GB2276986A

GB2276986A - Choke

Info

Publication number: GB2276986A
Application number: GB9406349A
Authority: GB
Inventors: Peter Aufleger; Gerd Flaemig
Original assignee: Siemens Matsushita Components GmbH and Co KG
Current assignee: TDK Electronics AG
Priority date: 1993-04-05
Filing date: 1994-03-30
Publication date: 1994-10-12
Anticipated expiration: 2014-03-30
Also published as: DE4311126C2; FR2703819B1; FR2703819A1; CH688116A5; GB2276986B; DE4311126A1; GB9406349D0

Description

k 2276986 MULTIPLE LINE CHOKE The invention relates to a multiple line

choke, and more particularly to a current-compensated multiple line choke. 5 High- grade electromagnetic compatibility f ilters for plants, screened rooms and systems are designed for interference frequencies of up to several GHz and high rated currents of up to thousands of Amps. For this purpose it is necessary that the chokes used in the filters should exhibit a low d.c. resistance for symmetrical and asymmetrical interference suppression with a very high level of attenuation, resulting in a low voltage drop and thus a low power loss. It is also desirable to produce chokes of small constructional size and low weight which can be connected in cascade, by having a modular design.

Current-compensated chokes for symmetrical and asymmetrical interference suppression are known having a wound construction, and rod-core chokes are known for symmetrical interference suppression. These have commonly been used in filters, and the chokes must be designed with consideration of the rated current. The wound construction, as well as the necessary number of electrical connections of the components for symmetrical and asymmetrical interference suppression, increases the d.c. resistance of the choke. This resistance constitutes an important criterion with regard to the mechanical construction and electrical properties of the choke.

In order to achieve higher inductance, more turns are required, and this presents a higher ohmic resistance and, at the same current loading or at rated current, a higher voltage drop, and therefore a higher power loss, which is typically dissipated as heat. A larger number of turns also adversely affects the current saturation behaviour of the chokes.

According to the present invention, there is provided a multiple line choke, having a plurality of electric conductors, comprising a component for asymmetrical interference suppression comprising a core through which the electric conductors pass, and a component for symmetrical interference suppression comprising a core applied to one of the electric conductors.

This provides a multiple line choke of compact construction.

Preferably, the component for symmetrical interference suppression comprises a plurality of cores, each conductor being at least partially surrounded by a respective one of the cores.

The electric conductors can either have the form of flexible conductors, solid conductors or hollow conductors.

It is preferred that the choke can be connected in cascade with at least one further electric component without additional outlay, for which purpose end regions of the electric conductors may be provided with outer and/or inner threads.

For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: - Fig. 1 show a current-compensated multiple line choke; Fig. 2 is a sectional diagram of the choke shown in Fig. 1; and Fig. 3 is a circuit diagram of the choke shown in Fig. 1.

Fig. 1 illustrates a choke comprising four electric conductors 2 which are referenced Ll, L2, L3 and N. The electric conductors 2 extend inside two cores 1 of very high permeability, whereby a current-compensated choke with one turn is formed. This results in the component U for the asymmetrical interference suppression. The electric conductors 2 are constructed so as to be insulated both in relation to the highly permeable cores 1 and also in relation to one another and other conductive materials. For this purpose, for example, the conductors 2 are spaced by means of holders consisting of insulating material. By virtue of a suitable construction of the holders improved short-circuiting behaviour of the overall choke is achieved.

Outside the component U for asymmetrical interference suppression, the electric conductors 2 are suitably shaped in the zone 4, in order to facilitate the application of cores 5 for symmetrical interference suppression.

In Fig. 2, which illustrates the section shown in Fig. 1 in the plane IIII, it can be seen that the electric conductors Ll, L2, L3, N are formed in such manner that the cores 5 can be applied to the individual electric conductors. It can also be seen from Fig. 2 that the individual electric conductors are insulated from one another by a cross-shaped insulation member 3.

In the end regions 6 of the electric conductors 2 there are arranged outer and/or inner threads (not shown in Fig. 1) which can be used for the attachment of the input and output lines of a further choke or of one or more multiple line feed-through capacitors.

The design of the choke enables the use of conductors 2 with large crosssectional dimensions. This, coupled with a reduction in the number of connection points, serves to minimise the ohmic resistance. The voltage drop, and thus also the power loss, are therefore reduced to a minimum by using the choke shown in the drawings.

The construction of the contacts gives rise to material savings so that the choke can be constructed in a space-saving fashion and with low weight.

By adding or removing cores the inductance of the choke can be adapted to different requirements, for example attenuation requirements.

The current-carrying conductors 2 are composed of a suitable material, and it is possible to use both rigid and flexible conductors as well as hollow conductors such as tubular conductors. The shape of the conductors 2 is dependent upon the use of the choke and the circuits into which the choke is designed to be fitted.

In addition to the embodiment shown in the Figures, of a choke comprising four electric conductors, other forms of choke comprising a different number of electric conductors are also possible, although the invention requires the choke to comprise a minimum of two conductors.

Claims

1. A multiple line choke, having a plurality of electric conductors, comprising a component for asymmetrical interference suppression comprising a core through which the electric conductors pass, and a component for symmetrical interference suppression comprising an individual core applied to one of the electric conductors.

2. A multiple line choke as claimed in claim 1, in which the component for symmetrical interference suppression comprises a plurality of individual cores, each conductor being at least partially surrounded by a respective one of the individual cores.

3. A multiple line choke as claimed in claim 1 or 2, in which the electric conductors comprise solid conductors.

4. A multiple line choke as claimed in claim 1 or 2, in which the electric conductors are flexible.

5. A multiple line choke as claimed in claim 1 or 2, in which the electric conductors are hollow.

6. A multiple line choke as claimed in one of claims 1 to 5 in which the conductors have end terminals, which enable the choke to be connected in cascade with at least one further electric component.

7. A multiple line choke as claimed in claim 6, in which the end terminals of the electric conductors are provided with outer and/or inner threads.

8. A multiple line choke as claimed in any preceding claim, in which the choke is a current- compensated choke.

9. A multiple line choke substantially as described herein with reference to, and as shown in, the accompanying drawings.