US1985635A - Regulating system - Google Patents

Description

Dec. 25, 1934. w. K FLEWNG 1,985,635

REGULAT ING SYSTEM Original Filed April 28, 1928 111+: be M n 2, HQ 4' v I? 10 f9 F76 J W T b5 1: 7 1 J INVENTOR. h gflz c A TTORNE Y.

Patented Dec. 25, 1934 UNITED STATES 3,985,635 REGULATING SYSTEM Wilfred K. Fleming,

Qambridge, Mass, assignor,

by mesne assignments, to Raytheon Manufacturing Company, of Delaware Newton, Mesa, a corporation Application April .28, 31928,. Serial No. 273,719

Renewed Octoher 19,

8 Claims.

My invention relates to an electrical regulating system and more specifically to a power transformation system whereby variations of input voltage over a wide range of limits do not affect the voltage output in any substantial degree.

The recent developments of radio receiving systems have resulted in a demand for means for supplying the filament and plate circuits of vacuum tubes from the ordinary house current mains. As is well known, the thermionic tubes used in such sets require that the power delivered to them be of substantially constant and invariable voltage. distribution of alternating current for domestic purposes, it is practically impossible for the voltage of the house circuit to be constant throughout the day or to be equal to the voltage otthe circuit in another house. The load variations through the day result in line variations. The 2 position of the particular house circuit with respect to the supply transformer, as well as the position of the supply transformer with respect to the high tension mains, results in a voltage variation which not only occurs through the day in one particular spot, but which also occurs among a number of spots at one particular time The ordinary means for translating the alterhating current of the mains into substantially direct current for use in a radio receiving 39 comprises atransformer, a rectifier in secondary circuit, and means for filtering out and smooth= ing out the ripples in the rectified current. It will readily be seen that as the line voltage va-= rice, the final rectified voltage will vary and thi less compensating means at the radio receiving set are used, the tubes will be operated more or less haphazardly. Such haphazard tube operation is very bad on the life of the tube. It the filaments of the tubes are operated in such a manner, they will be burned out or stripped of their coating depending upon whether the filement is overloaded or underloaded. If the plate circuit varies too much, a great plate voltage over=- load-will strip the filament or paralyze the tube.

My invention aims at overcoming the variations in secondary voltage, irrespective of how the prl-= many line voltage may vary within reasonablywide limits. Although I have described my in= vention with reference to a vacuum tube supply system, it is to be clearly understood that my invention is independent of this and may be used wherever a constant voltage which is to be obtained from a variable voltage is required. Although the variations may be fast, it will readily be understood that the variations might just as well be over a period of days or even weeks and in fact, the supply voltage need not necessarily vary at all and can very well be dilferent from what is ordinarily taken as the average.

In the broader aspects of the invention, the

Under the present methods of voltage supply is divided up into two vector quantitles. The magnitude of one of these vector quantities is kept substantially constant and this quantity is the one that is actually used. The other vector quantity is allowed to vary although its magnitude, too, may be kept constant. In either case, this second vector quantity, whether variable or constant, may be used or discarded. The angle between the two vectors is allowed to vary. in this way, the supply voltage which, of course, represents the resultant vector is broken up into the above two vectors. The variable resultant has as its counterpart in the components, the variable phase angle and perhaps one variable vector, the other remaining substantially constant.

y invent n is an improvement on the inventhe subject of my application entitled Regulating systein, Serial No. 267,402, filed April 1928, and assigned to the same assignee this case.

In the application mentioned, the invention broadly comprises a system for accomplishing substantially same results as my invention does. The means for accomplishing coniprises in general a transformer, the primary of which in series with a reactance is either predominantly capacitative or inductive.

the

also an inductance as a choke or transformer used in connection This choke or transreactance is capacitative, then there is former nae a large capacity used with it so that combination is capacitative. The substantial constancy of voltage may be obtained either at the urinals or the inductive or capacitative part of .e system. In any event, the inductance which e either a choke or a transformer, which is of the capacitative portion of the system, i operated preferably at the upper bend or the magnetization curve. This is done in order to take advantage of the very large variation of inductance with small variation oi impressed voltage. 1

The capacity may be assumed to be constant for all practical purposes. The result is, therefore, that capacitative portion of the system a small change in voltage across the terminals oil that portion of the system will result in a current change which will result in a or the value of inductance and hence the effec tive react'ance of thecapacitative portion of the system is materially changed, thus resulting in a phase displacement between current and voltage.

Of course it is to be understood that the choke might be used in the'inductive portion of the system and the transformer be part of the capacitative portion or" the system.

' By actual measurement the voltage across each portion of the system has been measured and since the actual numerical values do not great change by operating as the cross sections of the other two legs.

differ very much with the variation in line voltage, the only logical conclusion is that the phase angle is changed. The inductance of the capacitative portion of the system need not of necessity be operated at that portion of the curve and may actually be operated on any non-linear part of the magnetization curve, but best-results are obtained stated. The inductive portion of the system may or may not be. operated at the same portion of magnetization curve.

