Патент USA US2412046код для вставки
Dec. 3, 1946. 2,412,046 . s. c. HoARE RESONAN'I‘ cmcun' SATURABLE CORE MEASUREMENT APPARATUS ‘ Filed Sept. 8, 1943 FREQUENCY $0 CYCLES i 3A. 23'': 26 Inventor: Stepheh C.Hoar~e, by k’ ‘ 6.’ .dwlw Hus Attorney. . Patented Dec. 3, > ‘ 2,412,046 a UNITED STATES PATENT oer-1c}: BESONANT CIRCUIT SATURABLEbORE - I . I . MEASUREMENT APPARATUS Stephen C. Hoare, Manchester, Mam, asei'g'nor to General Electric Company. a corporation of New York Application September a, 1943. sci-lame. 501,549 4Clalms. (01. 175-183) ~ 1 I 2 . . _ Q It is known that anarrangement similar to that here shown in Fig. 1, omitting the condenser I‘. My invention relates to unidirectional ?ux satu rable core measuring apparatus and circuits, and its object is to provide such apparatus of high sen sitivity and amplifying ability. An important as can be used to measure direct current by measur- . pect 01' my invention is the use of a tuned circuit or circuits in which there is included, as a variable inductance, a saturable core. Where two tuned circuits are employed, a diil'erential amplifying of the core ll. ing the alternating current by a meter ll, due to v the variation in the inductance of the alternating current circuit by-various degrees of saturation However, when the alternating ' current circuit is tuned by means of a condenser‘ and the circuit is properly used .over the slope of e?ect may be obtained by operation of the two cir cuits on di?‘erent slopes or in‘reverse direction on 10 the resonance curve, a large increase in sensitivity is obtained. Let it be assumed that with no di the same slope of their resonant curves over the rect current ?owing in coil l2, the alternating cur detecting or measuring range. These and other rent circuit has a resonant curve a, Fig. 2, and features of my invention will be explained in con operates at the point a: of such curve for the fre nection ‘with the accompanying drawing, while the features which are considered to be novel and 15 quency 01' source iii which is assumed to be con stant at 60 cycles. Hence, at such time a current patentable will be pointed out in the claims -ap-‘ :6 will ?ow in instrument l‘l, but its indication may pended hereto. ' be suppressed as, for example, by adjustment of ' Fig. 1 represents a simple embodiment of my in the zero return spring so as to have-a scale-read vention involving a resonant circuit inwhich a change in tuning isvobtained by a saturable core 20 ing of zero. Now with direct current ?owing in coil l2, corresponding to the upper limitof the reactor. Fig. 2 shows resonant curves explanatory direct current to be measured, the circuit con-. of Fig. 1. Fig. 3 shows an arrangement where a stants can be so arranged that resonant curve pair of saturable core resonant circuits are em characteristic of the alternating current circuit curves explanatory oi the arrangement of Fig. 3. 25 will be represented by curve b, because due to sat uration of core i I the inductance in the alternat Fig. 6 represents a compass application of my in ing current circuit has been decreased, and hence, vention where the degree of saturation is con— the alternating current circuit will be, tuned to trolled by the earth’s ?eld. Figs. 7 and 8 are res ployed differentially. Figs. 4 and, 5 are resonant . resonance at a‘ higher frequency than before. onance curves explanatory of Fig_‘6, and Fig. 9 represents a further embodiment of my invention 30 , However, the frequency remains constant, so that a current 11 now. flows in the instrument ll. ‘ I where the di?'erential resonant circuit principle is combined with a push-pull alternating current excitation ampli?er scheme. have found that the sensitivity of the arrange ment can thus be greatly increased by simply add ingth'e condenser and taking advantage of the ’ I In Fig. 1 let i0 represent a'direct' current circuit in which it is desired to measure the current. H represents a saturable-core of high permeability magnetic material having a, low saturation point, such for example, as mu metal. This core is mag netized by unidirectional ?ux in proportion to the direct current to be measured by a winding 12 con nected across a shunt IS in the circuit I0. I 4 rep resents another winding on core Ii energized by as resonant principle. , In Fig. 3, I have provided two saturable cores ' l8 and I9'each provided with saturating direct current windings .20 and 2| energized in series from a source ill, and alternating current wind ings 22 and 23 energized in parallel from a, con stant frequency source i5. Condensers 24 and 25 are provided in the parallel circuits of coils 22. and 23. A full wave direct current recti?er in strument 2615 connected to respond to the differ ing i4 is in series with a condenser l6 and an al-v ternating current responsive instrument II. It 