JPH0467607A - Butt type transformer - Google Patents

Abstract

PURPOSE:To sharply reduce the magnetic resistance of a butt-together aperture part, and to make it possible to sharply reduce a no-load exciting current, copper loss in other words, by a method wherein magnetic powder is contained in the resin layer located in a butt-together aperture part. CONSTITUTION:A butt type transformer is a three-phase transformer, for example, and it is equipped with coils 3a to 3c to be wound on laminated cores 1 and 2, and a resin layer 5 to be injected into the butt aperture part 4 located between the laminated cores 1 and 2. The above-mentioned resin layer 5 contains pure iron powder, having high permeability, and high ferrosilicon powder with a high mixture ratio. As a result, a no-load exciting current can be sharply reduced in this transformer even when it is idling, and as a result, the power loss in idling is reduced, and the.overheating of the butt type transformer can be prevented.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a butt type transformer.

[Prior Art] Utility Model Application No. 55-178246 discloses attaching a step-up transformer to a vehicle alternator in order to supply power to a high voltage load.

For the above-mentioned small-sized transformers, a butted type transformer in which laminated cores are butted to form a closed magnetic circuit is advantageous in manufacturing.

In addition, in such butt type transformers, it is customary to apply varnish or resin mold to the inside of the butt gap and other parts in order to fix each laminated core, improve insulation, and dampen vibrations. be.

[Problem to be solved by the invention] However, in such small butt-type transformers, it is important to reduce volume and weight from the viewpoint of storage, etc. (up to a level limited by However, a decrease in the amount of iron increases the magnetic resistance of the laminated core. At the same time, the cross-sectional area of the abutment gap is also reduced, resulting in an increase in the magnetic resistance of the abutment gap. Since such an increase in magnetic resistance causes a decrease in magnetic flux, the no-load excitation current increases, resulting in a significant increase in copper loss. Such an increase in copper loss becomes a major obstacle in application to the step-up transformer for the above-mentioned vehicle alternator.

That is, the frequency of the vehicle alternator is proportional to fluctuations in engine speed, and the frequency decreases during idle rotation, so the no-load excitation current during idle rotation is large. Therefore, if a small butt type transformer, which inherently has a large no-load excitation current, is used as the step-up transformer, the no-load excitation current will greatly increase during idle rotation due to the synergistic effect of both.
This results in an increase in the power generation load during idle rotation. It may also lead to overheating of the butt type transformer.

The present invention has been made in view of the above problems, and an object to be solved is to provide a butt type transformer capable of reducing the no-load excitation current.

[Means for Solving the Problems] The butt type transformer of the present invention comprises a closed magnetic circuit formed by abutting a plurality of laminated cores, and a resin layer injected into the gap between the abutments between the plurality of laminated cores. The butt type transformer is characterized in that the resin layer within the butt gap contains magnetic powder.

[Operation and Effects of the Invention] In the above-described butt-type transformer of the present invention, since the resin layer in the butt gap contains magnetic powder, the magnetic resistance in the butt gap can be significantly reduced. Moreover, it is possible to significantly reduce the no-load excitation current, that is, the copper loss.

[Embodiment] An embodiment of the butt type transformer of the present invention will be described with reference to FIG.

This butt type transformer is a three-phase transformer, and includes a pair of laminated cores 1.2 and a coil 3 wound around the laminated cores 1.2.
a to 3C, and a resin layer 5 injected into the butt gap 4 between the laminated cores 1.2.

The laminated core 1.2 is made by laminating silicon steel plates of the same shape, and has three-phase projecting pillars 11 extending in the same direction parallel to each other.
-13 and 21-23.

These pillar parts 11 to 13 and 21 to 23 are individually butted against each other to form a three-phase open magnetic circuit.

A resin bobbin 6a is fitted into the pair of protrusions 11.21, and a coil 3a consisting of primary and secondary windings for the first phase is wound around the resin bobbin 6a.

