Lightweight high power electromagnetic transducer

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United States Patent (19) 11 Patent Number: 5,004,944 Fisher 45) Date of Patent: Apr. 2, 1991 (54) LIGHTWEIGHT HIGH POWER 9557 3/1924 United Kingdom . ELECTROMAGNETIC TRANSDUCER 2140219 11/1984 United Kingdom .

75 Inventor: Gene A. Fisher, Highlands Ranch, OTHER PUBLICATIONS Colo.

(73) Assignee: Unique Mobility, Inc., Englewood, Promising Applications of Neodymium Boron Iron Colo. Magnets in Electrical Machines (Invited), Rahman et (21) Appl. No.: 125,781 (List continued on next page.)

Related U.S. Application Data Primary Examiner-R. Skudy 63 Continuation of Ser. No. 812,306, Dec. 23, 1985, aban Attorney, Agent, or Firm-Stevens, Davis, Miller & doned. Mosher 51) Int. C. ............................................... HO2K 1/22 57 ABSTRACT 52 U.S. C. ...................................... 310/266; 310/44; An electromagnetic transducer is disclosed that is light

58 Field of Search ............... 310/266, 156, 198, 207, weight and has a high power to weight ratio, with the 310/179, 180, 181, 216, 184, 218, 44, 67 R., 64, transducer being capable of operation as an efficient 46, 65, 177, 114, 115, 261, 185, 188, 12, 13, 195, motor, alternator or generator, and being particularly 43, 45, 232, 233, 248, 52 useful, for example, in connection with self-propelled (56) References Cited vehicle applications such as passenger cars. The electro magnetic transducer can utilize a shell construction,

295,368 3/1884 Dennis . flux producing assembly, having a plurality of spaced 464,026 12/1891 Kammeyer . magnetic elements, and an armature assembly formed (List continued on next page.) by a winding arrangement of dispersed conductive ele

FOREIGN PATENT DOCUMENTS

ments which are separated by flux carrying elements which, to the extent that such flux carrying elements are 1029788 4/1978 Canada . electrically conductive, are dispersed in one, two, or 0843.866 5/1952 Fed. Rep. of Germany ...... 310/266 three dimensions to thus be dispersed-phase flux carry 1463833 9/1969 Fed. Rep. of Germany. ing elements. The armature conductors and flux carry 2925798 6/1979 Fed. Rep. of Germany . ing elements are dispersed to minimize creation of op

3031423 2/1982 Fed. Rep. of Germany ........ 310/64 posing induced currents, or eddy currents, depending 3031420 3/1982 Fed. Rep. of Germany ........ 310/64 on the effect produced on transducer operation. This 3420995 8/1985 Fed. Rep. of Germany . dispersal enables operation of the transducer at high 3224904 11/1986 Fed. Rep. of Germany. efficiency with high torque being maintained even dur 1272083 8/1961 France. ing high speed relative motion between the magentic

2243512 4/975 France . flux producing assembly and the armature with the 245646 12/1980 France. combination of high torque and high speed producing 2556897 6/1985 France . higher power per unit weight than can now know de 5694938 7/1981 Japan. VCeS.

