US3246230A

US3246230A - Voltage multiplication apparatus

Info

Publication number: US3246230A
Application number: US177660A
Authority: US
Inventors: Marshall R Cleland
Original assignee: Radiation Dynamics Inc
Current assignee: Radiation Dynamics Inc
Priority date: 1962-03-05
Filing date: 1962-03-05
Publication date: 1966-04-12
Anticipated expiration: 1983-04-12

Description

April 12, 1966 M. R. CLELAND VOLTAGE MULTIPLICATION APPARATUS '7 Sheets-Sheet 1 Filed March 5, 1962 NEQ T April 12, 1966 M. R. CLELAND VOLTAGE MULTIPLICATION APPARATUS '7 Sheets-Sheet 2 Filed March 5, 1962 April 12, 1966 M. R. CLELAND VOLTAGE MULTIPLICATION APPARATUS 7 Sheets-Sheet 3 Filed March 5, 1962 CSY/ csxa

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W 2 2 \r 2 F I m M x M R m C C C N J Tr. A A vow N C E C X N NM C r1 B {H M H I An MT Mr M R N 0 6 B 1 TV. N M 2 1 m H m g\ .R B B R P m w April 12, 1966 M. R. CLELAND VOLTAGE MULTIPLICA'IION APPARATUS 7 Sheets-Sheet 4 Filed March 5, 1962 April 12, 1966 M. R. CLELAND VOLTAGE MULTIPLICATION APPARATUS 7 Sheets-Sheet 5 Filed March 5, 1962 April 1966 M. R. CLELAND 3,246,230

VOLTAGE MULTIPLICATION APPARATUS Filed March 5, 1962 7 Sheets-Sheet 6 can c5242 55x3 0x1\ fi RNA 7 Rwz RAB 9 RNB 0)! IV I 023 J jicszz c523 April 12, 1966 M. R. CLELAND 3,246,230

VOLTAGE MULTIPLICATION APPARATUS Filed March 5, 1962 7 Sheets-Sheet 7 United States Patent 3 246,230 VOLTAGE MULTIILICATION APPARATU Marshall R. Cleland, Huntington Station, N.Y., assignor to Radiation Dynamics, line, Westbury, N.Y., a corporation of New York Filed Mar. 5, 1962, Ser. No. 177,660 18 Claims. (Cl. 321-) This invention relates to voltage multiplication apparatus, and more particularly to voltage multiplication apparatus which provides a high voltage DC. output potential.

Among the several objects of this invention may be noted the provision of voltage multiplication apparatus which operates with increased efficiency to convert relatively low voltage A.C. power to a high voltage DC. output potential at improved DC. output current levels and reduced voltage ripple; the provision of such apparatus which is compact and has reduced insulation requirements; the provision of apparatus of the class described which has decreased cooling requirements and can utilize polyphase A.C. power sources which'operate at relatively low frequencies; the provision of voltage multiplication apparatus which may employ an A.C. power source of lower potential and has reduced power dissipation; the provision of apparatus of the class described which more efficiently utilizes rectifier-s of decreased ratings; the provision of such apparatus which may conveniently incorporate an accelerator tube for the production of high energy ion or electron beams;

3,246,230 Patented Apr. 12, 1966 1 units are energized or driven from a single relatively low or the inductor itself may be part of the tank circuit of an and the provision of voltage multiplication apparatus which is reliable in operation and economical in cost. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illus trated,

FIG. 1 is an exploded side oblique view, partially diagrammatic, of a portion of one embodiment of voltage multiplication apparatus of my invention;

FIG. 2 is a cross section taken on line 22 of FIG. 1;

FIG. 3 is a schematic circuit diagram illustrating certain principles of the present invention;

FIGS. 4 and 5 are views respectively similar to those of FIGS, 1 and 2, but of a second embodiment of my invention;

FIGS. 6 and 7 are views respectively similar to those of FIGS. 1 and 2 of another embodiment of this invention but with the grounded container and the intermediate electrodes omitted in FIG. 6; and

