DE29503048U1 - Three-phase transformer - Google Patents

Description

The present invention relates to a three-phase transformer, in particular a three-phase transformer with a core in the form of a circular ring, which is preferably composed of a package of magnetizable sheets and has three radial projections which protrude outwards from the circular ring at equal angular distances from one another, wherein a primary coil and a secondary coil can be applied to each of the radial projections.

A three-phase transformer of the aforementioned type is known from DE 43 10 199 A1. In the embodiment of the three-phase transformer described therein, the coils are wound onto the radial projections, with the radial projections being delimited on the outside by tangential fitting pieces that protrude laterally beyond the radial projections. In this way, the coils cannot slip off the radial projections. Winding the coils is only useful for relatively small transformers, whereas for larger transformers, sliding on fully wound coils is desirable. This is not possible in the embodiment described in DE 43 10 199 A1, since the tangential fitting pieces prevent this. Another disadvantage of such a three-phase transformer is the course of the magnetic field lines from one outer end of the radial projections to another outer end of the projections through the surrounding air. This results in large magnetic dispersions, which significantly reduces the effectiveness of the transformer.

The problem underlying the present invention is the creation of a three-phase transformer according to the preamble of claim 1, in which fully wound coils can be pushed onto the radial projections and in

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which also reduces magnetic scattering.

This is achieved according to the invention in that an outer circular ring made of a magnetizable material can be attached to the ends of the radial projections opposite the circular ring. By attaching this outer circular ring to the radial projections, the coils are prevented from slipping off the radial projections. Furthermore, the magnetic field lines are guided within the outer circular ring so that stray losses are largely avoided.

According to an alternative embodiment of the present invention, openings are provided in the radial projections in the area of the ends of the radial projections opposite the circular ring, into which locking pins can be inserted. These locking pins can extend above and below the radial projections, so that the coils cannot slip off the radial projections. On the other hand, the locking pins can be knocked out if, for example, a defective coil needs to be replaced.

Further features and advantages of the present invention will become clear from the following description of preferred embodiments with reference to the accompanying figures. Therein show

Fig. 1 is a plan view of an inventive

Three-phase transformer with radially arranged coils and a return ring; 10

Fig. 2 is an enlarged detail of the coil holder according to another embodiment of the present invention;

Fig. 3 a plan view of another embodiment

the three-phase transformer according to the invention;

Fig. 4 is a side view according to arrow IV in Fig.

As can be seen from Fig. 1 and 3, the three-phase transformer according to the invention comprises a circular ring 1, which is preferably composed of magnetizable sheets 2 stacked on top of one another (see Fig. 4), and three radial projections 3, which are arranged at equal angular intervals on the outside of the circular ring 1. A primary coil 4 and a secondary coil 5 are wound or plugged onto the radial projections 3, whereby the coils 4, 5 can be arranged one above the other, as in the embodiment in Fig. 1, or can be arranged next to one another, as in the embodiment according to Fig. 2.

In the embodiments according to Fig. 1 and Fig. 2, the three-phase transformer has a return ring 6, which after the coils 4, 5 have been pushed onto the radial

Projections 3 are pushed onto the three-phase transformer from above or from below and are fastened to the radial projections 3 using suitable fastening means (not shown). For smaller transformers, the return ring 6 can be welded to the projections 3. For larger transformers, for example, stainless steel strips can be placed radially around the rings 1, 6 and clamped, with the stainless steel strips being guided under the coils 4, 5 along the radial projections 3. The return ring 6 is also made of magnetizable material, with sheet metal packages also preferably being used.

According to the embodiment of the present invention shown in Fig. 3, the coils 4, 5 are held on the radial projections 3 not by means of a return ring 6, but by means of two locking pins 8 which are inserted vertically through the radial projections 3 in the outer edge area. As can be seen from Fig. 4, the locking pins 8 protrude slightly from the radial projections 3 at the top and bottom so that the coils 4, 5 cannot slip off the radial projections 3. In order not to impair the magnetic properties of the radial projections 3, these locking pins 8 can be made of non-magnetizable material such as aluminum or stainless steel.

Claims (3)

-i- Protection claims: 1. Three-phase transformer with a core in the form of a circular ring 1, which is preferably composed of a package of magnetizable sheets 2 and has three radial projections 3 which protrude outwards from the circular ring 1 at equal angular distances from one another, wherein a primary coil 4 and a secondary coil 5 can be applied to each of the radial projections 3, characterized in that an outer circular ring 6 made of a magnetizable material can be fastened to the ends of the radial projections 3 opposite the circular ring 1. 2. Three-phase transformer according to claim 1, characterized in that the outer circular ring 6 can be fastened to the radial projections 3 by means of screws 7. 3. Three-phase transformer according to the preamble of claim 1, characterized in that in the region of the ends of the radial projections 3 opposite the circular ring 1, openings are cut out in the radial projections 3 into which locking pins 8 can be inserted.