12397.95 6/1986 U.S.S.R. . 4 Claims, 6 Drawing Sheets

CURRENT GEN

CONTROLLER / OAd

NNN ANYANNA

Miss

st NNR xNRNs,

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4,255,494 3/1981 Reen ...................................... 310/44 497,001 5/1893 Crompton. 4,264,836 4/1981 Dukshtau et al. . 1,227,185 5/1917 Neuland . 4,277,709 7/1981 Spirk. 1,456.955 5/1923 Wagner. 4,289.989 9/1981 Schibline. 2,792,511 5/1957 Horstman. 4,291,457 9/1981 Heyraud............................ 310/266 3,014, 139 12/1961 Shildneck . 4,316,111 9/1982 Merki et al. . 3,069,557 12/1962 Skelton . 4,321,494 3/1982 MacNab . 3,082,337 3/1968 Horsley . 4,327,303 4/1982 Jacobsen . 3,102,964 9/1963 Bennett et al. . 4,390,806 6/1983 O'Brien et al. . 3,121,851 2/1964 Packard .............................. 310/266 4,398,167 8/1983 Dickie et al. . 3,125,402 3/1964 Kruckenberg. 4,427,911 1/1984. Manson . 3,128,402 4/1964 Amick, Jr. .......................... 310/266 4,429,245 1/1984 Miller et al. . 3,134,037 5/1964 Upton. 4,434,389 2/1984 Langley et al. . 3,237,036 2/1966 Konig. 4,443,727 4/1984 Annen et al. . 3,275,863 9/1966 Fodor . 4,447,750 5/1984. Howlett et al. . 3,297,891 1/1967 Foran, Jr. . 4,451,749 5/1984 Kanayama ............................ 310/89 3,312,846 4/1967 Henry-Baudot. 4,453,101 6/1984 Nelson . 3,322,986 5/1967 Benatti et al. . 4,458,168 7/1984 Welburn. 3,396,296 8/1968 Esters .................................. 310/266 4,467,232 8/1984 Eichhorn et al. . 3,495,114 2/1970 Kazansky. 4,469,970 9/1984 Neumann . 3,518,469 6/1970 Storsand . 4,471,248 9/1984 Smetana . 3,538,364. 11/1970 Favereau. 4,472,650 9/1984 Advolotkin et al. . 3,566,165 2/1971 Lohr. 4,480,206 10/1984. Manson . 3,567,980 3/1971 Kreuter. 4,484,083 11/1984 Jefferies. 3,602,749 8/1971 Esters .................................. 30/266 4,484,094 11/1984 Ade et al. . 3,638,056 1/1972 Imris. 4,486,678 12/1984 Olson . 3,659,129 4/1972 Pettersen . 4,486,679 12/1984 Jones . 3,663,850 5/1972 Phelon . 4,497,001 1/1985 Hayashi et al. . 3,729,642 4/1973 Esters .................................. 310/12 4,501,980 2/1985 Welburn. 3,843,338 10/1974 Fawzy. 4,501,984 2/1985 Mishima . 3,858,071 12/1974 Griffing et al. . 4,504,755 3/1985 Semones et al. . 3,861,484 1/1975 Joslin . 4,508,998 4/1985 Hahn . 3,874,472 4/1975 Deane. 4,517,484 5/1985 Dacier . 3,882,950 .5/1975 Strohlein . 4,531,071 7/1985 Kintz, Jr. et al. . 3,908,141 9/1975 Lemonnier . 4,532,445 7/1985 Iwamoto et al. . 3,965,382 6/1976 McCroskey et al. . 4,540,906 9/1985 Blom. 4,004,167 1/1977 Meckling. 4,543,506 9/1985 Kawada et al. . 4,011,479 3/977 Volkrodt ............................. 310/81 4,547,713 10/1985 Langley et al. . 4,016,444 5/1977 Gillet . 4,550,267 10/1985 Vaidya. 4,025,831 5/1977 Webb . 4,553,075 l/1985 Brown et al. . 4,065,702 12/1977 Locker et al. . 4,556,810 12/1985 Kasper et al. . 4, 10,652 8/1978 McGahern . 4,556,828 12/1985 Thompson . 4,114,057 9/1978 Esters. 4,559,463 12/1985 Kobayashi. 4,117,519 9/1978 Shioyama et al. . 4,563,622 1/1986 Deavers et al. . 4,128,364 12/1978 Papst et al. . 4,564,778 1/1986 Yoshida ............................... 310/181 4,146,809 3/1979 Rielly. 4,564,781 1/1986 Arnegger . 4,149,309 4/1979 Mitsui . 4564,793 1/1986 Reffelt . 4,169,235 9/1979 Higuchi et al. . 4,568,862 2/1986 Tassinario .

4,233,858 11/1980 Rowlett . - (List continued on next page.)

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4,577,139 3/1986 Reinhardt et al. . European Search Report dated May 19, 1987, EP 8611 4,585,967 4/1986 Mayer et al. . 7875.

4,608,505 8/1986 Schumacher. Rare-Earth Magnets Provide Maximum Performance, 4,609,862 9/1986 Becker ................................ 310/98 K. Iijima, Tamasawa Seiko co., Ltd., Tokyo, Japan, 4,611,137 9/1986 Sutrina . JEE, J. Electron, Eng. (Japan) vol. 24, No. 247 76-8, 464,888 9/1986 Mosher et al. . 7/87.

4,618,792 10/1986 Yates. Application of Permanent Magnets in Electromechani 4,618,806 0/1986 Grouse. cal Power Converters; The Impact of Nd-Fe-B Mag 4,623,812 11/1986 Van De Griend. nets; H. Zijistra; Philips Res. Labs., Eindhoven, Nether 4,625,135 11/1986 Kasabian. lands; J. Phys. Collog. (France) vol. 46, No. C-6 3-8 4,629,917 12/1986 Brem . Sep. 1985.

4,629,921 12/1986 Gavaletz . Rare-Earth Motors Shed Their Exotic Image; B. H.

4,633,149 12/1986 Welterlin. Carlisle; Mach. Des. (U.S.A.) vol. 58, No. 2 4,636,675 1/1987 Takahashi . 18-19,22,24,26, 23 Jan. 1986. 4,636,677 1/1987 Yasuhara . Changing Permanent Magnet Technology; K. Voll 4,639,626 l/1987 McGee. brecht; IEEE, Nat. Electr. Manuf. Assoc.; Proceedings 4,639,627 1/1987 Takekoshi et al. . of the 17th Electricl/Electronics Insulation Conf, New 4,641,051 2/1987 Auinger . York, U.S.A. 376, pp. (Conference Paper).

4,644,20i 2/1987 Tani et al. . A New Concept for Urban Transit Vehicle Drives 4,647,804 3/1987 Wefel . Tested at the Hamburger Hochbahn; P. Wegener; 4,649,303 3/1987 Hirao. Brown, Boveri and Cie AG, Mannheim, Germany; Z. 4,658,165 4/1987 Vanderschaeghe. Eisenbahnwes, Verkehrstech (Glasers Ann.) (Ger 4,658,167 4/1987 Popov et al. . many) vol. 109, No. 2-3, 97-102, Feb.-Mar. 1985. 4,658,170 4/1987 Ueda . Effects on Ellipsometric Parameters Caused by Heat 4,661,737 4/1987 Barri. Treatment of Silicon Surface; S. Kondo, L. J. Hane 4,667,125 5/1987 Kaminski et al. . kamp, A. Van Silfhout; Dept. of Appl. Phys., Twente

4,670,680 6/1987 Andle. Univ. of Technol, Enschede, Netherlands, Surf. Sci. 4,672,247 6/1987 Madsen et al. . (Netherlands) vol. 65, No. 2, 633-40, Jul. 1977. 4,678,954 7/1987 Takeda et al. . Wheel Hub Motors Applied to Electric Vehicle Propul 4,682,069 7/1987 Stahl. sion; A.W. Beishline, G. S. Goldman; Gold Line Eng., 4,689,532 8/1987 Howlett . Fullerton, Calif.; Proc Intersoc Energy Convers Eng

