DE1090348B - Pre-magnetized ferromagnetic core for modulators and variometers - Google Patents

Description

GERMAN

The invention relates to a pre-magnetized ferromagnetic core for modulators and Variometer with an excitation circuit and a circuit to be controlled, which consists of different ferrite parts Permeability and different temperature coefficient of permeability exists.

Such a variometer is known. The excitation system of this variometer consists of one Ferrite saturation as high as possible, for example from a manganese ferrite, whereas the ferrite core of the to be controlled circle made of a material of high coil quality, for example made of a nickel ferrite, consists.

It is also known to use such cores as the materials for the core parts of the excitation system on the one hand and that of the system to be controlled on the other hand to be selected so that a smallest S is expensive performance at the highest possible temperature constancy.

The object of the invention is also the temperature coefficient the "permeability in the circle to be controlled practically to disappear and In addition, to keep the pre-magnetization power as small as possible.

In contrast to the prior art, in which - as stated - on the high saturation of the core material of the excitation circuit and the high "quality" of the core material in the system to be controlled the invention is based on the following findings:

The permeability of relatively low-permeability substances decreases relatively weakly with increasing bias; the permeability of relatively highly permeable substances decreases relatively sharply with increasing bias. This is shown schematically in FIG. 1. The pre-magnetization is plotted on the abscissa in ampere-turns (AW), on the ordinate the ratio of the permeability in the pre-magnetization to the permeability of the non-pre-magnetized material. The curve drawn as a closed line shows the permeability curve of a relatively low-permeability substance (e.g. nickel-manganese-zinc ferrite with a permeability without premagnetization of about 300). The dashed curve shows the permeability curve of a relatively highly permeable substance (eg manganese - zinc ferrite with a permeability without premagnetization of around 700). It can be seen that in the case of the premagnetization X the permeability of the low-permeability substance has decreased comparatively weakly, whereas the permeability of the high-permeability substance has decreased comparatively strongly.

For comparison with this, FIG. 2 shows the course of the pre-magnetized ferromagnetic! ·
Core for modulators and variometers

Applicant:
Siemens & Halske Aktiengesellschaft,

Berlin and Munich,
Munich 2, Wittelsbacherplatz 2

Paul Gottschalt and Gustav Roespel, Munich,
has been named as the inventor

Temperature coefficients of these substances are shown. With a low bias, the temperature coefficient T _{k is} greater than zero in both cases (this applies to almost all ferrites)

"5" higher permeability, however, strongly.

In order to achieve a wide permeability range depending on the bias, is according to Fig. 1, the use of a relatively highly permeable substance advantageous to a lower To achieve temperature coefficients, the use of a relatively low-permeability substance (Fig. 2). Now it is not necessary that the temperature coefficient in the excitation circuit practically disappears, but only in the circle to be controlled.

One can therefore take advantage of the large permeability range depending on the bias and the low temperature coefficient in the circuit to be controlled thereby jointly according to the invention achieve that the majority of the excitation circuit and the smaller part of the one to be controlled Circle made of a ferrite of high permeability and negative temperature coefficient for the premagnetization the permeability and the remaining parts from a ferrite of low permeability and in the bias produces positive temperature coefficient of permeability, these ferrite parts from such substances exist and are arranged such that the temperature coefficient of permeability practically disappears in the circle to be controlled.

This rule allows for a variety of embodiments, some of which seem particularly useful are described below:

In Fig. 3, a modulator is shown, which essentially - as known per se - the shape of a

009 610/326

Has ring 30 with a hole 31 in the annular bead. The ring consists of a part 32 lower Permeability and positive temperature coefficient at the premagnetization and a part 33 higher Permeability and the negative temperature coefficient of permeability during premagnetization. By the hole 31 is to be controlled high-frequency winding out to the opposite leg the Excitation winding 34.

FIG. 4 shows another embodiment according to FIG. 3. The ferrite part with a positive temperature coefficient is denoted by 42, the other by 43. The excitation winding and the winding to be controlled are the Omitted for the sake of clarity.

A geometrically particularly favorable division of the core parts is shown in FIG. 5. Here are the low permeability Parts 63, 64 sintered together with the highly permeable parts 65, 66, as in the Production of combination cores from various solid materials is known per se. 2c

Fig. 6 shows a gear rim modulator designed according to the invention, the left half in view, the right half in section. The pot 70 of the modulator is made of highly permeable ferrite, the lid of low permeability ferrite. The individual windings to be controlled (e.g. 71) are in a manner known per se attached to two teeth 72, 73 of a toothed ring attaching to the edge of the base, so that all Windings are excited by a single excitation winding, which is housed in the interior 74 can.

Claims (5)

Patent claims: to be controlled circle, characterized in that the majority of the excitation circuit and the Smaller part of the circuit to be controlled from a ferrite part of high permeability and with the premagnetization negative temperature coefficient of permeability and the remaining parts from a ferrite part of low permeability and in the bias positive temperature coefficient of permeability exist, these ferrite parts consist of such substances and are arranged such that the temperature coefficient of Permeability in the circle to be controlled practically disappears. 2. Core according to claim 1, characterized in that it has the - per se known ■ - · shape has a ring, the annular bead is provided with a hole. 3. Core according to claim 2, characterized in that part of the ring from the said high permeability ferrite and the other part of the ring made of said ferrite low permeability. 4. Core according to claim 1, characterized in that the core parts are made of the ferrite materials different permeability are sintered together. 5. Core according to claim 1, characterized in that it - · as known - as a closed Pot core is formed and that the lid of the pot is attached to its edge Has ring gear that carries a plurality of circles to be controlled. 1. Pre-magnetized, made of ferrite parts, documents considered: different permeability and different 35 German Patent No. 951 819; Temperature coefficients of permeability in German Auslegeschrift N 7434 VIIIc / 21g (existing ferromagnetic core for modulators announced on October 25, 1956); and variometer with an excitation circuit and a "frequency", January 1957, pp. 19 to 27. 1 sheet of drawings © 009 610/326!).