download PDF


Disk electromechanical energy converters are widely used in electric vehicles, pumps, centrifuges, hoists and robotics. They are used in low-speed and high-speed applications. The use of disc electromechanical energy converters as generators is justified in wind power plants, microturbines, portable generator sets, drilling rigs, elevator drives and electric vehicles. The power range of disk electromechanical energy converters currently varies from watt to several megawatts.

The article considered analysis of the scientific and technical literature on disk electric machines. A comparative analysis of the characteristics of disk and cylindrical energy converters is made, as a result of which it was revealed that disk machines with an axial magnetic flux are most suitable for use as servomechanisms and generators where their properties have advantages over cylindrical machines. In this case, disk electric machines, unlike electric machines with a cylindrical rotor, have the same axial dimensions for the same weight and size parameters, which makes it possible to integrate them into various elements of existing systems, that is, in some cases, the disk structure has a higher ergonomics.

The basic design schemes of disk machines such as single-sided and double-sided, slotted and unrestricted, with and without magnetic cores, with internal or external rotors, with surface or internal permanent magnets, like single or modular machines, are presented. A description is given of the structural units of disk machines used in various fields, as well as examples of their commercial implementation. The substantiation of the choice of materials, applied disk electric machines is suggested.


Disk type electric machine, axial magnetic flux, permanent magnets, construction overview.

Flur R. Ismagilov

D.Sc. (Eng.), Professor of the Department of Electromechanics, Ufa State Aviation Technical University, Russia.

Viacheslav E. Vavilov

Ph.D. (Eng.), Associate Professor of the Department of Electromechanics, Ufa State Aviation Technical University, Russia.

Ildus F. Sayakhov

Postgraduate Student of the Department of Electromechanics, Ufa State Aviation Technical University, Russia.

1. Campbell P. The magnetic circuit of an axial flux DC electrical machine, IEEE Trans. MAG-11(5): pp. 1541-1543. 1975. 661 p.

2. Chan C.C. Axial-field electrical machines: design and application, IEEE Trans. EC-2(2): pp. 294-300. 1987.

3. Gieras J.F., Wing M. Permanent magnet motor technology: design and applications.2nd ed., Marcel Dekker, New York. 2002.

4. Leung W.S., Chan C.C. A new design approach for axial-field electrical machine, IEEE Trans. PAS-99(4): pp. 1679-1685. 1980.

5. Miti G.K., Renfrew A.C. Field weakening performance of the TORUS motor with rectangular current excitation, Int. Conf. on Electr. MachinesICEM’98, Istanbul, vol. 1, pp. 630-633. 1998.

6. Campbell P. Principle of a PM axial field DC machine, Proceedings of IEE, vol. 121, no. 1, pp. 1489-1494. 1974.

7. Chan C.C. Axial-field electrical machines with yokeless armature core. PhD Thesis, University of Hong Kong. 1982.

8. Amaratunga G.A.J., Acarnley P.P., McLaren P.G. Optimum magnetic circuit configurations for PM aerospace generators, IEEE Trans on AES, Vol. 21(2): pp. 230-255. 1985.

9. Huang S., Luo J., Leonardi F., Lipo T.A. A comparison of power density for axial flux machines based on general purpose sizing equations, IEEE Trans. EC-14(2): pp. 185-192. 1999.

10. Zhang Z., Profumo F., Tonconi A. Axial flux versus radial flux permanent magnet motors, Electromotion, vol. 3, pp. 134-140. 1996.

11. Sitapati K., Krishnan R. Performance comparisons of radial and axial field permanent magnet brushless machines, IEEE Trans. IA-37(5): pp. 1219-1226. 2001.

12. Gieras J.F., Gieras I.A. Performance analysis of a coreless permanent magnet brushless motor, IEEE 37th IAS Meeting, Pittsburgh, PA, U.S.A. 2002.

13. Caricchi F., Crescimbini F., Fedeli E., Noia G. Design and construction of a wheel-directly-coupled axial-flux PM motor prototype for EVs, IEEE-IAS Annual Meeting, IAS-29, part 1, pp. 254-261. 1994.

14. Heller B. and Hamata V. Vysshiye garmoniki v asinkhronnykh mashinakh [Harmonic Field Effect in Induction Machines]. Moscow: Energiya, 1981. 352 p. (In Russian)

15. Chalmers B.J., Hamed S.A., Baines G.D. Parameters and performance of a high-field permanent magnet synchronous motor for variable-frequency operation, Proc. IEE Pt B 132(3): pp. 117-124. 1985.

16. Lukaniszyn M., Wrobel R., Mendrela A., Drzewoski R. Towards optimization of the disc-type brushless d.c. motor by changing the stator core structure, Int. Conf. on Electr. Machines ICEM’2000, vol. 3, Espoo, Finland, pp. 1357-1360. 2000.

17. Lukaniszyn M., Mendrela E., Jagiello M., Wrobel R. Integral parameters of a disc-type motor with axial stator flux, Zesz. Nauk.Polit. Slaskiej, vol. 200, Elecktryka, no. 177, pp. 255-262. 2002.

18. Mendrela E., Lukaniszyn M., Macek-Kaminska K. Electronically commutated d.c. brushless disc motors (in Polish).Warsaw: Gnome. 2002.

19. Caricchi F., Crescimbini F., Fedeli E., Noia G. Design and construction of a wheel-directly-coupled axial-flux PM motor prototype for EVs, IEEE-IAS Annual Meeting, IAS-29, part 1, pp. 254-261. 1994.

20. Evans P.D., Easham J.F. Slot-less alternator with ac-side excitation, Proc. of IEE, vol. 130, no. 6, pp. 399-406. 1983.