FIGS. 8 and 9 are views respectively similar to those of FIGS. 1 and 2 of still another embodiment of my invention, but with the grounded container and intermediate electrodes omitted in FIG. 8.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Several types of apparatus are now utilized in generating high voltage D.C. potentials in the order of a million and more volts. One of these types of apparatus, which is particularly advantageous in suplying these high D.C. voltages, especially at relatively high current levels in the order or 1 to 10 or more milliamperes, is the cascaded rectifier, such as is disclosed in my coassigned US. Patent 2,875,394. In this type of voltage multiplication apparatus, a number of rectifier units are serially connected so that the sum of their respective DC. output potentials is supplied at high voltage D.C. terminals, and all rectifier R.-F. oscillator or amplifier, the capacitance of the shell electrodes and associated components providing at least a portion of the capacitance parameter of an LC circuit resonant at the frequency of the A.C. power source. One of the difiiculties encountered with voltage multiplication apparatus of this and many other types is the minimizing of power losses .and generally increasing the efiiciency of operation.

In accordance with the present invention, voltage multiplication apparatus is provided which greatly improves the operational efiiciency, minimizes power losses, permits the use of lower voltage A.C. power sources and more compact structural dimensions, as well as markedly reducing the insulation requirements. In essence my invention comprises a plurality of rectifying modules, each having a rectifier connected between a positive and a negative terminal. These module terminals are series-connected between a pair of high-voltage D.C. terminals, and each module further includes at least two corona shields with an inductor connected therebetween. A source of A.C. power is connected to at least two metallic electrodes to establish an A.C. electric field therebetween. The corona shields and the rectifying modules are positioned in this A.C, field so that electrical energy is capacitively coupled to said corona shields to establish substantially equal A.C. potentials across each of the inductors and each inductor is connected to energize its respective rectifier unit. Preferably, each of the rectifying modules constitutes a portion of a series LC circuit including the interelectrode capacitances between the metallic electrodes and the respective corona shields. By maintaining the frequency of the A.C. power source at approximately the natural resonant frequency of these LC circuits, the magnitude of the A.C. voltage developed across each of the inductors will substantially exceed that of the A.C. power source.

' Referring now more particularly to FIGS. 1 and 2, an electrically grounded, heavy steel, cylindric, gas-tight, pressure container is indicated at numeral 1. Enclosed within this container are a number of identical rectifying modules, each indicated generally by reference characters RMA, RMB and RMN. Each of these rectfier units includes an inductor, such as indicated at IA, 1B and IN,

, respectively connected between two pairs of commonly connected arcuate metallic corona shields CSAl, CSA2; CSBl, CSBZ; CSCI, CSCZ; CSMI, CSM2; and CSNI, CSN2. It will be understood that single or common corona shields may be used instead of pairs of shields. Reference characters CXA, CXB, and CXN indicate the interelectrode capacitances between the opposed pairs of corona shields. Each of these rectifying modules RMA, RMB and RMN further includes a rectifier, such as a diode, DA, DB and DN connected in shunt with its respective inductor IAIN and the interelectrode capacitances CXA-CXN. As each pair of corona shields CSAl, CSALCSNI, CSN2 is respectively commonly connected to opposite electrodes of the rectifier units DA-DN, successive pairs of corona shields constitute opposite polarity terminals of the respective rectifying modules. For example, the negative terminal of rectifying module RMA is CSAI, CSA2, while the positive terminal thereof is CSB'l, CSB2. As the CSBI, CSB2 shields constitute the negative terminal of the rectifying module RMB and C801, CSC2 are the positive terminal thereof, these terminals of the rectifying modules are seen to be connected in series or cascade between a pair of high voltage D.C. terminals HVl and HVZ. The latter terminal is electrically connected to the grounded container 1, while the former high voltage terminal HVl is electrically connected to a dome-shaped metallic electrode HVD. Preferably R.-F. chokes RFC are series-connected in the high voltage D.C. circuit to inhibit the flow of RF. in any electrical load to be energized by connection to terminals HVl and HV2. A DC. blocking capacitor, as indicated at CA, CB and CN, is also included in each of the rectifying modules RMA-RMN of this embodiment of FIGS. 1 and 2, each of which is serially connected with the respective module inductor IAIN. The A.C. impedance of each of these capacitors CA, CB-CN is much lower than that of the respective inductors IA, IB-IN so that their parameters can be ignored in the A.C. analysis.

The assembly of the cascaded rectifying modules is positioned between a pair of spaced-apart metallic shell electrodes E1 and E2. The electrodes are connected to a source of A.C. power, such as for example an R.-F. oscillator or power amplifier capable of supplying potential of about 10,000 volts or more at a frequency range in the order of 20 to 200 kc. to electrodes E1 and E2. The electric field thus established between electrodes E1 and E2 is utilized to drive or energize the rectifying modules RMA-RMN by applying substantially the same A.C. potential across opposed pairs of corona shields CSAl, CSA2; CSB1, CSBZ; CSCl, CSCZ; etc., via respective interelectrode capacitances CESA, CESB, CESC, CESM, and CESN. Thus A.C. power is coupled capacitively from electrode E2 to corona shields CSAl, CSA2 via the capacitance CESA therebetween. Similarly A.C. power is coupled capacitively from electrode Ell via interelectrode capacitance CESB to CSBI, CSB2. The capacitances between the electrodes E1 and E2 and the grounded container 1 are indicated at CEGl and CEG2. It will be noted that the corona shields and the shell electrodes are arranged symmetrically along the longitudinal axis of container 1, thus permitting the mounting along the central axis of an elongate accelerator tube AT (shown only in FIG. 2 so as to avoid obscuring circuit details in FIG. 1) across which the high voltage DC. potential produced by the voltage multiplication apparatus of this invention may be applied. Tube AT constitutes an exemplary load adapted to be connected across the high voltage terminals HVI and HV2.

The circuit of FIGS. 1 and 2 is shown schematically in FIG. 3, together with an exemplary source of A.C. or R.-F. power constituted by a pair of triode vacuum tubes VM and VTZ connected in a push-pull amplifier circuit and excited by a generator GN, which may be any conventional R.-F. signal generator, such as an oscillator. The usual D.C. plate voltage for the anode-cathode circuits of VTl and VT2 is supplied through the R.-F. chokes RFCI and RFC2, as indicated at B+, the negative teranimal of the plate voltage supply being grounded as is customary. The control grids are connected to respective terminals of generator GN through two similar parallel RC circuits or grid-leak networks RCA and RCB which develop grid bias so as to achieve the high tube efficiency of class C operation. The anodes of VT1 and VT2 are connected by

conductors

3 and 5 to the shelf electrodes E1, E2; these electrodes, the corona shields and rectifying modules constituting an LC tank circuit for this push-pull power amplifier. It will be noted that although only two rectifying modules RMA and RMB are illustrated with their associated corona shields in FIG. 3, the others are all effectively connected in parallel therewith relative to the A.C. drive as described above.

Operation of the apparatus of this embodiment is as follows: Assuming that the output A.C. potential impressed across El, E2 via

conductors

3 and 5 is 10,000 volts, A.C. power is coupled to RMA-RMN via the interelectrode capacitances CESACESN. For maximum effectiveness in producing the maximum DC. potential at HVl, HV2, the maximum A.C. voltage should be applied across each rectifying module. This is accomplished in accordance with the present invention inasmuch as each rectifying module constitutes a portion of a series LC circuit which includes the inductance of the inductor, such as IA, and the two interelectrode capacitances CESA, CESB. The interelectrode capacitance CXA between the opposed pairs of corona shields CSAl, CSA2 and CSBl, CSB2 and the inherent capacitance between the electrodes of the rectifying unit DA are efiTectively in parallel with the inductor IA. The inductive and capacitive parameters of these circuit components and the frequency of the A.C. power source are chosen so that the later approximates the resonant frequency of these series LC circuits, each including a rectifying module and its respective associated capacitances. As the capacitors CA, CB-CN function simply to block D.C. they will have a very low impedance at the frequency of operation of this voltage multiplication apparatus.

By applying an A.C. voltage of, say, 10,000 volts across electrodes E1 and E2 by means of the power amplifier including VTl and VT2, a voltage of 50,000 volts or more is developed across each of the inductors IA, IBIN. This amount of voltage gain between the applied across E1, E2 and that developed across IA, IB-IN is a function of the Q of the series resonant LC circuits described above. If there is an effective Q of 5, for example, under usual circuit loading conditions, there will be a voltage developed across each of the inductors of the respective rectifying modules that is five times that of the voltage applied across E1 and E2. Similarly, with an applied voltage of 10 kv. across E1 and E2 and a Q of 10, a voltage of about kv. will be developed across each of the inductors.

It will be noted that although a push-pull configuration vacuum tube power amplifier is illustrated as a source of A.C. power, other equivalent power sources such as semiconductor transducer units and mechanical generators may be employed. Also, as described and illustrated in my coassigned copending application Serial No. 49,773, field August 15, 1960, the source of A.C. power may be a self-excited single-ended or push pull oscillator in which instance the grids, or equivalent electrodes of transistor or semiconductor transducers, are excited by a signal or signals fed back in proper phase relationship (by means of probes, etc., such as shown in the aforesaid patent application, but preferably positioned adjacent respective corona shields, e.g., CSMI, and CSNl, rather than electrodes E1 and E2 inasmuch as the R.-F. potential across any opposed set of corona shields is greater than across E1, E2). Further, it will be understood that instead of utilizing the L and C of the assembly of the electrodes E1 and E2 and the rectifying modules as the tank circuit of the amplifier or oscillator, this assembly can be driven or excited from a separate tank circuit or other A.C. generator. It is preferred that the A.C. power source be a relatively low impedance source. The capacitances CEGl and CEG2 can be conveniently adjusted by varying the spacing between the grounded container 1 and the electrodes E1, E2 to adjust the impedance matching, or additional separate capacitors could be utilized between ground and the anodes of VTl and VT2 for this purpose.

As the voltage differential between the grounded container and electrodes E1, E2 is quite low, the spacing between these elements may be small and the insulation requirement-s reduced. Also, as circulation of extremely high R.-F. currents and power losses are minimized, the heat generated by the voltage multiplication apparatus of my invention is lessened and this simplifies the design and construction of this apparatus, and decreases the cost of cooling accessories, etc. Thus, a physically quite compact generator with a minimum of expensive cooling equipment can be constructed that'will develop extremely highvoltages eg', on the order of 5 or 6 mv. or higher, at substantial current levels in the order of several milliamperes and more. 1

The second embodiment of voltage multiplication apparatus of this invention is illustrated in FIGS. 4 and 5 and is quite similar to that of FIGS. 1 and 2. The principal difference between the two embodiments is that a full-wave recti-fier'configuration is utilizedin each rectifying module (RMAl and RMNI in FIGS. 4 and 5), rather than the half-wave rectifier arrangment employed in FIGS. 1 and 2. Thus in FIGS. 4 and 5 an exemplary rectifying module RMAI includes inductor IA connected between the two pairs of corona shields CSAI, CSA2 and CSBl, CSBZ, the former spaced adjacent metallic electrode E2 while the latter is positioned close to electrode E1. The full-wave rectifier includes rectifying units DAL DA2, DA3 and DA4 connected in a bridge configuration with the input junctions connected across IA and'the output junctions constituting the terminals of the rectifying modules as indicated at 7 and 9. Another identical rectifying module RMNI, analogously referenced, is also shown in FIG. 4 having its

output terminals

10 and 12 serially connected in the D.C. high voltage circuit.

The operation of the voltage multiplication apparatus of this embodiment is essentially the same as that de: scribed above in regard to FIGS. 1 and 2 'with only minor differences. For example, as the full-wave rectification reduces the ripple; amplitude of the rectified D.C., the,.R. F. chokesR-FC of FIG. 1 are not needed in this embodiment. The D.C. blocking capacitors CA, CB and CN are also unnecessary in this embodiment and accordingly are omitted, Also, as indicated above, the corona shields are not utilized as the terminals. of the rectifying modules in this .second embodiment, although these coronatshieldsjn :both embodiments do serve the dual functions of providing corona protection as well as constituting 'one' electrode 'of the capacitance which serves to couple A.C. power from-the shells'El and E2 tothe rectifying modules. V,

"Thethird embodiment of this invention, illustrated in FIGS hfand .7, is again quite similarto those described above, One essential 'andimportant distinction is that 'a three-phase A.C. power sourceis utilized to drivejor energize three symmetrically disposed metallic electrodes E3, E4 and E5,"eacl1" connected to one phase of. the threephase power supply. Positioned adjacent and respectively; equidistantly spaced from these three electrodes are sets of three arcuate coron'a'shields CSXl, CSYl, CSZl; CSXZ, CSY2, CSZ2; and CSX3, CSY3, CSZ3. These sets, of .three corona rings, three inductors IX, IY and IZ, and, six rectifierunits'DXI, DXZ, DY1, DY2, and DZ1 and DZZ comprise an individaul rectifying module of this embodiment, there being any desired number of such modules aligned along the longitudinal axis of tank land concentrically relative to the axis accelerator tube 'AT. The terminals of, each of these rectifying modules are serially connected to provide a high D.C. potential (which is thesum of eachof the rectified output potentialsof each of the modules) at the D.C. high voltage terminals of the voltage multiplication.apparatus. r The inductors, IX, -IY and IZ are commonly connected at 'a metallic ring RN2, the other terminals of these three inductors being respectively connected to corona shields. CSXZ, CSY2 and C822. The three rectifier units DXl, DY1 and DZ1 are respectively interconnected between corona shields CSXl, CSYl and C521 and a common connection to another concentric metallic ring RN1. Identical interconnections are made between CSX3, CSY3 and CSZ3 with the remaining three rectifier units DX3, DY3 and DZ3 and between these rectifier units and a third ring RN3. I It will be noted that each of the two sets of three rectifiers (DX 1 DY 1, DZl and DX3, DY3, DZ3) and the three inductors (IX, IY, IZ)

6 are each interconnected in a Y configuration. The three corona shields CSX1, CSX2 and CSX3 are commonly electrically connected and could be constituted by a single arcuate section if desired. Shields CSYI', CSY2 and CSY3, as well as CSZI, CSZ2 and CSZ3, are respectively similarly electrically commonly interconnected. Ring RN1 constitutes the negative terminal of this exemplary rectifying module, while ring RN3 constitutes the positive polarity terminal thereof. Ring RN1 is connected by a wire 7 to a similar ring RNA which is the positive terminal' of an identical rectifying module to the left of the one illustrated. Ring RN3 is likewise connected by a conductor 9 to an identical ring RNB which is the negative terminal of an identical rectifying module to the right of the one illustrated.

It is preferred that the inductors 1X, IY and IZ be of the solenoidal type with their axes radially positioned relativeto the central longitudinal axes of the rectifying modules so as to be parallel to the R.-'F. electric field established between the arcuate corona shields and the central ring RN2 which thereby insures uniform voltage distribution along the full length of the inductors and rectifiers. The use of the rings RN1, RN2 and RN3 is optional but preferred inasmuch as they serve to prevent R.-F. heating of resistor strings RS interconnected between grading rings of accelerator tube AT. These rings RN1, RN2, RN3 are also especially useful in the three phase embodiment, inasmuch as it provides some capacitive loading of the junction points of the floating bridge circuits.

The operation of the embodiment of FIGS. 6 and 7 is again similar to that described above, except that the rectification of out-of-phase voltages developed across IX, IY and IZ is accomplished by a three-phase bridge. Again the A.C. potentials developed across these inductors is substantially greaterthan that applied to' elec-' trodes E1, E2 and E3 because of the series LC circuit relationship described above. The use of a three-phase configuration, as illustrated in this embodiment and in the succeeding one, provides a more eificient use of rectifiers wherein smaller rating rectifiers maybe utilized and also permits operation-at lower frequencies of the A.C. power supply.

Still \another embodiment of my invention is illustrated in FIGS. 8 and 9. As in the preceeding embodiment, a three-phase A.C. power source is employed to drive the three elongate, arcuate-in-crosseection, metallic electrodes E3, E4 and E5. A typical three-phase A.C. power supply is indicated generally at ACP interconnected by

leads

11, 13 and 15 to these three electrodes. The only significant differences between this and the preceding embodiment are the delta configuration of the three interconnected inductors IXY, IXZ and IYZ, and the elimination of the inner shielding rings RN1, RN2, and RN3. The Y-connected rectifiers DX1, DY1 and DZ1 have a common junction as indicated at 17, While the Y-connected rectifiers DX3, DY3 and DZ3-ha1ve a common junction at 19, which junctions 17 and 19 respectively constitute the negative and positive terminals of this exemplary rectifying module. These terminals of this one module are serially connected to the terminals of adjacent identical rectifying modules.

The illustrative three-phase power source ACP includes any customary A.C. or R.F. generator GN1 having two phase-shifter networks PS1 and PS2 (to effect a-+l20 and a 12() phase shift relative to the time base of the drive signal present on conductor 17) respectively interconnected to the control grids of vacuum tubes VTS and VT3. Conductor 17 is connected to the grid of a third amplifier tube VT4, the cathodes of thesethree tubes being connected via resistors R1, R2 and R3 to ground, and by means of

wires

19, 21 and 23, and the usual grid-leak networks GL1, GL2 and GL3, t the control grids of a three-phase power amplifier stage in- 7 cluding vacuum tubes VT6, VT7 and VT8. The anodes of VT3-VT5 are commonly connected to the positive terminals of a DC. plate supply, the negative terminal of which is grounded. These three tubes VTS-VTS and their associated components constitute a cathode-follower driver for the final stage amplifier VTd-VTS, the cathodes of which are commonly grounded. The anodes of these tubes VT6, VT7 and VT8 are interconnected by DC. blocking capacitors C1, C2 and C3 to

conductors

11, 13 and to supply excitation power to the driving electrodes E3, E4 and E5. The anodes of VT6-VT8 are connected by means of three additional R.F. chokes RFC6-R'FC8t0 a DC. plate voltage supply, the negative terminal of which is grounded. Three high impedance isolation chokes RFC9-RFC11 are connected from

conductors

11, 13 and 15 respectively to ground to prevent buildup of DC. potentials on these conductors due to occasional electrical discharges from the corona shields.

The operation of this FIGS. 8 and 9 embodiment is similar to that described above with regard to the other three-phase voltage multiplication apparatus.

It will be understood that although half-, fulland three-phase configuration rectifying modules and apparatus have been specifically disclosed, other polyph-ase rectifier configurations may be utilized, if desired. Also, it will be noted that any of the conventional types of rectifiers (e.g., vacuum, gas, semiconductor, dry type, etc.) may be used and that several units thereof may be interconnected to consti-mte a rectifier unit of this invention. Further, these rectifiers may be reversed in their sockets or interconnection to reverse the polarity of the high voltage D.C. terminals, if desired. Any voltage regulator circuitry may also be utilized in conjunction with the A.C. power sources employed to further enhance the voltage versus load curve or characteristics of this apparatus.

In view of the above, itwil-l be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is: v

1. Voltage multiplication apparatus comprising a plurality of rectifying modules each having a rectifier unit connected between a positive and a negative terminal, the terminals of said modules being series-connected between a pair of high voltage D.C. terminals, each module further including at least two corona shields with an inductor connected there'between, at least two metallic electrodes, a source of A.C. power connected to said electrodes to establish an A.C. electric field therebetween, said corona shields being positioned in said A.C. field whereby electrical energy is capacitively coupled to said corona shields to establish substantially equal A.C. potentials across each of said inductors and each inductor is connected to energize its respective rectifier unit.

2. Voltage multiplication apparatus as set forth in claim 1 in which each of the rectifying modules constitutes a portion-of a series LC circuit including the interelectrode capacitan-ces between themetallic electrodes and the respective corona shields and the frequency of -said A.C. power source approximates the natural resonant frequency of said LC circuits, whereby the magnitude of the A.C. voltage developed across each of said inductors substantially exceeds that of the A.C. power source. 1

3. Voltage multiplication apparatus as set forth in claim 1 in which each of said rectifier units comprises a halfwave rectifier, and eachf'of'said inductors is respectively parallel-connectedtherewith...

4. Voltage multiplication apparatus as set forth in claim-Sin which each rectifying module further includes 8 a'D.C. blocking capacitor interconnected in a loop circuit between the inductor and the rectifier unit.

5. Voltage multiplication apparatus as set forth in claim 1 in which each of said rectifying units is a fullwave rectifier. I

6. Voltage multiplication as set forth in claim 5 in which each of said full wave rectifiers is connected in a bridge rectifier configuration having input terminals and output terminals, said inductor being connected across said bridge input terminals and said bridge output termi-j nals constitute said positive and negative terminals of said module. i v

7. Voltage multiplication apparatus as set forth in claim 1 in which said A.C. power source is a three phase A.C. power source and there are three metallic electrodes, one connected to each of said" phases, and at least three corona shields, each module including. three inductors and two sets of three rectifier units.