4,695,754 9/1987 Popov et al. . Conf 14th v 1, Boston Mass., Aug. 5-10, 1979, Publ by 4,697,114 9/1987 Amemiya et al. . Am Chem Soc, Wash, DC, 1979. 4,698,538 10/1987 Yoshida . Demonstration of Inductor Motor/Alternator/Fly 4,709,179 11/1987 Banon et al. . wheel Energy Storage System; Technical Quarterly 4,714,851 12/1987 Bertram et al. . Progress Report, No. 2, Sep. 28, 1976-Dec. 28, 1976,

4,731,554 3/1988 Hall et al. . General Electric Co., Schenectady, NY. 4,734,606 3/1988 Haject. High-Speed, High-Efficiency Permanent Magnetic 4,900,965 2/1990 Fisher .................................. 30/266 Motor-Generator; A. R. Millner; MIT, Lincoln Lab, OTHER PUBLICATIONS Lexington, Mass.-Proc of the Int Workshop on Rare al., IEEE Transactions on Magnetics, vol. MAG-21, Earth-Cobalt Perm Magnets and Their Appl., 3rd. No. 5, Sep. 1985, pp. 1712-1719. Univ of CA, La Jolla, Jun. 27-30, 1978.

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It has also been heretofore suggested than an electro

LIGHTWEGHT HIGH POWER magnetic transducer could have a power to weight ratio ELECTROMAGNETIC TRANSDUCER of up to about one horsepower to one pound (see, for example, U.S. Pat. No. 3,275,863). In addition, cooling

This is a configuration of application Ser. No. 5 of a motor, to increase power handling capability, using 06/812,306 filed Dec. 23, 1985, now abandoned. a gas, liquid, or a mixture of a gas and liquid, is well FIELD OF THE INVENTION known (see, for example, U.S. Pat. No. 4,128,364). While various arrangements for electromagnetic

This invention relates to an electromagnetic trans 10 transducers have therefore been heretofore suggested ducer, and, more particularly relates to a lightweight and/or utilized, such transducers have not been found high power electromagnetic transducer capable of use to be completely successful for at least some uses, in as a motor, alternator or generator. cluding providing a lightweight transducer that is capa BACKGROUND OF THE INVENTION ble of providing high power.

In particular, the prior art does not teach the neces

Electromagnetic transducers are known for use both 15 sity to disperse the conductors to enable high speed in transforming electrical power into mechanical power operation, due, at least in part, to a widely taught theory and transforming mechanical power into electrical that the magnetic field is very low in the conductors. power. In both cases, power producing capability re With conductors built according to conventional teach sults due to relative movement between magnetic ele 20 ings, however, it has been found that torque, at constant ments and electrically conductive elements, as is well current, decreases with incerasing speed, which result is known, for example, in the application of this phenome contrary to the conventional expectation that torque non to motors, alternators and generators. would remain high as speed increases (which is the While it is well known that motor, alternator and result achieved by this invention).

generator devices can be made that are quite light in 25 SUMMARY OF THE INVENTION weight, and while at least some known lightweight devices have been capable of operation at high speeds, This invention provides an improved electromag such devices have not been capable of operation at high netic transducer that is lightweight and yet provides speeds to produce high power. For example, high high power conversion due to the high power density power density devices of 0.6 horsepower per pound of 3O capability of the transducer, with the transducer being weight are known for intermittent operation, but such capable of operation as a highly efficient motor, alterna devices are incapable of continuous operation at high tor or generator, with the transducer of this invention power densities in excess of 1.0 horsepower per pound. being capable of continuous operation at high power Known electromagnetic transducer devices have also densities in excess of 1.0 horsepower per pound. not been capable of simultaneous high speed and high 35 High power density per unit weight is effected by torque operation and/or have not provided adequate utilization of an armature assembly having dispersed efficiency in operation. In addition, prior shell construc conductors which are separated by dispersed-phase flux tion devices have not used both dispersed conductors carrying elements in a manner such that low opposing and dispersed phase flux carrying means in the armature induced currents are created, as well as low eddy cur and have, therefore, also been limited to low speed, rents, to enable operation of the transducer at high which, even at high torque, leads to low power density. efficiency with high torque being maintainable during It is also well known that an electromagnetic trans high speed operation.

ducer can include a stator and rotor arrangement, and As the armature moves relative to a magnetic flux that such an arrangement can include positioning mag producing assembly, currents (which are often referred netic elements on the rotor (see, for example, U.S. Pat. 45 to as eddy currents) are established in the electrically

the stator (see, for example, U.S. Pat. Nos. 3,102,964, conductive lead to portions of the armature and these currents heating and skin effects (which are collectively 3,312,846, 3,602,749, 3,729,642 and 4,114,057). It has known as eddy current also been heretofore suggested that a double set of polar also produce another losses). However, these currents pieces could be utilized (see, for example, U.S. Pat. No. 50 which currents are herein referredheretofore effect not

realized, opposing in

In addition, a shell type rotor has been heretofore duced currents since these currents alter the magnetic flux pattern and act to reduce the torque with speed suggested (see, for example, U.S. Pat. Nos. 295,368, increase.

