US1099960A - Electric converter. - Google Patents

Description

G. I. ZIMMERMAN, DEGD. J. a. ZIMMERMAN, ADMINISTRATOR. ELECTRIC CONVERTER.

APPLICATION FILED 0012.17, 1906.

Patented June 16,1914.

4 SHEETS-SHEET 1.

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C. I. ZIMMERMAN, DEUD. I. G. ZIMMERMAN, ADMINISTRATOR. ELECTRIC CONVERTER.

APPLIGATION FILED 0O'I'.l7, 1906. I 1,099,960, Patented June 16,1914.

4 SHEETS-SHEET 2.

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e170 2 Mme/"man, w; by w Wt 231 G. I. ZIMMERMAN, DBCD. J. G. ZIMMERMAN, ADMINISTRATOR. ELECTRIC CONVERTER.

APPLICATION FILED 0OT.17, 1906. 1,099,960, Patented June 16, 1914.

4 SHEETSSHEET 3.

Witnesses.-

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C/ r'enceZZ'mm/"Man b [v t G. I. ZIMMERMAN, DEGD. J. G. ZIMMERMAN, ADMINISTRATOR.

ELECTRIC CONVERTER. APPLICATION FILED 00T.17, 1906.

Patented June 16, 1914.

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7 INVENTUH CLARENCE .Z. mMERA IAAL ATTY 'fication.

' TATES PATENT orrron.

cLA'nENcE IRVING zmMERMAN, or NIAGARA iliALLS, NEW YORK; JAMES e. ZIMMER- MAN, ADMINISTRATOR OF SAID CLARENCE I. ZIMMERMAN, IQECEASED, ASSIGNOB.

'ro enrtEBA -Emcr'mc COMPANY, A coRPon 'nouor NEW YORK.

- ELECTRIC CONVERTER.

' specification of Letters Patent. Patented June, 16, 1914;,

Application filed October 17, 1906. Serial No. 339,399.

To all whom it may concern Be it known that I, CLARENCE LZIMMER- .wr.-\X,'"a"citizen of the United States, residing at Niagara,Falls,--co1inty of Niagara, State of New York, have invented certain new and useful Improvements in Electric C011.- verters, of which the following is a speci- This invention relates to the conversion of alternating current nto uni directional current or other- --fo1"ms having special qualities applicable to various electrotechnical uses.

I have hereinafter described several distmct types of apparatus suitable for carrying out my improved method, and although the separate types varlous specific characteristics, neverthe less, they all embody the basic idea of my invention,

My system includes one or mOre asymmetric conductors together with means for plates immersed taining one accumulating a very appreciable electrostatic charge. In thosespecies wherein I have used a mercury vapor tube as an asymmetric conductor, I have combined with itan electrostatic condenser of the ordinary type. In those species in which an electrolytic asymmetric conductor is used, I make use of the peculiar, electrostatic capacity of the asymmetric conductor itself, thus, ina sense, combining the condenser in a single unit. I am aware that mention has heretofore been made of the electrostatic capacity ofan electrolytic cell consisting of two aluminum in a suitable electrolyte. I am also aware that electrolytic cells conaluminum electrode and one carbon or iron electrode have been used for. the rectification of'current. I am not aware, however, that it has ever been proposed to utilize simultaneously the rectifying and electrostatic *properties of such cells, particularly when disposed in such systems as are hereinafter described.

According to my improved method of rec-'- tificatlon, the alternating; current maybe converted into uni-directional current,

' cithersteady or pulsating, and this unidi' rectional current may have avoltage higher age.

are distinguishable by- "than that of the original alternating current. In fact, :according to some of the species hereinafter described, tional voltage may be several times higher than the original alternating current volt- So far aS'I amaware, this resultis broadly new 4 As-Will appear tailed description,

instead of simple rectification, a condenser is so connected that it acts to boost the volt+ age at the load circuit, the entire system be: ing such that by changing the connections for the load circuit, the condenser may be used to equalize the load potential instead of boosting it,

a part of this specification, grammatic representation of asimple form of. rectifier using a mercury vapor asymmetric conductor and an electrostatic condenser of the usual type. Fig. 2' ives a similar system utilizingltwo vapor tu es and a condenser. Fig. 3 illustrates a. system similar to that of Fig. 1, except that the rectified current is of positive polarity at the central or intermediate terminal. Fig. 4 corresponds to Fig. 2 except that by a reversal of the asymmetric conductors, the polarity of the rectified current is reversed. Fig 5 is a diagrammatic representation of a system in which he electrostatic condenser and asym:

of the systems shown in Figs. 1 and 3, .the"