45 ence, if any, in voltage across the coils 22 and 23. It is noted that the direct current coils on the two is seen that the alternating current circuit con cores are wound in the opposite direction, while tains an inductance H which is varied by the de the alternating currentwindings are wound in the gree of saturation of the core II, and the con same direction. The same e?ect would beobl. denser “5 which may also be variable for calibra tion purposes. However, the saturable core in so tained if the direct current coils, were wound the same and the alternating ‘windings were wound ductance is the measurement variable of the A. C. in opposite directions. , _ l, ‘i _ circuit. The circuit will also contain some re I'n,the arrangement _of_ Fig, Liv when therefisnq sistance, and the sharpness of the resonance curve alternating current from a source l5.. The wind of the circuit will depend upon the amount of re sistance therein. a - ' ’ direct. wrrent , ?owing, the altcrnatinai current; circuits‘are vso‘ adjusted that‘ theclr'cuit contaim‘ 2,413,040 ing winding 22 and condenser 24 operates at about the midpoint of the high irequency slope of its resonance curve as at point 1:, curve 0, Fig. 4, while the circuit containing winding 23 and condenser 25 operates at about the midpoint of the low frequency slope oi its resonance curve as mum amount oi the earth's ?eld in a given di rection. ’ ' The adjustment oi the apparatus is as iollows: When the earth's ?ux pickup strips l8 and I! are turned in an east-west direction so as to pick up none of the earth's magnetic ?eld, the current in coils 28 and 23 is adjusted so that the strips at point 1:, curve 11, Fig. 5, and iurther, so that I8 and I9 are partially saturated and the con equal currents a: ?ow in the parallel alternating densers 24 and 25 are adjusted so that the circuit current circuits. Under these conditions it will be apparent that the voltage across which the l0 oi.’ condenser 24 operates at point 11:, curve ‘la, Fig. 7, and the circuit oi condenser 25 operates recti?er instrument “is connected will be zero. at point 3:: on curve 8a, Fig. 8.- At this. time, and no current will ?ow in the recti?er instru then, the currents in coils 32 and 33 are equal ment. Now when direct current flows in wind > and the instrument 2’! has a central de?ection ings 23 and 2| to more or less saturate the cores and indication opposite the designation E-—W, i3 and IS, the reactances oi.’ the alternating cur 15 indicating that the ship is headed either west or rent circuits will decrease and at the upper limit east. Inasmuch as this condition will prevail of direct current ?ow the resonance curve 01' the when the strips I 8 and I3 are at right angles to alternating current circuit containing winding 22 the earth's ?e1d,~the instrument 2‘! will not, by will be represented by curve e, Fig, 4, and carry itself, indicate whether the ship is headed east an increased current 1:, while the resonance curve 20 or west, so that I provide a small, cheap compass oi the circuit containing winding 23 will be rep 34 which will point toward the designations E or - resented as at f. Fig. 5, and carry a decreased W depending upon the heading. The accuracy of current 2. Note that despite saturation of core I9, compass 34 needs to be su?lcient only to distin the current in its alternating current winding 25 guish between east and west. Now let us assume circuit decreases because of a further departure the ship is headed to true magnetic north, so from a resonance condition. The voltages across that the pickup strips I 8 and I! will pick up ‘windings 22 and 23 will be proportional to the maximum earth's ?ux in a driven direction. The difference in the currents y—-z ?owing there direction of current in coil 23 oi strip l9 is'such through, and this voltage is impressed across the 30 as to add its flux to the earth's ?ux in strip [9 recti?er instrument 2!! and produces a corre at this time and to increase the saturation of sponding ilow of direct current therethrough. It such strip, decreasing the inductance of the cor is seen then that the indication of the rectifier responding alternating current circuit and caus instrument ‘will be proportional to the direct ing it to have a resonance curve 8b and a current current ?owing in circuit H), but the amplifying 3;], Fig. 8. The current in coil 28, however, is in ability or sensitivity of the measuring arrange such direction as to oppose the earth's ?ux picked ' ment will be increased many times over non up by strip i8, 50 that the saturation of this strip is decreased and its corresponding alternating resonant saturable core measuring schemes of the prior art. . . current circuit now operates at‘ point 11/, curve In Fig. 6, I have shown a modi?cation of my ‘lb, Fig. 7. The ratio instrument 2‘! thus measures