US1501569A - Frequency-multiplier system - Google Patents

Description

July 15 1924 M. OSNO$ FREQUENCY MULTIPLJIER SYSTEM Flled Aug. 8, 1922 2 Sheets-Sheek l M. OSNOS REQUENCY MULTIPLIEI. SYSTEM 1 P Sheets-Sheet Filed Aug.

Patented July 15, 1924.

UNITED STATES MENDEL OSNOS, OF BERLIN, GERMANY, ASSIGNOR PATENT OFFICE.

TO GESELLSCHAFT F'll'R DRAH'I'LOSE TELEGRAPHIE M. B. H. HELLESCHES, 0F BERLIN S. W. 11, GERMANY, A CORPORA- TION OF GERMANY.

FREQUENCY-MULTIPLIER SYSTEM.

Application filed August 8, 1922. Serial No. 580,521.

T 0 all whom it may concern:

Be it known that I, MENDEL. OsNos, a citizen of Russia, residing at 12/13 Hallesches Ufer, Berlin, Germany, have invented certain new and useful Frequency-Molt} plier Systems, of which the following is a specification.

As evidenced by the work of Steinmetz- Theorie und Berechnungen der Wechselstromerscheinungen (Theory and calculations of phenomena of alternating currents), Berlin 1900, pages 118 to 123 inclusive, and German Patent, 286,531, it has heretofore been proposed to produce by means of highly saturated iron reactances in addition to a given basic frequency, still higher frequencies. In such a case, however, several frequencies of substantial amplitudes, arise simultaneously, whereas generally only one of them is desired.

The present invention makes it possible to produce the desired higher frequency in a particularly pure state. According to the invention, this isachieved by so choosing the size of the reactance and especially the ratio of the current feeding the reactance (or of the corrcspondin" ampere turns) to the saturation current or to the ampereturns serving to achieve the saturation point) that the time during which the magnetization of the reactance rises from zero to a sufficiently high value, i. e. to the socalled knee of the saturation curve, is to the durat on of one fourth period of the fundamental wave of the alternating current as 1 is to n, in which n denotes the desired multiple of frequency.

The operation of my invention will be understood from the following description when considered with the accompanying drawing, in which:

Fig. 1 shows a circuit by means of which my invention may be practiced.

Figs. 2, 3, 4. 5, 6, 7 and 8 are diagrams explaining the theory and operation of my invention.

Fig. 9 shows a modified circuit by means of which my invention may be practiced.

A reactance d, Fig. 1, may be fed from the genreator G over the circuit I with a basic frequency and may itself transmit the desired higher frequency to a correspondingly syntonized secondary circuit II.

In the circuit I there may be. arranged in series with the reactance (Z regulating devices such as variable syntonizing or tuning means, i. e. an inductance L in series with a capacity C, which causes the current produced by the generator to follow, so far as possible, a sine wave form. Furthermore, for relieving the generator from the wattless current or for purposes of stabilization, a device, such as a condenser D, may be used in parallel with the generator.

Since these regulating devices are used to keep the current flowing thru the reactance d sinusoidal and the counter E. M. F. set up by the reactance is non-sinusoidal (due to the phenomena on which this invention is based) the applied voltage across the reactance d is also non-sinusoidal. The generator G generates a sinusoidal voltage so, therefore, in order for the sum of the volt age drop across the reactance d and the voltage drop across the regulating devices should at all times be equal the generator voltage, the voltage drop across the regulating devices must be n0n-sinusoidal. The secondary circuit II fed with. the desired higher frequency may be connected, as shown, directly to the iron saturated reactance (i, for instance to certain intermediate windings or outer windings or coupled with the iron reactance inductively by means of .a secondary Winding W, Fig. 9.

In the following, it will first he assumed that the plant runs without load, in which case the current J sent by the machine into the iron reacrancrf'm'ay be assumed to be sine-shaped. If the iron reactanoe has no direct current ampereturns, its ampere turns are proportionate to its alternatin current and, if no consideration is tak n 0% the hysteresis, its magnetization B alters in accordance with its magnetization curve, Fig. 2. In consequence of this flux-variation, an electro-motive force is induced in the reactance which, in case the current is of sine-wave form, follows generally, as is well known, the course shown in Fig. 3, again assuming that the influence of hysteresis is not considered. The voltage curve according to Fig. 3 contains, in addition to the fundamental fre uency various higher harmonics of whic however, only a sin le one is needed as a useful wave. T is small.

tit)

the magnetization curve,

harmonic is. as a rule. not sufficiently pro nounced.

if conditions are chosen according to the invention. a voltage curve is obtained which has the desired.useful high harmonic very pronounced, while the others are almost completely suppressed. If, 'for instance, it is desired to use-the fifth harmonic for a useful wave. then. according to the invention, the conditions are so chosen that the volta e curve has the course shown in Fig. 5. T e characteristic feature of this curve is that at first it follows the course of a-negative half-way, the period 2t, of which constitutes fairly accurately the fifth part of half the period T of the first harmonic, and that with regard to shape it follows very closely the required sine-shaped half wave of the fifth harmonic. Then the curve alters very little for a long time, after which it forms a positive half-wave, which is of like period to the preceding negative halfwave and is apart from the latter by exactly% and th refore able to support it with regard to its effect.