What I choose to term a former illustrating negative rectifier and the latter a positive rectifier. A 8 shows a system in which three vapor amps orvalves are utilized in connection with two large electrostatic condensers'toyield direct current of from the followingdc the system of. my presentv ,IIIVQntlOIl is a rectifying system in which,

In the drawingsannexed to and forming- Figure 1 is a di'a.-

the uni-direcsubstantially constant voltage.v Fig. 9 shows a systemin which three electrolytic cells'are V Fig. 10, showsan arrangement for increasing still further the diflerence. between the potential of the direct current output and the alternating current input. This differs "from the arrangement of Fig. 9 by the inany appreciable current in the .electrical potentials between. various having an aluminum electrode, i

clusion of a second electrolytic condenser connected between the direct current terminals. Fig. l1--shows a new type of asym-.

metric conductor, and illustrates its use in a system of rectification. Fig. 12 illustrat% a polyphase-system for producing and utilizing a rotating electrostatic charge. 13, 14:, '15, 16 and 17 are curves illustrating parts of the systems shown in the other figures.

In several figures of the drawing. Ihave illustrated a mercury vapor tube orlamp as an asymmetric conductor or valve to transmit current in one direction and to prevent the flow of currentin the opposite direction. Such a tube or lamp may consist, as illustrated in Fig; provided with an anode 2 of solid material, and a vaporizable cathode 3 of mercury. A second or auxiliary anode 4 is also'provided and is supplied with current from a battery 5 or other source of energy, for the purpose of maintaining a continuous are from the mercury cathode 3. This auxiliary arc, or

side branch, serves to maintainthe' tube in such a condition that it will transmit current tending to flow from the solid anode 2 to the mercury cathode 3, but will. prevent current flow in the opposite direction. The

valve-like action of a mercury vapor tube is.

also present in an electrolytic cell of the type combination with an electrode of inert ma erial, such as carbon, platinum or iron, and an electrolyte capable .of developing an insulating coating on or about the aluminum elect-rode. Such a cell will transmit current readily from the inert or carbon electrode to the aluminum electrode, but will. not transmit opposite direction. Probably this asymmetric action is due to the formation of -a coating of oxid, hydroxid or other material on the aluminum plate, this'coating being of extreme .thinness and high resistance. These properties of an aluminum electrolytic cell are well known. r

In addition to the asymmetric property of an aluminum cell, I find that by proper disposition of the electrodes, at veryappreciable' electrostatic capacity may be obtained,

. and furthermore, that the condenser action of the cell may be utilized in connection Figs.

1, of, an mclosing envelop 1 I with the other elements here shown, for

the rectification of alternating current, and for its conversion into unidirectional current of pulsating character or into current of substantially constant potential. According to my invention advantage is taken of the properties of an electrolytic cell, of combining in itself both the properties of an asymmetric conductor and the properties of a condenser, and this dual role which the electrolytic cell is able to play, I may take advantage of by substituting an electrolytic cell in place of a vapor 'tube and a tinfoil condenser in] the system herein disclosed and claimed.

In the following detailed description of my invention, I have illustrated species utilizing vapor :electric'valves, and other species using electrolytic valves, and in those systems using vapor electric valves I have an ranged tin foil or similar condensers in those parts of the circuits,requiring electrostatic capacity, while in the systems utilizing electrolytic valves I have relied on the electrolytic. cell itself to supply the neces- 'sary capacity. It should be understood that the illustrations of electrolytic cells shown in the drawings are merely diagrammatic, and that in practice I could increase the eler trostatic capacity by increasing the area of the aluminum electrode in any suitable way.

Fig. 1 illustrates a system of rectification, and comprises, in addition to the vapor elec tric device heretofore described, an electrostatic condenser 6 of the tin foil or other well known type, and an alternating current source, such as a transformer having a primary-7 and a secondary 8. The cathode 3 of the vapor tube is connected to one of the leads 9 of the transformer secondary and a condenser 6 is connected between the anode 2 of the vapor tube and the other lead 10 of the alternating current source.

rThe' condenser 6 is preferably large enough in capacity to permit an appreciable flow of current from the transformer main 10 through the vapor tubeto the other terminal of the transformer. As current cannot flow back through the vapor tube to equalize the charge in condenser 6 when the potential of the source reverses, there re sults a negative charge on the conductor connecting the condenser to the vapor tube, this charge establishing a potential across the conductor terminals equal to the maximum potential across the transformer secondary 8 less the drop in the rectifying arc tube. readily apparent upon consideration of the flow of current out of the condenser when the transformer lead-1O becomes positive, and the absence of return current when that lead becomes negative. As lead 10 becomes positive, it communicates a positive char e to one side of condenser 6, and thereby in uces That this value is correct will be may be relatively small say to volts,

and the voltage of the source may be as high as several thousand volts the condenser receives substantially the maximum the transformer secondary and that pothe conpotential of 1 takes up a charge corresponding to tential. When the source reverses,

- denser is prevented from discharge by the by connecting the substantially double ,mum

.to terminal 13'.

valve-like action of the vapor tube, and

tends to maintain across its terminals a constant potential equal to that of the maximum value developed by the alternating current source. After the first cycle of the alternating current source, the condenser connected as above described neither charges nor discharges but maintains a definite steady voltage across its terminals. If, now, means are*provided for taking ofi a small partof this charge, .the energy so taken off will-be substantially constant -potential and at a voltage equal to the maxipressure of the alternating current supply less the drop in the rectifier tube. For conveniently utilizing this charge, I have provided the transformer terminals 9 and 10 with terminals 11 and 12, and; I have connected a'third terminal 13 to the conductor connecting the condenser 6 to anode 2 of the vapor tube. Translating devices such as lamps, motors, etc., connected between terminals 12 and 13 will receive uni-directional current of substantially constant. voltage, the current passing through the translating devices from terminal' 12 It should, of course, be understood that thecapacity of condenser 6 must be made large enough to supply the desired energy to the translating devices without great loss charge, as otherwise, will receive pulsating current the translating devices instead of constant potential current.

'My system of rectification provides not only for the production of constant potential direct current as above described, but also for the production of directional current. This may be obtained translating device between the terminals 11 and 13, the terminal 11 being positive and the terminal. 13 being negative. Between these terminals the potential periodically varies from zero to practically twice the-voltage of the transformer secondary, for when terminal 11 is at -its maximum negative value, terminal 13 is at substantially 'the same potential, but when the polarityof the-source reverses, the condenser and source act'in series toqdevelop potential across the terminals 11 and 13-, and thus make this doublepotential available to perform useto cut the wires between ing operation in the potential of the pulsating uniful work. In practice, it sometimes happens that this maximum potential falls a little below the calculated value because of irregularity in the wave shape of the transformer current and because of leakage in tube, persons skilled in the art, and which need not be referred to except as sources of the slight discrepancies which may arise be- -7o i the condenser and voltage drop in the vapor factors which are well understood by v tween the theoretical values of the voltages and the values obtained in practice. These difierences are mainly of theoretical interest and will not be further discussed herein.

A somewhat homely explanation of the double potential available momentarily between terminal 11 and 13 may be made as follows: Assuming that the condenser (i is receiving its'charge, the potential at its terminals will rise to substantially that of the transformer secondary 8 (neglecting the ipoltage drop in the :tube) then if we were the condenser and transformer before the potential had time tore-verse, we would have stored in the condenser -a charge, the voltage of which is constant and equal to the maximum'instantaneous voltage of the transformer secondary. Then let us assume that the transformer voltage reverses in polarity and after that reversal is complete, we connect the condenser with the secondary, in such a way that it serves to boost the voltage of the secondary. This will give a voltage between the free terminal of the secondary, substantially double that originally impressed on the condenser, the effective current supplysource acting in series with the transformer second 8 between points 11- and 13. But instead of by hand rectifier of the present system doesit for us.

,At each half wave it connectsthe condenser for a charge and -at the subsequent half wave it disconnects the condenser at one end leaving it connected in at the other end in such a way that it boosts the reversed voltage of the transformer secondary.

For a better understanding of the poten-. tial difierences between various parts of the system described, reference may be had to Fig. 13 in which these difierences are graphically illustrated. Let itbe assumed that the horizontal line 13 is a curve representing the potential at the terminal 13 in Fig. 1 and that vertical distances above being the condenser 6- performing this connecting and disconnectas above assumed, the

this line are positive potentials with respect For purposes of'discussion, the terminal 13 may be considered as at earth otential. When the condenser of Fig. 1 has been charged to its maximum voltage, the potential of terminal 12 will be positive with respect to terminal 13 by an amount equal to the maximum momentary difference to terminal 13.

12 and 13. Of these two terminals 12 is positivewith respectto-13i Similarly the.

. vertical distance between curves 11' and 13 at any particular point oftime represents the instantaneous potential on open circuit between terminalll and terminal 13. Thus at the instant of time marked A,B, ter- .minal 11 is'at its maximum positive value with respect to termil l qll2 and'is at twice this value with respect to terminal 13. B

following along the curve to the instant marked O-D, it will be seen that terminal 11 drops to the potential of terminal 13, so that in passing from A-B to CD it drops to zero from a maximum equal to twice the maximum instantaneous difference of potential between 11 and 12, or in-other -words twice the maximum instantaneous voltage of the alternating current source.

ltswill be understood that when the load current is small with respect to the capacity of the condenser the curves of Fig. '13 will be substantially accurate for illustrating voltage available at the respective terminals for sending current through the load. If the load current is so heavy as to, pull down on the condenser voltage at-each discharge thereof, the wave shapes illustrated in Fig. 13 will be flattened out and modified somewhat, as will be readily understood.