3,845,338 and 4,398,167), and a double shell rotor ar with speedThis power conversion capability reduction rangement has also been suggested (see, for example, 55 due to these currents can increases are occur even when the losses acceptable, and conventional

U.S. Pat. No. 3,134,037). practice would not suggest dispersing the conductors as It has also been heretofore suggested that abundle of has been done in the electromagnetic transducer of this wires can be utilized in place of a single conductor in invention.

the armature assembly of a motor (see, for examples,

U.S. Pat. Nos. 497,001, 1,227,195, 3,014, 139, 3,128,402, 60 It is therefore an object of this invention to provide 3,538,364 and 4,321,494, as well as British Patent No. an improved electromagnetic transducer. 9,447) with such wires being stated to be for high volt It is another object of this invention to provide an age and high current usage and/or to reduce current improved electromagnetic transducer that is light flow loss, the so-called skin effect, and heating due to weight and yet provides high power so that the trans eddy currents, and with such wires being utilized in 65 ducer has high power density.

conjunction with solid and/or laminated cores (see, for It is still another object of this invention to provide an example, U.S. Pat. Nos. 3,014, 139, 3,128,402, and Brit improved electromagnetic transducer having high ish Pat. No. 9,557). power density per unit weight capability.

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It is still another object of this invention to provide an ment of the electromagnetic transducer of this inven improved electromagnetic transducer having a high tion;

power to weight ratio. FIG. 10 is a partial cut-away view similar to that of It is still another object of this invention to provide an FIG. 6 but illustrating yet another alternate embodi improved electromagnetic transducer capable of use as 5 ment of the electromagnetic transducer of this inven a highly efficient motor, alternator or generator. tion;

It is still another object of this invention to provide an FIG. 11 is a partial end view illustrating a dispersed improved electromagnetic transducer that is capable of conductor, as best shown in FIG. 4, and illustrating the continuous operation at high power densities in excess insulation layer around the conductor; of one horsepower per pound. 10 FIG. 12 is an end view similar to that of FIG. 11 but It is still another object of this invention to provide an illustrating an alternate embodiment of the armature improved electromagnetic transducer having an arma structure wherein the conductors have a coating of a ture assembly with dispersed conductors different sec flux carrying means (iron) thereon utilizable in lieu of tions of which have flux carrying elements positioned the flux carrying elements as illustrated in FIGS. 4 therebetween with the conductors and flux carrying 15 through 10;

elements being formed and positioned in a manner so as FIG. 13 is an end view similar to that of FIGS. 11 and to create low opposing induced currents. 12 but illustrating another alternate embodiment of the It is still another object of this invention to provide an armature structure wherein insulated conductors have a improved electromagnetic transducer having an opti coating of a flux carrying means (iron) thereon utiliz num thickness armature assembly which represents a able in lieu of the flux carrying elements as illustrated in balance among the effects of heat transfer to the cooling FIGS. 4 through 10;

medium, heat production from resistance heating and FIG. 14 is a partial view illustrating the use of the other sources, and torque production. embodiment of either FIG. 12 or FIG. 13 as the arma With these and other objects in view, which will ture without use of separate flux carrying elements; become apparent to one skilled in the art as the descrip 25 FIG. 15 is a partial view similar to that of FIG. 14 but tion proceeds, this invention resides in the novel con illustrating use of alternating sections of dispersed con struction, combination, and arrangement of parts sub ductors and dispersed conductors coated as shown in stantially as hereinafter described, and more particu the embodiment of FIG. 12 or FIG. 13;

larly defined by the appended claims, it being under FIG. 16 is a side sectional view of an alternate em stood that changes in the precise embodiments of the 30 bodiment of the electromagnetic transducer as shown in herein disclosed invention are meant to be included as FIG. 2, and illustrates the armature fixed to the shaft as come within the scope of the claims. may be convenient to a brush commutated transducer;

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 17 is an exploded isometric view of another alternate embodiment of the electromagnetic trans

The accompanying drawings illustrate complete em 35 ducer of this invention, and illustrates a cylindrically bodiments of the invention according to the best mode symmetric linear implementation thereof; so far devised for the practical application of the princi FIG. 18 is an exploded isometric view of still another ples thereof, and in which: alternate embodiment of the electromagnetic trans FIG. 1 is an exploded isometric view of a rotary ducer of this invention, and illustrates a flat linear imple implementation of the electromagnetic transducer of 40 mentation thereof;

this invention; FIG. 19 is a graph illustrating the relationship be FIG. 2 is a side sectional view of the assembled elec tween torque and speed for a conventional transducer b tromagnetic transducer as shown in FIG. 1, along with and for the transducer of this invention as and additional elements illustrated in block form to better FIG. 20 is a graph illustrating tested eddy current, illustrate the invention; 45 hysteresis and windage losses at different speeds of one FIG. 3 is a partial isometric view illustrating use of example of the transducer of this invention. the electromagnetic transducer of this device config DESCRIPTION OF THE INVENTION ured as a traction motor to drive a wheel of an associ ated vehicle; A novel electromagnetic transducer is particularly FIG. 4 is a partial isometric view showing the ar described herein, including alternate embodiments rangement of the dispersed conductors and flux carry thereof. It is meant to be realized that the electromag ing elements of the electromagnetic transducer shown netic transducer of this invention may be utilized as a in FIGS. 1 and 2; motor (ac or dc) or as an alternator or generator, de FIG. 5 is a diagram illustrating a typical arrangement pending on whether an electrical signal is conveyed to of a two layer winding formed by the dispersed conduc 55 the armature (commonly through a commutator or tors and illustrating the flux carrying elements posi equivalent structure) to create a force causing move tioned between turns of the windings; ment of the magnetic flux producing structure relative FIG. 6 is a sectional view taken through lines 6-6 of to the armature thus driving the shaft, or whether the FIG. 2, with the magnetic flux path in the transducer shaft is rotated to thereby cause movement of the mag also being illustrated; 60 netic flux producing structure relative to the armature FIG. 7 is a partially cut-away view similar to that of to create an electromotive force which, in turn, can FIG. 6 but illustrating an alternate embodiment of the cause movement of current along the conductors of the electromagnetic transducer of this invention; armature to be coupled from the conductors as an elec FIG. 8 is a partially cut-away view similar to that of trical signal, as is well known.

FIG. 6 but illustrating another alternate embodiment of 65 Electromagnetic transducer 35, as best shown in the electromagnetic transducer of this invention; FIGS. 1 and 2, is lightweight and yet is capable of deliv FIG. 9 is a partial cut-away view similar to that of ering high power, with the transducer being a high FIG. 6 but illustrating still another alternate embodi power density device that is particularly well suited, for

Page 12

example, for use in conjunction with self-propelled 4, different sections 85 of which are positioned between vehicle applications, such as passenger cars, although flux carrying elements 86 as best shown in FIG. 6. The the invention is not meant to be restricted thereto. conductors 84 have discrete, spaced apart active re When used for vehicle propulsion, a permanent mag gions 84A, as shown in FIGS. 4 and 5. As shown in net, hollow cylinder electromagnetic transducer 35 may FIG. 6, active regions 84A have a substantially rectan be utilized as an efficient wheel mounted traction mo gular cross-section. Between active regions 84A are a tor, and may, as indicated in FIG. 3, be mounted di plurality of discrete elongated open space areas 86A rectly at each wheel 37, adjacent to axle 39, with drive (see FIGS. 5 and 6). A flux carrying means formed of a being preferably achieved through gear reduction plurality of flux carrying members 86 of compressed mechanism 41. 10 iron powder are interposed in open space areas 86A As shown in FIGS. 1 and 2, electromagnetic trans between active regions 84A. Dispersed conductors 84 ducer 35 includes an outer cylindrical housing 43, are preferably formed from a bundle of small diameter which housing has front and rear end plates 45 and 46 copper wires 87 surrounded by insulating material 88 positioned at the opposite ends of the cylindrical hous (as best shown in FIG. 11), with conductors 84 being ing by means of snap rings 48 and 49. 15 wound into a linking pattern, as indicated by way of A shaft 51 has a central portion 52 extending through example in FIG. 5, with the opposite ends of the wire the cylindrical housing with the shaft being mounted in bundles being connected to connectors 89 extending central hubs 54 and 55 of end plates 45 and 46, respec through aperture 68 in end plate 46, as indicated in FIG. tively, by means of bearings 57 and 58 so that the central 2.

portion of the shaft is coaxially positioned with respect 20 Conductors 84, as best shown in FIG. 4, are formed to the cylindrical housing, the reduced diameter rear into a bundle throughout the armature (as by being portion 60 of the shaft is mounted in bearing 58, and the wound in a ring, for example), and each turn of the wire front portion 62 of the shaft extends forwardly of front windings has a flux carrying element 86 therebetween, end plate 45, with seal 64 being positioned in hub 54 as shown in FIGS. 5 and 6, with a typical winding, adjacent to bearing 57. 25 which constitutes a structurally integral annular wind

As also shown in FIG. 2, blower 65 is positioned ing structure, being conceptually illustrated in FIG. 5. adjacent to back, or rear, end plate 46, which plate includes offset air intake aperture 66 and a plurality of in Fluxpart), carrying elements 86 are preferably iron (at least and extend between the active region or length exhaust apertures 67 spaced about and near the periph 84A of conductors 84. Elements 86 have radially inner ery of the end plate. When so used, the transducer thus 86B and radially outer

operates in a gas (air) medium (as opposed to a fluid 5). Conductors 84A to86C elongated edges (see FIG. connect the active lengths of medium which could include oil or the like, for exam each other in an appropriate pattern, ple, as do some known transducers). In addition, an winding as shown, by way of example,such in as a wave

FIG. 5. The arcuate aperture 68 is positioned to allow armature flux carrying elements 86 are preferably dispersed conductor connections through end plate 46. 35

As best shown in FIG. 2, rotor 70 has a double shell phase flux carrying members to handle the high fre configuration provided by inner and outer spaced cylin induced magnetic quency currents field reversals with low opposing and low eddy current losses. Because drical portions, or walls 72 and 73 which extend nor iron is electrically conductive, mally from mounting disk 75 so that cylindrical portions avoid (or at least minimize) theit creation must be dispersed to of opposing 72 and 73 are coaxial with, and inside, cylindrical hous induced currents. It has been found that a suitable ing 43 and define an annular gap 72A therebetween. carrying element 86 can be pressed from fine (10-100flux m Mounting disk 75 has an annular mounting portion 77 which is received on splined portion 78 of shaft 51 in kron) iron powder previously reactively coated with phosphate insulation and using "B" stage epoxy and wardly of bearing 57.