8. Voltage multiplication apparatus as set forth in claim 7 in which each of said sets of three rectifier units is Y-connected. I

9. Voltage multiplication apparatus as set forth in claim 8 in which said three inductor s are Y-connected.

10. Voltage multiplication apparatus as set forth in claim 8 in which said three inductors are delta-connected.

11. Voltage multiplication apparatus comprising at least two opposed metallic shells having-their respective Edges spaced apart, a plurality of rectifying modules each having a rectifier unit connected between a positive and a negative terminal, the terminals of said modules being series-connected between a pair of high voltage D.C, terminals, said modules being generally symmetrically positioned within the space enclosed by said metallic shells and about a central longitudinal axis of said opposed metallic shells, each module further including at least two corona shields with an inductor connected therebetween, saidcorona shields of each module being positioned in a plane generally transverse to said longi tudinal axis, and a source of AC. power connected to said metallic shells to establish a radial A.C. electric field therebetween transverse to said axis whereby electrical energy is capacitively coupled to said corona shields to establish substantially equal A.C. potentials across each of said inductors and each inductor is connected to energize its respective rectifier unit.

12. Voltage multiplication apparatus asset forth in claim 11 in which each of therectifying modules consti tutes a portion of a series LC circuit including them.- terelectrode capacitances between themetallic electrodes and the respective corona shields and the frequency of said A.C. power source approximates the natural resonant frequency of said LC circuits, whereby the magnitude o f'the A.C. voltage developed across each ofsaid inductors'substantially exceeds that of the A.C. p'owersourcje,

13. Voltage multiplication apparatus as set forth in claim 11 in which each of said inductors is a solenoidal coil having its longitudinal axis aligned radially relative to the axis of said metallic shells. I

14. Voltage multiplication apparatus as set forth in claimjll in which said positive and negative terminals comprise a plurality of parallel spaced apart metallic rings concentrically aligned along said longitudinal axis.

15. Voltage multiplication apparatusas set forth in claim 14 in which said A.C. power sources is a three phase A.C. power source and there are three metallic shells symmetrically positioned about said longitudinal axis, one connected to each of said phases, and at least three corona. shields, each module including three inductors and two setsof three rectifier units.

16. Voltage multiplication apparatus as set forth in claim 15 in which each of said sets of three rectifier units is Y-connected.

17. Voltage multiplication apparatus as set forth in claim 15 in which said three inductors in each module are Y-connected, and the common inter-connection thereof comprises a metallic ring concentrically aligned along said longitudinal axis.

18. Voltage multiplication apparatus as set forth in claim 16 in which said three rectifying units are Y- 5 connected and the common interconnection thereof comprises a metallic ring concentrically aligned along said longitudinal axis.

10 References Cited by the Examiner UNITED STATES PATENTS 2,214,871 9/1940 Westendorp 321-15 2,875,394 2/1959 Cleland 321-15 MILTON O. HIRSHFIELD, Primary Examiner. LLOYD MCCOLLUM, Examiner.

Claims

1. VOLTAGE MULTIPLICATION APPARATUS COMPRISING A PLURALITY OF RECTIFYING MODULES EACH HAVING A RECTIFIER UNIT CONNECTED BETWEEN A POSITIVE AND A NEGATIVE TERMINAL, THE TERMINALS OF SAID MODULES BEING SERIES-CONNECTED BETWEEN A PAIF OF HIGH VOLTAGE D.C. TERMINALS, EACH MODULE FURTHER INCLUDING AT LEAST TWO CORONA SHIELDS WITH AN INDUCTOR CONNECTED THEREBETWEEN, AT LEAST TWO METALLIC ELECTRODES, A SOURCE OF A.C. POWER CONNECTED TO SAID ELECTRODES TO ESTABLISH AN A.C. ELECTRIC FIELD THEREBETWEEN, SAID CORONA SHIELD BEING POSITIONED IN SAID A.C. FIELD WHEREBY ELECTRICAL ENERGY IS CAPACITIVELY COUPLED TO SAID CORONA SHIELDS TO ESTABLISH SUBSTANTIALLY EQUAL A.C. POTENTIALS ACROSS EACH OF SAID INDUCTORS AND EACH INDUCTOR IS CONNECTED TO ENERGIZE ITS RESPECTIVE RECTIFIER UNIT.