To make a device embodying a regulating system as above described, commercially practical, it must be compact, must have as little material therein as possible and be efficient. In general, my improvement consists in winding all the necessary coils on one core. I also make use of an auto transformer, rather than a transformer with two separate windings to save materials and space. In this way, the wire of the autotransformer carries both primary and secondary currents, which of course, are in opposition and thus less copper is required than would ordinarily be the case. Since the core is operated at a high magnetic intensity by at least one of the inductive elements of the system, itcan readily be seen that there will be considerable heat losses in the core from that fact alone. By combinin all inductance elements on one core, I have applied the same heat losses to a greater massthat is, a greater core in this instance-withthe result that the entire core will run much cooler,

especially at high loads.

as is well known, the-primary and secondary currents in an autptransformer are approximately 180 out of phase with each other. The result will be that that portion of the wire which carries both secondary and primary currents will only have the difference between the currents.- This means that with less current flowing through a considerable portion of the transformer, the resistance losses which are transformed into heat will be much less than would be the case were there two separate coils. Hence, by my improvement in combining all the inductance elements on one core, I have reduced the current losses and the heating effect therefrom and have distributed the heat losses in the magnetic core over a much greater mass of material.

In additionto the above-what might be termed technical advantages-the device as a whole becomes much more compact, requires less material and is considerably cheaper than the system of the application abover Referring to the above in general, I carry out my invention by providing a three legged core, the central leg'having a cross section approximately equal to the sum of The outside legs may be of substantially equal cross section but need not be so if not desirable. On one leg, I wind a coil which is tapped at an intermediate portion thereof. The entire coil represents the secondary of the autotransformer while a smaller portion thereof comprises the primary of the autotransformen. On the other leg of the core, I provide primary and secondary coils of a transformer. The first coil and primary of the transformer are connected in series and have the line current flowing through them. By suitably connecting a capacity in the circuit, I make one of the inductance elements part of a capacitative load in which the inductance changes greatly with a comparatively small change of' applied potential.

Referring to the drawing;

Figure 1. shows one form of my invention,

0 to the outer end of '8 and end of the primary 4.

I a filter 16 shown here Figure 2 is a modification,

Figure 3 is a diagrammatic vention,

Figures 4 and 5 are to Figure 3,

Figure 6 is a vector diagram of the resultants obtained from Figures 4 and 5.

Referring to Figure 1, there is shown the three legged core 30 having the end legs 31 and 32 preferably of substantially equal cross section and the central leg 33 equal to the cross sections of the other two. On leg 31 is wound a coil which is tapped at 8, forming coils 2 and 3. L 0n the other leg are wound primary 4 and secondary 10 of a transformer. Conductor 9 connects outer end of coil 2 to the primary 4. The other end of primary 4 is connected through a condenser coil 8 on coil 1 is more or less related to the capacity of condenser C and in general, the greater the capacity of condenser C, the nearer to the condenser tap 8-approaches. Across tap 8 and outer end of coil 3 is connected 9. variable resistance R. The line supply 6 and 'I is connected to tap The secondary 10 of the transformer, as is usual, has a center lead 11 and two end leads 12 and 13 for rectification purposes. The two end leads are connected to any suitable rectifying device 14 and finally go out to lead 15. lead of the rectified current circuit. If desired, as comprising a plurality of-shunt condensersand series inductances, may be connected to smooth out the current impulses.

The resistance R is made variable so that the amount of current flowing through coil 3 may be regulated and thereby insure the proper operation of the device.

, The line current goes from lead 6 to tap 8 showing of the invector diagrams referring through coil 2 which forms primary 2 of the autotransformer and then to the primary 4 of the transformer and then to the other side '1 of the line. The secondary of the autotransformer comprises coils 2 and 3. The condenser C combined with the coil 3 of the 'autotransformer makes the autotransformer load capacitative with respect to the coil 3 and hence aids in regulating the system.

If desired, other secondaries 18 and 19 may be added on core 32 to provide filament supply for tubes or other purposes. 4

Referring to Figure 2, we have substantially the same elements and connections except that condenser C and resistance R. are connected across the entire secondary 2 and 3 of the autotransformer.

Referring to Figure 3 two'tr'ansformers Tand '1' are shown. T has capacitance C across its secondary which operates in such a way that the entire transformer load becomes capacitative rather than inductive; R1 and R2 represent the loads. V0 and Vi. each represent the capacitatlve and inductive load voltages in series ac the line.

In the vector diagrams, Figures 4 and 5, Figure 4 represents the inductive portion of the system,

namely T1 and its circuits while Figure 5 represents the capacitative portion of the entire loadthat is, transformer T and its circuits. 1; represents the line current. Along vector'Vr. may be laid of! vectors Ia and Ian. In represents the load current while 111+: represents the current losses due to hysteresis and eddy currents.