Fig. 2 illustrates a transformer 14'and vapor tubes 15 and 16 connected respectively to the transformer terminals in such a way as to permit current to flow from either terminal to a binding post 17 which thereby becomes a positive terminal of the consumption circuit. A condenser 18 of relatively high'electnostatic capacity is connected in shunt with vapor tube 16. The transformer secondary terminals are connected directly to bindingposts 20-and 21, from which connections may be made to the positive terminal 17 through the loads 22 and 23. When the polarity of the transformer secondary is such as to send current from anode to cathode in the vapor tube 15, a posltive charge is introduced on plates 24 and a similar inductive charge is induced on the opposing plates 25. A charge so Imprisoned cannot escape through the vapor devices 13 and 16 because of their asymmetric action, and can only pass off by way it being understoodthat the condenser is of ample capacity with respect to the resistances of the load circuit. If the load is connected at 22 instead of at 23 the charge of condenser 18 will pass from terminal 17 to terminal 20 and will be at substantially double the voltage of the transformer secondary, because of the fact that under these conditions, the condenser voltage is added to that of the transformer secondary or in other words the condenser boosts the transformer voltage. In addition tothe energy transmitted from terminal '17 to terminal 20 by way' of condenser 18, a certain amount is also.

transmitted directly from the source by way of vapor'tube'16, and this latter energy 1s,

of course, at the potential of the transformer secondary.

Fig. 14 illustrates graphically the instantaneous differences of potential between the terminals 17, 20 and 21 when no current is being used in .the load circuits-22 and 23. For convenience of reference, the terminal 21 has been considered at zero potential and therefore capable of representation by the horizontal line 21 shown in Fig. lir -V1111 this as a datum line the instantaneous values of the terminal 17 are properly represented by a parallel straight line 17 separated from the line 21 by. a distance corresponding to the maximum difference of potential of the alternating current source. Terminal 17 is always positive with respect t terminal 21 and consequently line 17' apears above line 21. The potential diference between the. terminal 21 and the terminal 20 is properly represented by a sine curve 20 symmetrically disposed. with respect to the line 21'.

From an inspection ofFig.. 14 itwill be seen that underthe condition of no load the ioo terminal 17 is at a constant potential above the terminal 21 equal to the maximum impressed voltage of the alternating source, and that it is at a potential above the terminal 20 by a potential which periodically varies from zero to substantially twice the impressed maximum voltage. This high voltage is of course produced bycharging the condenser 18 in parallel with the source and discharging it in series therewith. Although the curves shown in Fig. 14 properly illustrate the potential difference of the terminals under conditions of no load, they are not, unless the large condenser 18 be considered of infinite capacity, strictly accurate for a loaded system. If the condenser is notlarge or if the demands on it are heavy, the stored energy may be exhausted suiiiciently to give a illustrated diagrammatically in Fig. 15, as-

suming that either or both of the loads 22 and 23 are connected in.

From an inspection of Fig. it will be seen that the partial exhaustion of the condenser causes ,a slight droop in curve 17'. This means a decrease in the voltage on the load until curve 17 intersects the charging potential 20. Then the voltage on the load.

and the voltage across the condenser go up together and thecondenser starts off with a causes a rapid falling off the curve. 17 will not new'charge.

If the system shown in Fig. 2 be overloaded, the, exhaustion of the condenser in the potential of the terminal 17 at complete exhaustion the curve 17 intersects the curve 21. words, the terminals 17 and 21- reach the same potential. It happens, however, that cross the curve 21, for

further demands of the load 22 are supplied by energy passing directly through vapor device 16 to the terminal 17. This vapor device therefore performs an important function "in preventing from charging up with-the wrong polarity in case of an excessive demand in the load circuit 22. l

Fig. 3 shows a system in many respects similar to that of Fig. 1, and difieri'ngprincipally in the fact that the asymmetric conductor 26 is reversed, or in other words, is

connected to the transformer secondary by itsanode-lead instead of by its cathodelead. This makes the conductor 27 joining the condenser and vapor tube positive with respect to the transformer terminals 28,

The electrolyte being once charged negatively remains in that condition until equilibrium 29 but otherwise the voltage relations are substantially the same as that of the system shown in Fig. 1. For convenience in description, the system shown in Fig. I may be termed a negative rectifier, and the system of Fig. 3 may be termed a positive rectifier, and these terms are hereinafter used to describe elements of systems in which these positive and negative devices are combined to cooperate as for instance in Fig. 7.

