GB2363004A - Transformer or inductor with flat magnetic core - Google Patents

Abstract

A transformer or inductor with a magnetic core M is designed for use in a confined space V by making the width of the core limb S at least three times the core packet height P. Also disclosed are a core with two or more parallel limbs having a distance between the extremities of the limbs of at least ten times the packet height, and a core with limbs at least four times the length of the packet height.

Description

2363004 Transformer or inductor The invention relates to a transformer or

an inductor (reactance or reactance coil).

is German and international standards specify certain structural shapes for the structure of transformers or inductors. Thus, for example, German DIN EN 60852-4, corresponding to IEC 60852-4, provides that the packet height of the magnetic circuits of inductors is to amount to 0.5 to 2 times the limb width of their core.

Sometimes, the installation space for transformers and inductors is severely restricted in particular in terms of the height; this applies in particular when transformers or inductors form parts of circuits which are to be accommodated in switchgear cabinets, and there possibly also in special cassettes. At the same time, the unit volume of such transformers and inductors is predetermined to a considerable extent by the electrical power to be converted, and in general can scarcely be reduced.

It is desirable to construct a transformer or an inductor in which at least one limb of a magnet core is provided with a winding in such a way that it can be accommodated in a restricted space.

The invention is defined in the independent claims, to which reference should now be made. Further advantageous features are detailed in the dependent claims.

According to preferred embodiments of the invention, the transformer/inductor is to be extremely flat in construction, in which case the space-requirement dimensions of the relevant standards are deliberately abandoned and instead, stipulations for the dimensioning of the magnet core that lie outside these standards are taken into account.

Advantageous embodiments and developments of the transformer in accordance with the invention or the inductor in accordance with the invention are presented in the subclaims.

is In the following, the invention is explained with the aid of an exemplary embodiment shown in the drawing. Figure 1 of the drawing shows an inductor constructed according to the invention and Figure 2 shows an inductor embodiment as would be provided by the skilled person heeding the cited standards for the arrangement in a restricted space.

Figure 2 shows an installation volume V available in practice for an inductor arrangement, in the form of a cuboid indicated with dash-dot lines. It can be seen that the space available for the inductor arrangement is very restricted in one dimension (height). In order to accommodate in the defined volume the inductances required for filtering electrical quantities, the skilled person has provided an inductor arrangement made up of, for example, six standard shaped relatively small inductors DI to DG, which are arranged side by side on a common carrier. The individual inductors are preferably connected electrically in paralliel. The inductors are constructed as three-phase inductors and each consist of a magnet core which is constructed for example, from (a packet of) coated laminations with windings arranged on the limbs of the magnet core. The magnet cores satisfy the demands of the relevant standards; the packet height of the magnet cores amounts to approximately twice the limb width, for example.

An inductor arrangement that satisfies the relevant standards, constructed in accordance with Figure 2, can admittedly be accommodated in a height restricted space, but is costly to manufacture, because it requires the production, assembly and interconnection of a plurality of separate inductors.

is By contrast, according to embodiments of the invention a transformer or an inductor is provided which satisfies the (new) space requirements demanded, as a result of the fact that, deviating from the stipulations of the relevant standards, it has a magnet core in which the packet height amounts, for example, to only one tenth to a maximum of about one third of the limb width. This leads to an extremely flat transformer/flat inductor, which, however, fully satisfies the electrical power requirements.

The arrangement in accordance with Figure 2, having a plurality of comparatively small inductors or transformers, can thus be replaced by an arrangement having only a single transformer or a single comparatively large inductor, which transformer or inductor satisfies the space requirements demanded.

The inductor constructed according to the invention, shown in Figure 1, is likewise constructed'as a threephase inductor and consists of a magnet core M preferably having three parallel limbs side by side and joined by end bars at each end and three windings/coils W each surrounding a limb of the magnet core. Such a transformer may have a total height measurement (in a direction at right angles to the limb length and to the is end bars/limb width) which is much less than (for example a quarter/fifth or less of) the measurements of the transformer magnet core in the other two directions. The magnet core is formed from preferably strip-shaped partial magnet bodies (or limbs), which are fixed in a suitable way. The limb width S of each of the magnet core is approximately three times as great as the packet height P of the magnet core, i.e. the limb height. The limb length is also much greater than the packet height, for example seven times the packet height measurement.

The inductor in accordance with the invention is constructed so as to be extremely flat (for example the distance between the sides of the external limbs may be times, for example more than four times, the height of the magnet core) and can be accommodated within the volume V available. In particular, it can be integrated in a suitable cassette-type housing, a plurality of which cassettes are to be accommodated, if appropriate, one above the other and/or side by side in a switchgear cabinet or suchlike.

Instead of the three-phase inductor presented in the exemplary embodiment, the invention can also advantageously be realised in single-phase inductors, likewise also in transformers, converters and transducers.

Even though the term "packet height" was used in the above description and the claims to describe the component in accordance with.the invention, the invention is not restricted to the use of laminated magnetic circuits, but instead also includes the use of amorphous, nano- crystalline sintered materials and ferritic materials of magnetic circuits constructed according to the dimensional stipulation of the invention.

In summary, according to embodiments of the invention, in order to accommodate a transformer or an inductor in a spatially restricted installation space at low height, the transformer/inductor is constructed so as to be particularly flat, the packet height of its magnet core amounting to only a fraction of the limb width of the magnet core. The spatial-requirement dimensions specified for transformers/inductors by the relevant standards are clearly abandoned in accordance with the invention.

Claims (7)

Claims

1. A transformer or inductor having a magnet core for flow-conduction, and at least one winding surrounding at least one limb of the magnet core, characterised in that the limb width of the magnet core amounts to at least approximately three times the packet height of the magnet core.

2. A transformer or inductor according to claim 1 wherein the limb width of the magnet core amounts to about three times to ten times the packet height of the magnet core.

3. A transformer or inductor wherein two or more parallel limbs are provided side by side to form the magnet core and the distance between the far sides of the external limbs is at least ten times the packet height.

4. A transformer or inductor wherein the length of the limbs is four or more times, preferably at least seven times the packet height

5. A transformer or inductor according to any of the preceding claims, characterised in that the transformer/inductor is constructed as a singlephase transformer/inductor or as a three-phase transformer/inductor.

6. A transformer or inductor according to any of the preceding claims, characterised in that it is integrated in a housing matched to its external dimensions.

7. A transformer or inductor according to claim 6, characterised in that a plurality of housings arranged one above the other and/or side by side form a common housing unit.

S. A transformer or inductor substantially according to the embodiment described in the description and/or shown in Figure 1.