invention as adapted for a remote indicating mag the ratio of currents netic direction indicator where the variable £11 saturation e?'ect is controlled by the earth's ?eld. 72/ In Fig. 6 the core parts l8 and I9 are to be located so as to pick up the earth's ?eld. For 45 and the instrument indication is marked with the instance, they may be located on the wing of an designation N, which is the indication repre airplane sufficiently remote from vother magnetic sented in Fig. 6. material and disturbing in?uences to respond ac Now when the shiptis headed south, coil 28 curately to the direction and strength of the will add its ?ux to the earth's ?ux of strip l8. earth's ?eld, and with their alternating current 50 while coil .29 will oppose the earth’s ?ux oi strip windings connected with a remote indicator 2‘! Hi. The corresponding alternating current, cir arranged to indicate the direction in which the cuits will operate on resonant curves 1c and 8c _ airplane is headed. The core parts [8 and [9 are with currents ‘Ia and 82:, respectively, Figs. 7 of such dimensions and material as to become and 8. Under this condition coil 32 will pre partially saturated by the earth’s ?eld when dominate and the instrument will indicate 8. turned in line therewith, with the turning of the For intermediate headings the instrument will airplane or other structure to which they are have intermediate indications, and the scale may ?xed. The earth’s ?eld takes the place of the be calibrated in direction angles accordingly. If direct current windings 20 and 2| of Fig. 3, and the apparatus is used in widely di?erent localities there are in addition, biasing direct current wind 60 such that the strength of the earth's ?eld varies . lugs 23 and 29 wound oppositely on the two cores appreciably, recalibration for the diiierent con and connected in series to a direct current source ditions will be called for. 30 through an adjustable rheostat 3| . The alter The push-pull feature of Fig. 6 represents an nating current windings 22 and 23 and the con improvement even without utilizing the resonant densers 24 and 25 in series therewith correspond 65 features. However, including the resonant prin to like elements in Fig. 3. The instrument 2'! is - ciples described very materially increases the shown as a ratio instrument having coils 32 and sensitivity. It is to be understood that the nature 33 connected to measure the ratio of currents in of the instrument or other device of 21, Fig. 6, the parallel alternating current tuned circuits. may be any instrumentality which will respond This instrument can be either alternating current 70 to the current ?ow in the parallel alternating or recti?er direct current so long as it responds ‘ current circuits to give a signal ‘or response in to the ratio oi the al-temating currents. - accordance with the ratio of the currents in such In the illustration it is assumed that the upper ends of the core parts l3 and H are toward the parallel circuits. magnetic north, and therefore, picking up a maxi _ ' The sensitivity or ampli?cation response of 75 the resonant push-pull saturable core arrange 2,412,046 ' ment of Fig. 3 or 6 may be further increased by ( a di?ferential inductive coupling between-the par-. current and alternating current windings on one core being similarly wound and those on the other allel alternating current circuits and the saturable ‘ core being reverseiy wound, a common source cores employed as represented in Fig. 9. Except of alternating current supply for said parallel cir for the additional alternating current windings 5 cults, said circuits being so tuned that corre .- 36 and 31 in Fig. 9, the arrangement is equiv sponding changes in the unidirectional ?ux inthe alent to that shown in Fig. 3, and equivalent pair of core parts cause the current in one circuit parts are designated by like reference characters to increase and the current in the other circuit in the two ?gures. It is seen trim in Fig. 9 the to decrease, and means associated with both of circuit of alternating current winding 23-on 10 saidrtuned circuits responsive to the differential core is has a low turn winding 36 on core I8 current?ow in said parallel circuits. wound in opposition to the main alternating 2. ‘Unidirectional ?ux’ responsive apparatus current winding 22 thereon, and likewise, the I comprising apair of magnetic core‘parts so dis y» circuit of alternating current winding 22 on posed as to intercept unidirectional ?ux under core I8 hasa low turn winding 31 on core l9 15 investigation and to be subject to varying degrees wound in opposition to main alternating current ' of magnetic saturation by variations in‘ the mag nitude of the ?ux‘intercepted, awinding on each the effective alternating current excitingampere " of. said‘ core parts, means for connecting