For producing this voltage curve of a favourable shape, it is necessary that the field changes very quickly between points S, and S as is shown in Fig. 4, and that the voltage between the points S, S remains The field must alter very little dursay, the values of Fig. 4, between the Saturation ing this time, that is to points P, I- must be atstron (above the knee). The part ,-P of the magnetization curve, however, denotes a range of strong alteration, but of less magnetization. Thus the amounts of the induction B at the points P,-P, Fig. 4, must correSpond to the knee-points P, and P of the magnetization curve, Fig. 2, and the time i Figs. 4 and 5, must be the one during which the magnetization of the react- :umrises from zero to thel tnee value.

Now according to theaforegoing in the given case, that is, for the production of the fifth harmonic, 2t, must amount to one fifth of the time which is half of the basic period. Accordingly,

T T 2t,:- -=1: 5 or t.: =l:5. In an analogous manner, for the general case of an n-tlmes increase of frequency, the condition is obtained:

T t,: =1:n (l) Thus the condition for the iii-times increase of frequency can be expressed as follows: The time t, during which the magnetization of the reactance rises from zero to a sufliciently high value, that is, the kneeings.

point, must be to period of the first harmonic, that is. the basic frequency as 1: n.

The above condition also furnishes the formula for the relation between the momentary value i of the current which produces the saturation point. this current being sometimes briefly referred to hereafter as the saturation current, and the value of the amplitude J of the alternating current sent by the generator into the reactance. This is obvious from the vector diagram, Fig. (3, in which i is the momentary value of the current at the time t, with an amplitude J and a time period T. it is thus true:

i.=J,,, Sin 2w 2 Equating formula (2) with formula (1):

ll m Sm 2n From equation (3), the saturation current can be calculated if the desired multiple of frequency n and the maximum current flowing through the reactance are given, and from this current again the cross sectional area of the iron core of the reactance and the necessary number of turns in the windings of the reactance can be ascertained.

If reversedly, the dimensions of the iron core of the reactance, the number of turns in its windings, and thus also the saturation current are given, with equation (3) the' maximum current required for obtaining an n-times increase of frequency can be calculated.

The above described conditions also hold good approximately in cases when a load is put on or when the primary current departs slightly from the sineshape.

If the desired multiple n of the frequency is greater than 2, in the equation (3) the itself with sufficient approximation wheresine of can be replaced by the angle If the iron reactance is used without direct current magnetization as in the aforede scribed example, the currents i, and J flow generally through one and the same Wind- In case, however, direct current mag netization is employed as illustrated in Fig. 9, the saturation current is caused to flow through windings K different from the alternatlng current windings. in this case, in place of the currents the corresponding ampere turns are put into the equation (3) or (4). Then in these equations, i. and J denote ampere turns.

If the iron reactance be magnetized by means of direct current an even. for example, a six-field increase of frequency is to be produced. If the abscissa in Fig. 2 now represents the direct current ampere turns which produce the necessary saturation of the reactance, the value of the alternating current ampere turns can be calculated from the formula (3) or (4) respectively and for the reactance a fie1d-curve with the momenta course of the induction according to Fig.1 is obtained from which results the voltage curve according to Fig. 8.

As the alternating current at the knee points is in this case equal to zero, the length a, s in Fig. 7 re resents the time between two passages o the alternating current through zero, i. e. g which denotes half of the basic period. The points 0 of the curve, Fig. 7, correspond to the points at which the direct currentand alternating current ampere turns neutralize each other so that the induction is zero, and the points S represent those moments in which the induction passes through the knee-values P of the negative part of the magnetization curve. The periods S S=2t, are again the periods of the intensive alteration of the induction, the periods a, s and 8,, a, being the periods of small alteration.

The time 26, is in Fig. 8 one sixth of the time 5 (corresponding to the desired sixfold frequency) and the positive half-wave of a sixfold frequency is moved to the right in such a manner with regard to the middle position between two negative half waves of a sixfold frequency that the positive and negative half-waves support each other with regard to their effect on the started oscillation of a sixfold frequency.

This shows that also in this case the condition stated above for the reactance without the direct current excitation is fulfilled, as also here the time OS=t,, Fig. 7, during which the flux rises from zero to a sufiiciently great value to saturate the core and amounts to one nth, that is, in the case assumed to one sixth part of the time I claim as my invention:

1. An alternating current system comprising a highly saturated iron reactance, a secondary circuit for withdrawing current from the reactance and means for supplying current to the reactance, the reactance being of such size and the means for supplying the current to the reactance being so constituted that the time required for the magnetization of the reactance to rise from zero to the knee of the saturation curve is to the time of one-fourth period of the basic wave of the alternatingcurrent system substantially as 1 is to the desired multiple of the basicfrequency, substantially as described.

2. An alternating current system for increasing frequency by means of a highly saturated iron reactance, which comprises a reactance of such size and means for supplying current to the reactance in such ratio that the time required for the magnetization of the reactance to rise from zero to the so-called knee of the saturation curve is to the time of one-fourth period of the basic wave of the alternating current system substantially as 1 is to the desired multiple of the basic frequency, substantially as described.

3. An alternating current system for increasing frequency by means of a highly saturated reactance, comprisin a reactance with an alternating current winding and a direct current winding, and means whereby the value of the magnetization caused by the direct current winding is at the knee of the magnetization curve, and means whereby the ratio of the time required'for the magnetization to change from Zero to the knee of the magnetization curve is to the time of one fourth of the period of the basic alternating current wave substantially as one is to the desired multiple frequency, and means for utilizing said multiple frequency.

In testimony whereof I have signed mv name to this specification.

MENDEL OSNOS

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