JPS5932103Y2 - isolation transformer - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an isolation transformer used in a power supply device for medical electrical equipment, etc., for the purpose of preventing electric shock when a live wire part is grounded or comes into contact with a human body.

Conventional isolation transformers generally have a concentric cylindrical shape or a concentric prismatic shape in which a secondary coil is wound around a secondary coil, but in transformers with this type of structure, The capacitance between the coil and the secondary coil is large, and therefore the leakage current, which is the charging current, is also large, and the structure of the isolation transformer itself becomes large.

This idea was made to eliminate the above-mentioned drawbacks, and it is an isolation transformer that can minimize the leakage current in the event of a ground fault, and also has a compact structure that allows it to be easily embedded in walls, etc. The purpose is to provide

Hereinafter, embodiments of this invention will be described based on the drawings.

Figure 1 shows the top view of the isolation transformer, and Figure 2 shows its x-
A sectional view taken along the oy line is shown.

Reference numeral 1 denotes a wound core in which a band-shaped steel plate is wound in a donut shape.The wound core 1 is covered with an insulator 5, and four clamps 4 are fixed to the outer periphery of the wound core 1.

2 is a primary coil which is wound on the wound core 1 in eight parts P□ to P8, and 3 is a secondary coil.

The secondary coil 3 has Pl and P of the primary coil 2 divided into eight parts.
2. P3 and P4. P, and P6. It is divided into four parts between P7 and P8, and is wound on the wound core 1 as Sl to S4.

A collar-shaped insulator 6 is inserted between the -secondary coil 2 and the secondary coil 3 and between the -secondary coil 2 and the clamp 4.

In this way, in an insulating transformer wound with secondary and secondary coils, the secondary coil 3 divided into four by Sl to S4 is divided into four parts by Pl to S4.
The primary coil 2 divided into 8 parts at P8 is sandwiched from both sides, and the primary coil 2 is inserted along the circumference of the wound core.
The distribution of the leakage magnetic flux density B between the secondary coil and the secondary coil is shown as
It can be expressed as shown in the figure.

Therefore, gaps A1 to A between the divided primary coils 2
Since leakage magnetic flux does not pass through the clamps 4, no stray loss or the like occurs in the clamps 4 made of mild steel or the like, which are fixed to the wound core using the gaps A1 to A4.

Moreover, since the clamp 4 is fixed only to the wound core 1 via the insulator 5, it will not damage the coil.

The insulating transformer having the above-mentioned structure is fixed to a mounting location by legs formed at the lower part of the clamp 4, and is used by grounding one end of the secondary coil 2.

During use, if the wiring connected to the secondary coil 3 or the live wire part of the electrical equipment is grounded due to a human contact accident, a leakage current, which is a charging current for the capacitance, flows in that part.
The ground capacitance of the secondary coil 3 is limited to 300 PF or less, and leakage current is kept small to ensure safety.

Note that since the wound core 1 is insulated by the insulator 5,
The ground capacitance of the secondary coil 3 is the grounded primary coil 2
This value is calculated by adding the capacitance between the secondary coil 3 and the wound core 1 and between the wound iron core 1 and the primary coil 2, and then adding the capacitance between the secondary coil 3 and the wound core 1 and the primary coil 2 through the collar-shaped insulator 6.
and the capacitance between the primary coil 2.

In this case, since the -order coil and the secondary coil are arranged alternately, the direct capacitance between the -order coil and the secondary coil is small. Since most of the capacitance between the coils is
By increasing the thickness of the secondary coil 3, the ground capacitance of the secondary coil 3 becomes smaller, and the charging current of this capacitance, that is, the leakage current caused by a contact accident in the secondary wiring can be reduced.

As described above, according to the insulating transformer of this invention, the secondary coils and the secondary coils are arranged and wound alternately on the circular wound core whose outer periphery is covered with an insulating material, and A clamp that fixes the winding core is attached to the gap formed in the primary coil part where the leakage magnetic flux is minimized, and the capacitance between the -secondary coil and the secondary coil is Since the structure is configured to adjust the thickness of the insulator between each coil and the wound core, the capacitance between the secondary coil and the secondary coil can be kept small below the specified value, and the capacitance between the secondary coil and the secondary coil can be kept small. It is possible to minimize the leakage current when a live wire has a ground fault, thereby preventing electric shock accidents such as when it comes into contact with the human body.

In addition, since the coil has a large cooling area and good cooling efficiency, and the height of the transformer body can be reduced, it can be vertically embedded in a wall or the like.

[Brief explanation of the drawing]

The figures show an embodiment of this invention. Figure 1 is a plan view of the isolation transformer, Figure 2 is a sectional view taken along the line X-0-Y in Figure 1, and Figure 3 is the primary direction of the wound core in the circumferential direction. It is a graph diagram showing the distribution of leakage magnetic flux density B between the coil and the secondary coil. 1...Wound core, 2...-Next coil, 3
...Secondary coil, 4...Clamp, A
1 to A4...Gap.

Claims (1)

[Scope of utility model registration request] A gap formed in the primary coil portion where the leakage magnetic flux of the secondary coil is minimized by winding the secondary coil and the secondary coil alternately on a circular wound core whose outer periphery is covered with an insulating material. Attach a clamp to fix the wound core to the -
The capacitance between the secondary coil and the secondary coil is reduced by increasing the thickness of the insulator between the secondary coil and the secondary coil and between each coil and the winding core. Features: Isolation transformer.