Fig. 4 shows a system difi'eri-ng from that of Fig. 2 by a reversal of the asymmetric conductors to render the intermediate terminal negative instead of positive. To secure this result the vapor tubes 30 and 31' havetheir anodes connected directly to the intermediate conductor or terminal 32, and their cathodes connected respectively to the transformer mains 33 and 34 and the corresponding load terminals 35 and 36. The condenser 38 is connected in shunt with one of the tubes in the same way that condenser 18 of Fig. 2 is in shunt with its tube'16.

Fig. 5 illustrates my invention as embodied in an electrolytic asymmetricpconductor of the aluminum type. The system is noticeable drop in the In other the condenser 18 'tive,

.no opposition to he made up of a source-lot alternating current 39' connected directly to load terminals 40 and 41-. Across these terminals is connected an electrolytic cell 42 comprising a small aluminum plate 43 and a large aluminum electrode 44, an electrolyte 45 of the character commonly used in aluminum-asymmetric conductors, an inert electrode 46 of carbon, iron or platinum, connected to an intermediate load terminal 47. In practice, I make electrode 44 of large area and capable of holding a'high electrostatic charge, and I make the smaller electrode 43 of such small size that it possesses'little or no electrostatic capacity. I consider that the electrostatic capacity of an aluminum electrode is comparable to that of an ordinary tin foil condenser, and that the aluminum plate is one armature of the condenser, theelectrolyte the other armature, and the insulating. fihn or coating on the aluminum plate is the dielectric. For a complete understandingof my invention as embodiedin apparatus of the type illustrated in Fig. -5, it should'be noted that the electrolytic cell is a rectifier as well as a condenser:' When the polarity of the source is such that terminal 41 is posia positive charge is communicated to the aluminum plate 44, as one armatureof a condenser, and a corresponding negative charge is induced in the electrolyte 45, it being understood that this phenomenon 183C- companied by a flow of current from the electrolyte and the small aluminum electrode 43. The laiter opposes substantially flow of current from the electrolyte to the plate, although it does zoppose a practically prohibitive resistance to a flow of current in .the opposite direction.

;is restored through some other path. than ;that furnished by the aluminum electrode since current can never flow directly from the aluminum to the electrolyte. If, now, a

circuit is completed between terminals 41 and 47 or between 40 and 47 so that energy can enter the cell .by way of the inert electrode 46, then the condenser will tend to discharge and produce equilibrium between the electrolyte and the metal ofplate 44. If the condenser is of-sufficient capacity with respect to the return or load circuit between,

say' terminals 41 and 47, then the condenser will maintain a uni-directional current of substantially constant potential in this load circuit, and together with the rectifying action of the small aluminum electrode, will serve to convert the alternating current of the source into direct current for use between terminals 41 and 47. If the external circuit is completed by connecting the load between terminals 40 and 47, then the condenser acts in series with the source to boost the voltage to substantially twice that of the source, excluding, of course, the GIL, and leakage losses in the cell itself. The output is unidirectional and pulsating. The entire system of Fig. 5 is comp-arable to that of Fig. 1, and' since the intermediate terminal 47 is negative, I choose to term the device, as a whole, a negatlve rectifier.

.As contrasted with the negative rectifierof Fig. 5, I have shown in Fig. 6 a positive electrolytic rectifier for producing effect the desired results. With the arrangement as described, the intermediate terminal 55 is positive with respect to terminals 49 and 50, and the electro-motive force between 55 and 50 is substantially constant and equal to .the maximum value of the alternating current source, while the voltage between 55 and 49 is pulsating and reaches a maximum value approximately twice the maximum of the source.

In all of the modifications above described,

\ j the maximum steady voltage of the rectified current'has-been substantially equal to the maximum alternating current pressure, but

in the systems I am now about to describe, the pressure available is two and even three times the maximum value of the alternating current source. This effect is produced by combining whatI have termed positive rectifiers with negative rectifiers in such a way that their effects are cumulative. The principle involved is broadly applicable to any asymmetric circuit in combination with one or more electrostatic condensers.

By combining the negative rectifier of Fig. 1 with the positive rectifier of Fig. 3,

I'obtain the system shown in Fig. 7. One rectifier 56, has its cathode connected to the main of the source, and its anode connected through a condenser 57 to the opposite transformer-main. The other vapor tube 58 has its anode connected directly to the transformer secondary and its cathode connected through the condenser 59 to the opposite terminal of the source. The junction between vapor tube 56 and condenser 57 is always at negative potential, while the junction between rectifier 58 and'condenser 59 is always at positive potential, and the load 60 connected between these junctions is traversed by a unidirectional current of substantially constant potentiahthis potential being approxi matelv twice the maximum value of'the alternating current source. My invention will be readily understood if it is noted that the condensers 57 and 59 are charged in parallel and discharged in series.