At right angles to the current vector, is ve t The central lead 11 is the other 3. The position of tap menses I which represents the magnetizing component of the current at right angles to the primary voltage. The resultant IQ of the two vectors law and 1., represents the no load operating current. The vector Ip, which is the resultant of In and I0, represents the current going through the primary of T1. In case T1 were a choke this current would, of course, be the current going through the choke. As can be seen, the angle between V1. and 11 represents the lagging current in T1.

Referring to Figure 5, V0, 1'1: and l' n are laid oil? in similar manner. The resultant lo is obtained in the same manner as in Figure 4. At right angles to V and opposite in direction to I", is laid off lc which is the capacitative leading current. Subtracting I'., from and then combining I'i-H-E with this difierence vector, we obtain vector Is. Combining this vector with the load current I'n, we finally obtain the resultant Ip which, as. above, represents the current through the primary of the loadin this caseof transformer T. It should be noted that since T and T1 have their primaries in series, IP will be the same in both instances and, therefore, vectors Is in Figures 4 and 5 are equal to each other. Figure 6 is a composite of both resultants of Figures 4 and 5. Taking vectorVp and laying Ip along in the same direction, we may obtain components V1. and V0 from the original VP. It should be noted that the supply line is assumed to have substantially unity p veer factor since Ip and Vp are in the same dir ction; Vc has been transposed about VP so as to close the triangle. I

Assume that VP varies. It is readily seen that this variation may be taken up in any one of three ways. The sides of the triangle V1. and V0 may both remain substantially constant while their angles with respect to each other and to the base VP may change. This, of course, is only true within certain limits. In addition, the lengths of the two sides V1. and V0, as well as their angles, may change to meet the changing length of VP. A third way is for the angles to remain the same as VP changes, while the lengths of VL and V0 change. It is also possible to have only one side of V1. or Vc change as well as the angles when base VP changes. The dotted lines V1. and V'o show a variation of base V1. V1. remains substantially constant while 0 varies as well as Vc.

Thus it can be seen that though base VP varies considerably, still V1. and V0 do not vary much, VL swinging and describing an arc of a circle. In my system, Ikeep at least one of the sides, preferably vn'cons'tant and allow Vc and the corresponding angles to vary as VP changes. I can, of course, keep both VL and V0 constant and merely allow the angles to vary, but this method is not as desirable from a commercial point of view as only'keeping one side constant.

Thus it will be seen that I have devised a system which will regulate to within close limits for variations of or departures from standard voltages. Furthermore, the system may be embodied in an apparatus which is cheap, and requires a minimum of parts and material and operates with a minimum of losses.

I claim:

1. A regulating system comprising a transformer having a primary and secondary, an impedance in series with the primary, said impedance having inductance, and a condenser associated with the impedance, the system therebyrib providing means for operating the inductance of one of the elements with which the condenser is associated so that a, small change of voltage results in a great change in the value of the inductance, all the magnetic elements having a common core.

2. A regulating system comprising a plurality of inductances in series, and a condenser in parallel with one of said inductances, the system thereby providing means for operating at least one of said inductances so that its value changes greatly comparedv to voltage changes, said inductances having a common core.

3. A regulating system comprising a plurality of inductances in series, at least one of said inductances being a transformer, and a condenser in parallel with at least one of said inductances, the system thereby providing means for operating at least one of said inductances so that its value changes greatly compared to voltage changes, one of said inductances being an autotransformer.

4. A constant current supply system comprising a. transformer having a primary and secondary, an inductance in series with the primary, said transformer and inductance having a common core, and a condenser associated with at least one of the series connected elements, the system thereby providing means for operating the element with which said condenser is associated so that small voltage variations result in large inductance variations.

5. An alternating current regulating system adapted to supply a. substantially constant alternating voltage from a line in which voltage fluctuations occur comprising means for breaking up the line voltage into a plurality of portions, means for causing a. phase displacement of said voltages andfor causing a variation of said phase displacement as the line voltage varies, and means causing any further line voltage variations to be restricted to one of the voltage portions, all of said means comprising a plurality of inductances on a common core.

=3. A regulating system, comprising a plurality of inductances in series and a condenser associated with one of said inductances, at least one of said inductances being so operated that its value changes greatly compared to voltage changes, all of said inductances having a common magnetic core.

'7. A regulating system, comprising a network consisting of a plurality of inductive and reactive lmpedances in series, all of said inductive impedances having a common magnetic core, a source of alternating potential connected to two spaced points in said network, at least one of said reactive impedances being so operated that its value changes greatly compared to voltage changes impressed thereon.

8. An alternating current regulating system adapted to supply a substantially constant alternating voltage from a line in which voltage fluctuations occur, comprising means for breaking up the line voltage into a plurality of components, means for causing a phase displacement between said components, and means for causing a variation of said phase displacement as the line voltage varies, said means being so designed that said variations in line voltage produce variations in magnitude of but one of said components, each of 'said means including an inductance and all of said inductances being provided with a common magnetic core.

WILFRED K. FLEMING.

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