said turns to change faster than the change in alter windings in parallel circuits to an‘ alternating ' nating current exciting current. Let it be as 2 current supply. means including said windings sumed that coils 22 and 23 each have 100 turns for tuning said circuits such that corresponding and coils '36 and 31 have 20 turns and that when changes in the magnitude of unidirectional ?ux intercepted by said core parts will cause the cur the currents in the two alternating current cir winding 23 thereon. ‘This arrangement causes \ cuits are equal; one ampere ?ows in each circuit. rents in the parallel circuits to'vary inversely, _ and means vresponsive to the differential current Then the effective alternating current ampere turns in each alternating current circuit are 1oo-2o=ao.. Now assume that because of a ?ow in said circuits. _ 3. Unidirectional ?ux responsive apparatus subject to magnetic ?elds comprising a pair of di?'erent condition of saturation, the alternating elongated magnetic core parts mounted parallel current exciting current of winding 22 increases by 10 per cent and that of winding 23 decreases to each other, direct current winding means on by 10 per cent. Then the e?ective ampere turns ~, said core parts for producing reverse unidirec ~tional ?ux biases in said core parts such that in branch 2: become 110—18=92, and the ei‘i'ece tive ampere turns in branch :3 become 90—-22_—.88. ' ' when in line with a unidirectional magnetic ?eld Thus the 10 per cent change in- exciting current such ?eld, with the biasing ?ux, will substan causes a 15 per cent change in effective ampere ” tlallyv saturate one core part and substantially‘ turns in the differentially coupled alternating demagnetize the other core part, alternating cur current circuits. The reactance in each alter rent windings onsaid core parts, means for .con nating current circuit branch .is proportional to the eil'ective alternating current ampere turns. necting said windings in parallel circuits to an‘ _ alternating current source ‘of supply, means in Hence, a change in saturation in?uencing the re .10‘ cludlng ‘said windings -ior tuning said parallel actance or effective ampere turns-is ampli?ed - circuits such that said circuits operate on sim by such din‘erential or cross-coupling or the al ilar slopes of their resonant curves and have“ ternating current circuits. This is- in addition substantially equal currentswhen the core parts to the ampli?cation obtained by the dl?erential are in neutral positions relative to’ the ?eld, and resonance principle employed. By the proper 45 mea'nskresponsive t9 the current flow in said use of the diil'erential resonance principle and parallel circuits to give a signal in accordance the diil'erential coupling oi’ the alternating cur- rent circuits, an ampli?cation oi the order of - six times the with the ratio of the currents in said parallel circuits. - . ' ' sponse'oi' the ordinary saturable ' 4. Unidirectional ?ux responsive apparatus core arrangement may be realized. ' 50 comprising a pair of magnetic core parts adapted ' - In accordance with the provisions of the patent to intercept unidirectional ?ux under investiga statutes, I have described the principle of opera tion and to be subject 'to various degrees of satu ' tion oi'.my invention together with the‘apparatus ration-by variations in the‘ ?ux intercepted, a .. ~whichI now’ consider to represent the best em main exciting winding and an auxiliary bucking bodiment thereof, but‘! desire to have it under “winding on each core part,'a tuned circuit in stood that the apparatus shown is only illustra eluding the main winding-on one core part and tive and that the invention may be carried out by other means. _ the auxiliary bucking winding‘ on the other core part, a‘second tuned, circuit including the re maining windings on the core parts, connections ,. What I claim as new and desire to secure by . Letters ‘Patent of the United States is: 90 for energizing both of said circuits in parallel - L-Unidirectional ilux responsive apparatus from a common source of alternating current comprising a pair of magnetic core parts adapted . supply. the tuning of said circuits being such .to be threaded by the flux under investigation and to be subject to varying degrees of saturation - as to cause their currents to vary inversely with respect to each'other by similar changes in the by changes in the unidirectional ?ux threading as ?uxes intercepted by the core parts, and means ‘ said- core parts, a pair oi’ windings energised currentv on said cores. 0. pair of parallel timed circuits'including alternating current ex citinrwindings on said core parts, the direct . ' associated .with both of said tuned circuits re-‘ sponsive, to'the relative magnitude of current ?ow in said parallel circuits. " . ' ' ‘ ' . C. BOAR‘.