Fig. 8 shows a system in which three vapor tubes are utilized as asymmetric conductors. Two of the tubes, 61 and 62, have their anodes'connected to a common terminal" 63, and their cathodes connected respectively to the alternating current mains 64 and 65. Tube 61 is shunted by condenser 66 of relatively large electrostatic capacity. These elements constitute a negative rectifier and serve to keep the terminal 63 at a constant negative potential with respect to the alternating current main 64. Combined with this negative rectifier is a positive rec-- tifier consisting of a vapor tube 68, having its main anodes 69, and 70, connected respectivelyto the line conductors 64 and 65, and its cathode connected to a load terminal 71. Condenser 73 is connected between load terminal 71 and the alternating current main 65. This positive rectifier serves to keep the load terminal 71 at a positive and con.- stant potential with respect to the alternat;- ing current main 65. If theload 74 is con} nected between the charged terminals 63 and 71 current will flow from the terminal 71 to 63, and the voltage-of the energy transmitted will be the resultant of the two condensers discharging in series combined with'the energy delivered directly from the alternating, current source by way of the'vapor tubes. In other words, the unidirectional current delivered is the resultant of an alternating current having substantially the potential-of the alternating current source, and a direct 'current having substantially double the maximum voltage of the alternating current source. The average value of the resultant is twice the maximum value of the alternatlng pressure wave. The efiective value is the vector sum of this average value and the value of the alternating pressure wave; the maximum value is three times the maximum value of the alternating pressure wave; the minimum value is equal to the maximumof the alternating pressure wave. In these calculations the voltage drop in the asymmetric conductors and the leakage and other; losses in the condensers, have of course, been excluded. It will be understood that the condensers 66 and 73 must be properly proport-ioned with respect to the load in order that the condenser voltage may not drop ofi abnormally when the load circuit is closed.

For a better understanding of the potential difference between the various parts of the system, reference may be had to Fig. 17. For convenience of reference, the terminal 63 is taken as the point of zero potential and all other parts of the system are referred thereto. The propriety of this assumption will be apparent when it is considered that terminal 63 might be grounded and thus placed at zero potential with re-' alternatmg supply source. This constant.

voltagedlfi'erence is of course maintained by the storing and restoring action of condenser 66. The supply lead 65 variesin potential with respect to conductor 64 in a simusoidal relation, as illustrated by the curve 65. Conductor 65 is separated frombinding post 71 by a condenser of large capacity and therefore binding post 71 is at constant potential from conductor 65, as illustrated by curve'71.

From an inspection of'Fig. 17 it will be seen that the maximum difference of potential between. binding post 63 and binding post '71 corresponds to the maximum dispress it differently,

tance between curve 71 and curve 63 and is equal to three times the maximum impressed voltage of the system. The minimum dif ference of potential between these binding posts equals one times the maximum of the system. The load potential is composed of three components; two uniform and equal potentials, and the alternating current source itself, all acting in series. To exthe pressure between the terminals 71 and 63 is composed of two equal uni-directional pressures with an alternatingpressure superimposed upon them.

As previously stated,-the potential differencebetween terminals 71 and 63 attains a maximum three times the maximum of the alternating current transformer voltage, and .then drops to 'a value equal to only one times the maximum potential value of the transformer. In order therefore to obtain a uniform or practically uniform difference of potential equal to three times the maximum value of the transformer voltage, it is only necessary to store energy during the peak of the'pulsating energy.

Fig. 9 shows an .electrolytic system in many respects analo ous to the vapor tube system of Fig. 8. W0 electrolytic asymmetric. con'ductors 75 and 76 have their inert or iron electrodes 77 and 78 connected respectively tothe alternating current mains 79 and 80.' Cell 75 isprovided with an aluminum electrode'81 of negligible electro static capacity, and this is. connected directly to the load terminal 82 and also to the aluminum electrode 83 of the other electrolytic cell. ,This last named electrode has a large surfacearea and is-intended to have a very appreciable electrostatic capacity. The apparatus just described constitutes a positive rectifier, and maintains,-ortends to maintain the load terminal 82 at positive 83, and by current main 80. The negative rectifier of the system consists of a single cell'8a provided with a large aluminum electrode 85 and a smaller aluminum electrode 86, this combination serving to keep the load terminal'87 at a constant and negative potential with respect to the alternating current main 79 When the alternating current main 79 is positive, current flows through cell-75. from anode 77 to aluminum electrode 81 and thus brings the load terminal 82 to positive potential and charges condenser 7.6. Simultaneously a positive charge is transmitted to the large aluminum plate potential with respect to the alternating of cell 84, and this renders the electrolyte and load terminal 87 negative by driving current through the small aluminumplate 86 to the other load terminal. This negative charge cannot escape when the potential of the main 79 drops back to zero, and consequently, acts in conjunction with the positive charge on the opposite terminal to force current throughany load connected between these terminals. The voltage of the currentdischarge is the resultant of the combined action of the condensers and the alternating current source.

' When the polarity reverses and the conductor 79 becomes negative, current can flow from conductor 80 through cell 76 to electrode 83 and then through the load which connects 82 and 87, and on through cell'84 to electrode 85. The voltage of the transformer, when thus applied to the load through the two electrolytic cells, is boosted by the condenser charge held at electrode the condenser charge at electrode 85, and it is this boosting of the transformer voltage which'gives to the .load circuit between 82 and 87 a maximum voltage substantially three times that of the maximum instantaneous voltage of the transformer. While conductor 80 is positive, current cannot leave electrode 86 because it is of aluminum, and, likewise, current cannot leave electrode 81, these electrodes being cut off by their insulating films as soon as the polarity of the transformer reverses.

Fig. 10 shows a combination of cells simi-,- lar to that of Fig. 9, but with the addition of a cell 88 placed between load terminals 89 and 90. This cell has two opposed alumiup energy and smooth out the pulsations of the unidirectional current delivered to the load terminals 89 and 90,-so that this pressure is uniform and higher in value than the average value of the pulsating current supplied the two terminals 89 and 90. This result is effected by the condenser properties of the cell which insure its discharge at a ties.

pressure equal -to the maximum voltage of the pressure momentarily impressed on its terminals by the unidirectional pulsating pressure supplied to electrodes 92 and 91. There is, then, a uniform static charge bound up in this cell 88 having a pressure which is theoretically equal to three times the maximum value of the alternating pres sure on the circuit. Any receiving device, such as a consumption circuit 93 placed across this cell 88, will be actuated by this triple voltage, and of course, will at the same time tend to lessen the uniformlty in proportion to the amount of energy drawn ofi. That there may be an available load potential equal to three times the impressed voltage will be readily understood, when we consider that. the t o' condensers charge in parallel with the ource and then discharge in series with each other and in series with the source. This gives a maximumyoltage three times the maximum impressed voltage. The charge may be continuously held at substantially this maximum value by the condenser Which shunts the load.

Fig. 11 shows a system equipped with an asymmetric conductor which, so far as I am aware, possesses novel features and quali- The asymmetric conductor consists" of a refractory s ick 94 consisting of oxids of the rare metals or of other .metals of that general nature heretofore employed in the so-called N ernst glowers. .Such materials are substantially non-conducting at ordinary temperatures and may easily be rendered conductive by heating with a flame or in any other well known manner, and will thereafter transmit current and attain a bright incandescence. The glower is illustrated as provided wit-h the usual form of resistance ballast 95. I

I have discovered the important fact that such glowers not only emitlight but also emit energy of such a nature that it renders the adjacent space conductive for current. This conductive region extends outward for a distance of only a. few milli-meters from the incandescent glower. In fact, it is confined principally or wholly to the end of'the glower which is negative at the particular instant. Thus, if the glower is operated on alternating current, the copductive region shifts from one end of the glower to the other at each half-cycle, I o

In the drawing I have illustrated conductive plates or points 96 and'97 held near the respective ends of the glower in such aposition as to readily'transmit current across the gaps which are made conductive by the current. As the result, the intermediate load terminal 98 is maintained at a constant negative potential with respect to the alternating current 'main'99. The system is analogous to the vapor tube systemhepetofore described and illustrated. in Fig. 4 difi'ering therefrom only in the different character of the asymmetric conductor used.

Although I have above described my basic invention as applied to single-phase appason skilled in'the art that it isalso appli cable to poly-phase systems, and that many modifications and species will readily sug-' gest themselves. Although I have not deemed it expedient to describe such polyphase systems at length, I have illustrated in F ig. 12 one arrangement which possesses certain novel characteristics The electrolytic cell 100 is provided with three aluminum electrodes, 101, 102 and 103 whichhave a large electrostatic capacity, and which are connected to.onev terminal of a three phase source 104.. The neutral of the source is connected through a suitable consumption circuit 105 with an iron or carbon electrode 106, immersed in the electrolyte. The aluminum electrodes cannot transmit current 1 to the electrolyte because of the protective action of the insulating films formed thereon by the electrolyte, but they do have power to take up an electrostatic charge, and to render the electrolyte at an appreciable negative potential with respect to the neutral of the three-phase source. As the result, current will flow from the neutral of f the source through the l'oadto the electrolyte and then back to the source by way of the particular aluminum electrode,or electrodes which happen at the instant to be ofthe proper polarity to receive the current.

In a single-phase electrolyte condenser,

the negative charge may be considered as sent back and forth from one electrode to the other, but in a poly-phase condenser as above described the negative electrostatic charge in the electrolyte shifts from one electrodeto the otherwith a speed corresponding to the frequency of the source, and thus rotates in synchronism therewith. I contemplate the use of this rotating electro-. static, charge for various electrotechnical applications, andI have hereinafter indicated some of themathematical relations thereof.

The sum of the-coulomb charges on the three platesis constant, and is equal to the maximum charge capable of being held by the cell with a given impressed pressure. This maximum charge does not collect at a time when the pressure across two of the plates is a maximum, as in case of a singlephase condenser, but it collects when two of the three plates are at an equal positive potential with respect to the third plate.

The constant coulomb charge is equal to cov /2E of one of the three smaller plates, the delta alternating currentp' .where C is equal to the electrostatic capacity nd' 1i 1 "is;

70 ratus, it will, of course, be obvious to a persaid asymmetric conductor.

pressed on the cell. The unidirectional and constant pressure set up between the electrolyte and the neutral point of the threephase circuit is theoretically equal to the maximum value of the star voltage of the circuit. 7 I

If one of the three electrodes be disconnected from the circuit the constant unidirectional pressure drops to pressure. The total energy stored in the condenser is constant at all times, and is equal to where C is the capacity of one of the plates and E is the delta pressure impressed the cell.

What I claim as new and desire to secure by Letters Patent of the United States, is,+

1. The combination with a source of alternating current, of a condenser connected to receive energy therefrom, stationary means for preventing deliverance of energy to said condenser during alternate half waves of said source a load circuit and connections between said source, said condenser and said circuit, whereby a potential difl'erence greater than that of said source is applied to the circuit.

2. The combination with a source of alternating current, of a condenser receiving energy therefrom, an asymmetric conductor connected in series with said condenser, and a unidirectional load circuit connected across 3. The combination with absourc of alternating current, of a condenser, stationary means for deliver'ng energy to said condenser during each alternate half wave of said source and for preventing the deliverance of energy thereto during the remaining half wave, and a load circuitrec'eiving energy by way of said condenser at a maximum potential higher than the maximum potential of said source.

l. The combination with a source of alternating current, of means for accumulating an appreciable electrostatic charge, a load stationary means of negligible circuit, and

reactance for conducting said charge to said load as unidirectional current. v

5. The combination with alternating current mains, of an asymmetric conductor and means, for storing an electrostatic charge connected across said mains and tending to maintain a constant difference of potential across said storing means, and translating devices connected: to receive energy from said storing means by way of said alternating current mains.

6. The combination with alternating'current mains, ofa' condenser. connected to take energy therefrom, means for limiting the delivery of energy to said condenser, said means having greater conductivity in one direction than in the other, and a translating rent mains, of a conductive path therebetween including a condenser, and a second path common to a part of said conductive,

path and including translating devices, the places of connection for said translating devices being at parts of said conductive path having a maximum potential higher than the maximum potential across said. alternating current mains; Y

8. The combination of an alternating current source, an asymmetricconductor con nected to said source, "a condenser in circuit therewith,- and a load circuit receiving energy by way of said condenser at a potential higher than the maximum potential-of said alternating current source.

v 9. The combination with alternating current mains, of an asymmetric conductor, and means for storing an substantially the otential of said source, said conductor an storing means being connected across said mains, and a load circuit connected across said asymmetric conductor.

electrostatic charge at '10. The combination of a source of alternating current, condensers for storing electric energy from said source in a plurality of places, asymmetric means for preventing the return of said'energy to said source, and a load circuit connected to receive the stored energy from one of said condensers as a unidirectionalflow boosted in voltage by energy from another of said condensers.

In witness whereof, I have hereunto set my hand this 13th day of October, 1906.

CLARENCE IRVING ZIMMERMAN.

Witnesses:

JESSIE B. MoVnAN, MICHAEL J. NOONAN.

I tori'cit'ions in Letters Pateiit No. 1,099,960;-

It it; hereby certifiefi that in Letters Patent No. 1,099,960, granted June 16., 1914, uponthe application of Clarence Irving Zimmerman, of Niagara F ails, New York, for an improvement in Electric Converters, errors appear in the printed specification requiring correction as follows: Page 3,- linei2el, before the word substantially -insert the ord of} page 7, line li for the word simusoidai read sinusoidal; same page, line 28, after the Word maximum insert the words impressed wltdge; and that the eaid Letters ]E "atent should be read with these corrections therein that 1 the samemay conform to the record 0f the casein the Patent Ofiiee. v

Signed and sealed this 7th day of July, A 1)., 19 4.

R. F. WHITEHEAD, Aothzg Ummniasioner of Patents.

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