DE2844618A1 - Low copper content meander core for current transformer - uses multiple windings running forward and backward in axial direction of primary winding and arranged in group-parallel configuration - Google Patents

Abstract

To reduce the copper content associated with current transformers using the more conventional ring or annular cores, and to avoid the pitfalls associated with winding connections, partic. with open secondaries the proposed meaniter type core (1) has multiple windings (2)that run forwards and backwards in the axial direction(4) of the primary winding. The windings moreover, are specifically connected in group-wise parallel configuration, amid the core(1) itself has an air-gap. Copper foil or short-circuit windings are arranged in the gaps (3) between the core paths.

Description

Current transformer meander core

The required copper application of current transformer cores can - depending according to the number of ampere-turns and the permitted dimensions - spatial or thermal Create difficulties and set limits for the feasibility at all. So e.g. requires a toroidal core with e.g. 70 cm clear diameter at z. B. 50,000 A nominal current a copper application of approx.

23 cm, which may require water cooling, in particular at room temperatures above e.g. 90 C.

There are dangers associated with toroidal cores with a large winding order to interturn faults, especially with an open secondary circuit.

According to the invention it is proposed that the winding order thereby to reduce considerably so that the iron path of the core is artificially lengthened, by repeating the core in a meandering shape in the primary conductor axial direction (4, Fig. 1 running forwards and backwards, is executed (1, Fig. 1).

The mean winding length is corresponding to the smaller winding order and thus the heat loss and the internal burden of the converter are reduced considerably. at the internal burden is i. a. determining the iron cross-section, so that the mean winding length is reduced even further. There is also the copper cross-section can become smaller for thermal reasons, there will be a further reduction of the winding order.

By connecting any diagonal winding groups in parallel the desired balancing effect against the influence of neighboring conductors can be achieved.

As a support frame for the core structure, for. B. 2 end rings with indentations, in which the individual core sections (Fig. 1) engage, serve.

If necessary, the core can have air gaps for the purpose of linearization. Furthermore, 2 or more cores can be arranged next to one another (axially or radially).

The core can be a ring or a rectangular core, made up of individual ones Box core sections or consist of a tape package on which the secondary windings (similar to Fig. 1) are lined up. To ward off the stray field in the core gaps (3) Pieces of sheet copper or short-circuited windings can be used in a known manner to be ordered.

The manufacturing costs result from the reduced copper weight, from the costs for the machine winding of the coils, the iron core and the box core Costs.

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Claims (1)

Claims Claim (current transformer d. G. That the core (1, Fig. 1) in Meander shape with a corresponding number of windings (2) in the primary conductor axis direction run forward and backward, is executed. Claim 2: Current transformer according to Claim 1 d. g. that windings in groups can be connected in parallel. Claim 3: Current transformer according to Claims 1 and 2 d. g. that the core Has air gaps. Claim 4 current transformer according to claims 1 to d. G. that copper sheets or short-circuit windings are arranged in the core gaps (3). Claim 5: Current transformer according to Claims 1 to 4 d. g.> that 2 end rings serve with depressions to hold the core sections.