Similarly, a resin bobbin 6b is fitted into the pair of protruding pillars 12.22, and a coil 3b consisting of primary and secondary windings for the second phase is wound around the resin bobbin 6b.

Further, a resin bobbin 6C is fitted into the pair of protruding pillars 13.23, and a coil 3G consisting of primary and secondary windings for the third phase is wound around the resin bobbin 6C.

The resin layer 5 injected into the butt gap 4 between the respective projecting pillars 11 to 13 and 21 to 23 contains pure iron powder with high magnetic permeability and high silicon iron powder at a high mixing ratio. The resin layer 5 is formed by applying an epoxy resin liquid containing magnetic powder to each abutting surface of each of the protruding pillars 11 to 13 and 21 to 23, and polymerizing the epoxy resin liquid after the cores are abutted.

A groove 4a is provided on the inner surface of the resin bobbins 6a to 6C facing the butt gap 4. The groove 4a is for storing the epoxy resin liquid leaking from the butt gap 4 after the cores are butted.

The laminated cores 1.2 that have been butted together in this manner are assembled by wrapping a thin steel band 7 around them and tightening them with a tool 8.

The transformer, which is assembled like a mouth, is then coated with varnish or molded, and finally completed.

Figure 2 shows an example of the test results. When the width of the abutment gap 4 is 60 μm and it is not filled with magnetic powder, when the width of the abutment gap 4 is 60 μm and it is filled with magnetic powder, and when the width of the abutment gap 40 is made almost 0 μm by precision polishing (
Therefore, if the three-phase AC frequency is 400 Hz (for example, the engine speed is about 156 ORPM), the gap length is 60 μm.
The excitation current is approximately 5A, and when filled with fine powder magnetic material, the excitation current becomes approximately 1.5A, which can be reduced to approximately 1/3, and the no-load power loss can be reduced to approximately 1/9. Ta.

In this example, a resin liquid containing magnetic powder was injected, but only magnetic powder may be injected. Even in this case, if you apply varnish or resin mold after filling,
A resin layer is formed in the butt gap 4.

FIG. 3 shows a vehicle power generation device using the butt type transformer of this embodiment.

This power generation device consists of a three-phase alternating current generator 21 with a full-wave rectifier.
The three-phase alternator 21 charges the battery 22 with a full-wave rectified voltage. The terminal voltage of the battery 22 is input to the regulator 23, and the regulator 23 controls the field coil 24 of the three-phase alternating current generator 21 to control the generated voltage.

Further, the three-phase AC voltage of the three-phase AC generator 21 is boosted by a step-up transformer 25, and then full-wave rectified by a full-wave rectifier 26.
It is then supplied to the high voltage load 27. 28 is a smoothing capacitor.

(Effects of Example) As explained above, the butt type transformer of this example, which is used as a step-up transformer for a vehicle alternator, can significantly reduce the no-load excitation current compared to the conventional one even during idle rotation. As a result, power loss during idle rotation is reduced and overheating of the butt type transformer is prevented.

In particular, although the power generated by a vehicle generator suddenly decreases as the engine speed decreases, the electrical load such as air conditioning remains almost constant regardless of the decrease in engine speed. The reduction in power loss during operation is possible without the need for increasing the size of the butt type transformer, which is extremely advantageous in vehicle applications.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing one embodiment of the butt type transformer of the present invention, Figure 2 is a characteristic diagram showing its no-load excitation current characteristics, and Figure 3 is an application of the butt type transformer of Figure 1. FIG. 2 is an equivalent circuit diagram of an embodiment of a vehicle power generation device. 1.2... Laminated iron core 4... Butt gap portion 5... Resin layer containing magnetic powder

Claims (1)

[Claims] In a butt type transformer in which a closed magnetic circuit is configured by butting a plurality of laminated cores, and a resin layer is injected into a butt gap between the plurality of laminated cores, the resin layer in the butt gap contains magnetic powder. A butt type transformer characterized by: