.

On the other hand, changes in thermogravimetric analysis and infrared absorption spectra of the coating material show that even after heat treatment at elevated temperatures of up to 400°C during annealing, the weight of the coating material only decreases by about 20%.
In addition, residual inorganic fillers, 5i-0 bonds, and B-0 bonds were confirmed.

From this, it is considered that both the primary and secondary windings maintain the necessary insulation resistance.

After magnetic field and annealing, remove the excitation connection between the primary and secondary windings,
When we tested the toroidal core as a single-phase transformer, we were able to extract a voltage from the secondary side that corresponds to the turns ratio of the primary and secondary windings.

In this way, with the conventional method, it was possible to obtain exactly the same performance as when newly winding the primary and secondary windings after magnetic field annealing.

Since the amorphous alloy ribbon becomes brittle after annealing, it had to be handled extremely carefully and carefully in the conventional method, but in this invention, the strength of the alloy ribbon is greater before annealing. Since the winding construction is completed in stages, handling is extremely easy.

In this regard, when producing an iron core by winding a non-premium alloy thin strip, at least one turn and at most several turns, including the innermost and outermost turns, should be combined with a silicon steel plate, preferably a grain-oriented silicon steel plate. It has been found that assembling the core in multiple steps significantly improves the workability of wire winding.

(Example) A single-phase wound core with a capacity of 0.5 KVA was manufactured using amorphous alloy ribbons having two types of FellB+oSil□ compositions with an average plate thickness of 26 μ- and a plate width of 50 mm and 25++uw. MP wire was used for the wire.

It was then annealed in N2 gas at 370° C. for 30 minutes, and during heating and cooling the windings were energized to generate a magnetic field of 250^/I11 parallel to the longitudinal direction of the ribbon.

At this time, there was no short circuit between the windings.

When the characteristics of the transformer manufactured in this way were measured, the iron loss at 50 Hz and 1.3 T was 0.24 W/kg, and the noise was only 35 phon.

(Effects of the Invention) According to the method of the present invention, a transformer core is created by winding an amorphous alloy ribbon in an unannealed state with high toughness, and winding is applied to this, making handling extremely easy. Because of magnetic field annealing, there is no need to install a new coil in the annealing furnace, which simplifies the annealing furnace.

Claims (1)

[Claims] 1. A conductor wire coated with an electrically insulating paint having heat resistance of 300°C or more is wound around an iron core mainly made of an amorphous alloy ribbon, and as electricity is applied to the heat-resistant coated conductor wire. A method for manufacturing a transformer using an amorphous alloy ribbon core, characterized in that the core is annealed in a magnetic field, and the conductor is then used for primary and/or secondary windings. 2. The amorphous alloy ribbon core according to 1, wherein the core is a composite wound body containing a silicon steel plate having at least one turn including the innermost turn and the outermost turn of the amorphous alloy ribbon wound body. manufacturing method.