DE2121380A1 - Multi-phase current transformer for supplying thermal overcurrent tripping devices - Google Patents

Description

Patent attorneys

i / ipL-ing. Linen weaver

oipi.-ing. Carpenter · ".2121380

Munich 2, Rosental 7.
Tel. 2 60 39 89

Munich, April 30, 1971

Speaker & Schuh AG. ', Aarau (Switzerland)

Multi-phase current transformer for the supply of thermal overcurrent release devices

Addendum to patent (patent application P 19 40 810.7)

The subject of the main patent is a multi-phase current transformer for the supply of multi-phase thermal overcurrent release devices, consisting in each phase of at least one primary flow through which the main current flows and of at least one with the overcurrent release elements electrically conductively connected secondary winding, these windings being connected to one another via an iron core are magnetically coupled, as well as from fastening elements, The current transformer has a single iron core, common to all phases, with at least two windows, the connections of the primary and secondary windings of a phase only penetrate one window.

Among the embodiments dealt with in the main patent is already a current transformer is described in which the iron core consists of a comb-shaped, a yoke and four legs having part as well from a block-shaped butt attached to the support surfaces yoke provided with small elevations and the se-

secondary windings are attached to the cuboid yoke.

Such current transformers are only suitable for relatively small currents, because higher currents are due to the asymmetrical arrangement P254 209812/0876

the primary winding in the window in part of the iron core Saturation caused by leakage flux occurred, "as a result of which the measurement error becomes unacceptably large. The object of the invention is to provide the described current transformer for the management of high currents for the supply of the thermal overcurrent release devices portable To train measurement errors.

The stated object is achieved in that the iron core consists of four cuboid legs and two cuboid yokes that are butt-attached to them, and the secondary winding in each Phase is attached to the two cuboid yokes divided in half.

The invention is explained in more detail using an exemplary embodiment. Fig. 1 shows the longitudinal section of a three-phase current transformer. Fig. 2 is a cross section of the three-phase power converter.

The iron core 1 shown in Fig. 1, common for all three phases, has three windows 2. The iron core 1 consists of the four legs 4, 5, 6 and 7 and the two butt-attached to them ) cuboid, on the bearing surfaces with small ones Elevations 8 provided yokes 9. The iron core 1 is made of stamped transformer sheets by riveting. In order to enable a good support surface for the core parts, the support surfaces are ground before assembly. The yokes 9 are provided with small elevations on the support surfaces in order to obtain defined surfaces for surface grinding. The iron core 1 is held together by means of tension screws Io and transverse plates 23 and 12. The entire iron core 1 is screwed tight in the housing base 14 with screws 13. For pulling together the iron core parts and for fastening the entire iron core in the

lint he /
Housing part 14, the transverse plate 12 are provided with threaded holes.

The cross plates 23 have through holes for the lag screws Io on.

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The cover 24 of the housing made of insulating material is by means of Screws 25 attached to the transverse plate 23. For this purpose 23 threaded holes are provided in the transverse plate.

On the lower housing part V are foot pieces 17 (Fig. 2) attached, the one allow easy fastening of the current transformer.

The primary winding 18 of the current transformer consists of a single one Winding in each phase and is formed from a rectangular profile. The rectangular profile is in the recesses of the housing halves bO pinched so that it penetrates the window of the iron core symmetrically in the middle. There are two screws to prevent longitudinal displacement 19 (Fig. 2) secured. The primary winding 18 of the current transformer, which is formed from a rectangular profile, is covered with an insulating material Surrounding existing hose 2o in order to isolate it from the iron core 1.

The secondary windings are divided into two coil formers 22 in each phase and connected in series. The windings 26 have each bobbin 22 half the number of turns of the secondary winding of a phase. The bobbins 22 are on the cuboid yokes 9 pushed. The free connections of the secondary windings 26 are with the overcurrent release devices not shown in the figures electrically connected.

Due to the symmetrical arrangement of the primary and secondary windings In the window of the iron core, saturation of the iron core can be largely avoided at higher currents, which causes transmission errors of the current transformer remains below the desired limits at higher currents.

209812/0876

Claims (1)

Claim Multi-phase current transformer for the supply of multi-phase thermal Overcurrent release elements, consisting in each phase of at least one primary flow through which the main flow flows and of at least one electrically connected to the overcurrent release elements; a secondary winding, these windings being magnetically coupled to one another via an iron core, as well as from fastening elements, v / obei the current transformer has a single iron core common to all phases with at least two windows, v / obei the windings the primary and secondary windings of a phase penetrate only one window, characterized in that the iron core consists of four cuboid legs / and two butt attached to them 09) Qb) cuboid yokes, / consists and the secondary winding / in each phase is attached to the two cuboid yokes / divided in half. 209812/0876