Inner cylindrical portion 72 or rotor 70 has magnetic 45 waxByasproviding binders.

conductors comprising a plurality of elements 80 mounted thereon, which magnetic elements small diameter wires with dispersed-phase flux carrying are shown to be permanent magnets (but electromag elements between turns of the wires, opposing induced nets could be utilized, if desired). Cylindrical portions currents are minimized sufficiently 72 and 73 are formed of highly magnetically permeable so as to allow opera tion of the electromagnetic transducer with low hysteresis loss magnetic material (such as iron and at high torque with such operation being at high speeds or steel, for example), and mounting disk 75 is formed of ble conducta non-magnetic material (such as plastic or aluminum, for at high efficiency. In a working embodiment, a sta example), while magnetic elements 80 are high strength tionary armature shell incorporating windings of cop permanent magnets, which magnets are preferably per and powdered iron bars to carry the magnetic flux, formed of neodymium boron ferrite (NdFeB), but may 55 and impermeated with glass reenforced novolac epoxy also be formed of barium ferrite ceramic (BaFe Ce the insulation material cast as a binding agent 180 between ramic), samarium cobalt (SmCo), or the like. windings and bars, has been successfully utilized. Armature 82 comprises an annular member at least In this invention when used as a motor, at constant partially disposed within gap 72A and is fixed with current, it has been found that the torque output can be respect to housing 43, and is mounted on rear end plate maintained nearly constant even with increases in rotor 46, as indicated in FIG. 2, so that rotor 70 rotates rela speed, as illustrated in FIG. 19 by line a. This is quite tive to armature 82 (as well as to housing 43). Armature unlike prior art devices wherein torque was found to 82 is thus a stationary cylindrical shell element that drop off rapidly with increased speed when solid bars extends through the length of cylindrical housing 43 were utilized as conductors and as flux carrying ele between the inner and outer cylindrical portions 72 and ments, as illustrated in FIG. 19 by line b. The combina 73 of the rotor. tion of high torque and high speed, made possible in the It is important to this invention that armature 82 electromagnetic transducer of this invention, produces include dispersed conductors 84, as best shown in FIG. high power density.

Page 13

As shown in FIG. 6, armature 82 (formed by the the principal component of the armature with the wind dispersed conductors 84 and flux carrying members 86) ing consisting of bundles of separate conductors (which are closely spaced with respect to magnets 80 posi are referred to herein as dispersed conductors), with the tioned about the inner cylindrical wall 72, and also use of dispersed conductors of fine wire permitting high closely spaced with respect to cylindrical wall 73, with speed rotation of the rotor when used in conjunction walls 72 and 73 providing inner and outer return paths, with dispersed-phase flux carrying elements. respectively, for the magnetic flux. Some typical flux The use of multiple, parallel extending, insulated paths have been illustrated in FIG. 6. As shown, these conductors to reduce heating losses at high currents has flux paths are loops each of which penetrates the arma been heretofore suggested (see, for example, U.S. Pat. ture twice passing principally through the flux carrying 10 No. 497,001), and it is well known in the motor art as a members 86. The flux carrying members thus allow a method to reduce skin effect losses in motors. Skin thick armature to maintain a high flux density which is effect, however, causes losses at load only, whereas essential to high togue. eddy current losses, which would be experienced when As indicated in FIG. 7, the electromagnetic trans known devices are rotated at high speed, occur at no ducer may also be configured by placing magnets 80 on 15 load. This distinction is as to the mechanism of the outer wall 73 (rather than on inner wall 72). As indi effect.

cated in FIG. 8, the electromagnetic transducer may In the case of conductors of large cross section or also be configured by placing magnets 80 on both inner conductive flux carrying elements of large cross sec and outer walls 72 and 73. tion, as used at least in some prior known devices, as the As indicated in FIG. 9, an armature 82 can also be 20 frequency of the magnetic field reversal increases, the provided at both sides of magnets 80. In addition, while magnitude of the induced currents in the bars increases, not specifically shown, it is also to be realized that the and the induced currents react with the magnetic field electromagnetic transducer could be configured by to create a resisting torque which opposes the increase placing additional layers of armature-rotor elements of rotational speed. Thus, known shell type devices are radially inwardly and/or outwardly of that shown in 25 inherently limited to low speed by the reaction torque, the drawings. While flux carrying members 86 in the and cannot be rotated at high speed and are therefore, above embodiment are rectangular in cross-section, the unlike the device of the present invention, not suitable, flux carrying members may also be configured by utiliz for example, for use as traction motors in most practical ing a non-rectangularly shaped member such as, for applications.

example, an I-shaped member 91 (as indicated in FIG. 30 When used as a motor, a means to displace (i.e., ro 10) having dispersed conductors 84 extending therebe tate) the magnetic field relative to the armature at high tween. speed must, of course, also be provided so that electric The armature can also be configured as shown in power can be converted into mechanical power in a FIG. 12 such that flux carrying elements 93 are formed manner similar to that used by known motors. As indi as a coating of highly permeable magnetic material 35 cated in FIG. 2, this can be accomplished by connecting (such as iron) on some or all of the dispersed conductors leads 97 between connectors 89 of armature 82 and 94. As indicated in FIG. 13, conductors 94 can also current generator and controller unit 98 so that unit 98 have an insulation layer 95 thereon so that insulation provides current to conductors 84 to cause rotation of layer 95 is between the conductor and the flux carrying rotor 70, with rotation of rotor 70 causing rotation of element. In either case, an insulating layer 96 covers the shaft 51 to drive a load 99.

flux carrying element (unless it is, of itself, electrically When used as an alternator or generator, actuator 99 non-conductive). causes rotation of shaft 51 which rotates rotor 70 to When the flux carrying elements are formed as coat induce a voltage on conductors 84 and thereby gener ings on the dispersed conductors (as indicated in FIGS. ates electrical current flow from conductors 84 to a load 12 and 13), the flux carrying bars (shown in FIGS. 4 45 98. While not specifically shown in FIGS. 1 through 15, through 10) need not be utilized. The dispersed conduc it is to be realized that the current generator and con tors 94 with the flux carrying elements of the armature troller unit (or alternately the armature) includes neces (as indicated in FIG. 14) or can be alternated with dis sary electric commutation devices, including those de persed conductor sections 85, i.e., dispersed conductors vices wherein commutation is performed electronically having no flux carrying element coating thereon (as 50 (as in a brushless DC motor, for example), as well as indicated in FIG. 15). devices which employ rectifiers instead of commutation Powdered iron utilized as flux carrying elements 86 (as is often used in power generating applications). (as indicated in FIG. 6) provide three-dimensional FIG. 16 illustrates an embodiment of the electromag phase dispersion, while flux carrying elements 93 netic transducer of this invention in which armature 82 coated on the dispersed conductors (as indicated in 55 is connected with shaft 51 by mounting disk 101, and FIGS. 12 and 13) provide two-dimensional phase dis inner and outer cylindrical walls 72 and 73 are fixed to persion (iron lamination bars, on the other hand, when housing 43. In this embodiment, the armature thus be sued as flux carrying elements provide only one comes the rotor with electric power being communi dimensional phase dispersion). cated with the armature by means of brushes 102 slip The electromagnetic transducer of this invention thus rings (not identified in FIG. 16) (with brushes being includes a magnetic flux producing assembly (having at utilized in the case of a DC machine, and slip rings least one pair of poles which can be embodied by using being utilized in the case of an AC machine). The em permanent magnets or electromagnets), and an arma bodiment shown in FIG. 16 is preferred for some appli ture assembly (which intercepts the magnetic flux pro cations, particularly in the case of a DC commutated duced by the magnetic flux producing assembly and has 65 machine.

an alternating structure of conductive windings and flux The transducer of this invention has a significant carrying elements, which flux carrying elements can be advantage over a conventional motor by utilization of a referred to as armature iron). A winding can be used as minimum amount of iron which undergoes flux rever

Page 14

sal. That is, only the iron in the flux carrying elements 107 wound radially about shaft 51 (rather than extend in the armature is subject to the reversing flux as each ing parallel thereto as in the embodiment shown in FIG. pole is passed, and thus low hysteresis losses are experi 1), and rotor 109 has magnets 110 thereon that extend enced. In addition, the effects of flux leakage are re circumferentially around inner cylindrical wall 72 duced so that all of the armature windings experience (rather than extending parallel to shaft 51 as in the em the total flux change and thus are equally useful at pro bodiment shown in FIG. 1).

ducing torque. FIG. 18 illustrates another linear reciprocating imple The device of this invention also has significant heat mentation of the electromagnetic transducer of this transfer advantages. For this reason, the superior high invention in which the structure is flat. As shown, mag power to weight ratio is further enhanced. A thin arma 10 nets 113 are mounted on flat lower return plate 114. ture is made possible by the armature being made up Armature 115 is provided with dispersed conductors entirely of insulated conductors except for the neces 116 and flux carrying elements 117 in the same manner sary volume of the flux carrying members. It is there as described hereinabove with respect to the other em fore possible to provide cooling to both the inner and bodiments illustrated except that the armature is essen outer surfaces of the armature. 5 tially flat rather than cylindrical. An upper return plate By the principles of heat transfer, heat buildup in an 118 is also provided, and armature 115 is movable lin armature, with constant surface temperature and uni early with respect to, and between, lower and upper form internal heating per unit volume, depends on the plates 114 and 118 by means of rollers 120 mounted on square of its thickness. For example, compare an arma the edges of upper plate 118 and rollers 121 mounted in ture 0.25 inches thick (as is possible in this invention) to 20 roller

The mounting boxes 122 (carried by lower plate 114).

basic configuration and geometry of a prototype a solid rotor, fives inches in diameter (as is common in known devices). The heat buildup in such known de transducer constructed according to the principles of vices is some 400 times as great as that of the transducer this invention and based upon computer calculations are of this invention with such an armature. Clearly, the as follows (based upon the use of 24 magnets, conduc electromagnetic transducer of this invention can dissi 25 tors 0.008 inches in diameter, and 144 flux carrying pate more heat than any known conventional trans elements as brought out more fully hereinafter): ducer of similar power rating.

The electromagnetic transducer of this invention can Power (at 10,000 rpm) 40 HP be produced in several topological variations of the Voltage 72 volts dic basic design. In addition to the rotating cylindrical shell 30 Current 425 amps dc configuration, by changing the orientation of the mag Diameter

Armature total thickness 6.5 inches 0.28 inches nets and the windings, the motor can be made to pro Length 3.5 inches duce a linear motion. Other variations (not shown) Weight 15.0 lbs. include pancake and conical configurations. Efficiency (calculated at 10,000 rpm) 97.6% FIG. 17 illustrates a linear reciprocating implementa 35 tion of the electromagnetic transducer of this invention More specifically, the motor calculations as set forth wherein the magnetic flux producing section moves hereinabove are based upon the following motor calcu linearly with respect to the armature in a cylindrical lations:

configuration. To accomplish this end, armature 105 has dispersed conductors 106 and flux carrying elements

Geometric Parameters

L1 is .125 L2 = .02 L3 s 25 La = .02

LS = 3 L6 = .25 L9s 2 R1 = 2.488

M1 = .684 M2 is .513 M3 s .17 M5 = 109 M6 = .054

Material Properties

R9 se .075 U9 is .0000004 DE = .054 RO = 1.724.

BR s 11500 UR is 1.05 HO = S000 MD s.3

Winding Variables

OW is 8.00000E-03 PF - 42 VO = 72 IM = 425 NP = 3

NM as 24 NS - 2 NL = 2 SR = 1 YD - 2

Magnetic Fields

BA = 8000 BMs 10053 HM = 1378 BS = 16000

B - Inner RP s 15181 B - Outer RP = 7136

B - Back at 425 amps = 754 Max current at HD = 2042

P(1) = 7.3 P(2) = 1.2 P(3) = .3 P(4) - 3.7

Weights of the Component Parts

Copper = .72 Epoxy = .30 Magnets = 2.22

Stator iron = 1.11 Return paths = 2.32 Housing = 5.87

Electrical Parameters

No load speed = 11164.7 rpm

Wires/conductor = 56 Effective length = 48

Stat. vols. 7.8 Conductor size is 0.054 by 0.125

Calculated Performance as a Function of Speed

Losses in watts

Page 15

rpm ft-lb amps IR eddy hyst's wind hp eff (%)

wherein

Units of length are inches

Fields are in Gauss B, Oersteds H

Losses are in watts

Forces are lb as are weights

P() = Gauss-in/Oersted, permeances of the flux paths

R = Resistance, ohms and wherein:

Parameter Definition

L1 Inner return path 72 thickness

L6 Outer return path 73 thickness

MI Option, 1 for magnets inside, 2 for out, 3 for both

M3 gap between magnets at pitch line

MS Armature iron pitch

NS Iron pieces (flux carrying elements) 86 per phase and per pole

NC Total # of conductors 84 per phase

SR # of conductors per phase in series

NW if of wires per conductor

PF wire packing factor

Wid density of wire material

DE density of epoxy potting material

NR is no load speed

R Mean armature radius

RO wire resistivity, microohm-cm

KM Hysteresis loss constants

R9 Gas/fluid density, lbm/cubic foot

U9 Viscosity, lbf-sec/square foot

MG Magnet option, 1 for ceramic, 2 for

NdFeB

HC pseudo coercive intensity = BR/UR

BR residual flux density

MD density of magnetic material

UR recoil permeability

H) coercive intensity at the knee

For motor torque verification, the electromagnetic force was measured in an actual test in a linear configu ration similar to that illustrated in FIG. 18, built to test 60 length was 3 X60 = 180 inches. Using these values, the computer simulation of a rotary configuration. A cur force was calculated to be 45 lb. The measured force of rent of 125 amps produced a force of 50 lb. 50 lb compares well with the calculated force of 45 lb The measured magnetic field (using Type 8 ceramic considering the accuracy of the test (for example, the magnets) was 3500 gauss. The active conductor length magnetic field is not absolutely uniform everywhere, spanned three of the four poles and consisted of twenty 65 and fringing field effects were not considered). bars of copper, each 0.150X0.3125 inches in cross sec Measured eddy current, hysteresis and windage tion. Each of the 3X20=60 conductors had an active losses for a transducer constructed according to the length of three inches. Thus the total active conductor principles and description herein are shown in the graph

Page 16

of FIG. 20. This motor delivered 16 horsepower at 7800 generating a magnetic flux mounted on at least one RPM in preliminary testing. of said inner annular wall and said outer wall; and As can be appreciated from the foregoing, the elec an armature, for intercepting said magnetic flux, fixed tromagnetic transducer of this invention is thus able to to said housing, said armature comprising an annu provide an output power to weight ratio that is greater 5 lar member positioned to be disposed one of (i) than one horsepower to one pound in a cooling gas radially adjacent said first annular wall means and medium (using air as the cooling medium), and is be (ii) at least partially within said gap between said lieved to be greater than five horsepower to one pound inner annular wall and said outer wall of said rotor, in at lest some cooling mediums (with a five to one ratio said armature including (i) a plurality of spaced being calculated for the prototype motor as set forth 10 sections of electrical conductors, each section in herein). It should be further appreciated from the fore cluding a plurality of separate conductive wires going that this invention provides an improved electro insulated from each other and (ii) a plurality of magnetic transducer that is lightweight, compact, effi magnetic flux carrying elements interposed be cient and yet capable of delivery high power. tween said sections of electrical conductors, each What is claimed is: 15 flux carrying element comprising a member 1. A brushless, high-speed, high torque electric mo pressed from highly magnetically permeable parti tor, comprising: cles and a binder material for binding said particles a housing: together.

a shaft mounted on said housing to rotate relative 2. The motor of claim 1 further comprising actuation thereto; 20 means for causing rotation of said shaft at a rate of speed a magnetic field-generating rotor secured to said shaft sufficiently high to create a high power density opera to rotate therewith, said rotor having a mounting tion of said motor.

disk connected to said shaft and one of (i) a first 3. The motor of claim 1 wherein said wires have annular wall means having a first magnetic means insulation material thereon, and wherein said flux curry mounted thereon for generating a magnetic flux 25 ing elements comprise highly permeable material and (ii) a second annular wall means comprising an placed over said insulation material on said wires. outer annular wall and an inner annular wall both 4. The motor of claim 1 wherein said housing in supported by said mounting disk and spaced radi cludes means causing air to be passed through said hous ally apart to define an annular gap therebetween, ing adjacent to said armature to dissipate heat and said inner annular wall being spaced radially apart 30 thereby improve operation

of the motor.

from said shaft, and a second magnetic means for