21. Hrabovcova V., Brslica V. Disk synchronous machines with permanent magnets – electric and thermal equivalent circuits, Electr. Drives Symp., Capri, Italy, pp. 163-169. 1990.

22. Klug L. Axial field a.c. servomotor, Electr. Drives and Power Electronics Symp. EDPE’90, Kosice, Slovakia, pp. 154-159. 1990.

23. Klug L., Guba R. Disc rotor a.c. servo motor drive, Electr. Drives and Power Electronics Symp. EDPE’92, Kosice, Slovakia, pp. 341-344. 1992.

24. Gair S., Eastham J.F., Profumo F. Permanent magnet brushless d.c. drives for electric vehicles, Int. Aeagean Conf. on Electr. Machines and Power Electronics ACEMP’95, Turkey, pp. 638-643. 1995.

25. Spooner E., Chalmers B., El-Missiry M.M. A compact brushless d.c. machine, Electr. Drives Symp. EDS’90, Capri, Italy, pp. 239-243. 1990.

26. Zhang Z., Profumo F., Tenconi A. Axial flux interior PM synchronous motors for electric vehicle drives, Symp. on Power Electronics, Electr. Drives, Advanced Electr. Motors SPEEDAM’94, Taormina, Italy, pp. 323-328. 1994.

27. Wang R., Kamper M.J. Evaluation of eddy current losses in axial flux permanent magnet (AFPM) machine with an ironless stator, IEEE 37th IAS Meeting, Pittsburgh, PA, U.S.A 2002.

28. Afonin A.A. Disk electric machines with rotating magnetization vectors for permanent magnets. Dop. NAS of Ukraine, 2004, no. 2, pp. 94-101.

29. Afonin A.A., Grebenikov V.V. The structure of electric machines of disk type. Prtsi ІED NASU, 2002, no. 1, pp. 56-70.

30. Ahmed A.B., de Cachan L.E. Comparison of two multidisc configurations of PM synchronous machines using an elementary approach, Int. Conf. on Electr. Machines ICEM’94, vol. 1, Paris, France, pp. 175-180. 1994.

31. Chillet C., Brissonneau P., Yonnet J.P. Development of a water cooled permanent magnet synchronous machine. Int. Conf. on Synchronous Machines SM100, vol 3, Zürich, Switzerland, pp. 1094-1097. 1991.

32. Eastham, J.F., Profumo, F., Tenconi, A., Hill-Cottingham R., Coles, P., Gianolio, G. Novel axial flux machine for aircraft drive: design and modeling, IEEE Trans. MAG-38(5): pp. 3003-3005. 2002.

33. El-Hasan T.S., Luk, P.C.K., Bhinder, F.S., Ebaid M.S. Modular design of high-speed permanent-magnet axial-flux generators. IEEE Trans. MAG-36(5): pp. 3558-3561. 2000.


35. Acarnley P.P., Mecrow B.C., Burdess J.S., Fawcett J.N., Kelly J.G., Dickinson P.G. Design principles for a flywheel energy store for road vehicles, IEEE Trans. IA-32(6): pp. 1402-1408. 1996.

36. Patterson D., Spee R. The design and development of an axial flux permanent magnet brushless d.c. motor for wheel drive in a solar powered vehicle, IEEE Trans. IA-31(5): pp. 1054-1061. 1995.

37. Ramsden V.S., Mecrow B.C., Lovatt H.C. Design of an in wheel motor for a solar-powered electric vehicle, Proc. of EMD’97, pp. 192-197. 1997.

38. Cascio A.M. Modeling, analysis and testing of orthotropic stator structures, Naval Symp. on Electr. Machines, Newport, RI, USA, pp. 91-99. 1997.

39. Coilgun research spawns mighty motors and more. Machine Design 9: pp. 24-25, 1993.

40. Mongeau P. High torque/high power density permanent magnet motors, Naval Symp. on Electr. Machines, Newport, RI, USA, pp. 9-16. 1997.

41. Caricchi F., Crescembini F., Santini E. Basic principle and design criteria of axial-flux PM machines having counter rotating rotors, IEEE Trans. IA-31(5): pp. 1062-1068. 1995.

42. Top drives URL: TopDrives/default.aspx

43. Hakala H. Integration of motor and hoisting machine changes the elevator business, Int. Conf. on Electr. Machines ICEM’2000, Vol 3, Finland, pp. 1242-1245. 2000.

44. Kleen S., Ehrfeld W., Michel F., Nienhaus M., Stolting H.D. Penny-motor: A family of novel ultraflat electromagnetic micromotors, Int. Conf. Actuator’2000, Bremen, Germany, pp. 193-196. 2000.

45. Jang G.H., Chang J.H. Development of an axial-gap spindle motor for computer hard disk drives using PCB winding and dual air gaps, IEEE Trans. MAG-38(5): pp. 3297-3299. 2002.

46. Mavilor's motors are specially suited for high response servo drives. URL:

47. GenSmart, High-efficiency, high power density, variable speed electric motors, generators and drive systems URL:

48. e-TORQ Motors URL:

49. Kessinger R.L. Introduction to SEMA motor technology. Kinetic Art and Technology, Greenville, IN, U.S.A. 2002.

50. Electric machines for propulsion URL:

51. Kessinger R.L., Robinson S. SEMA-based permanent magnet motors for high-torque, high-performance, Naval Symp. on Electr. Machines, U.S.A., pp. 151-155. 1997.

52. Kessinger R.L., Stahura P.A., Receveur P.E., Dockstader K.D. Interlocking segmented coil array. U.S. Patent No. 5, 744, 896. 1998.

53. El-Hasan T., Luk P.C.K. Magnet topology optimization to reduce harmonics in high-speed axial flux generators, IEEE Trans. MAG-39(5): pp. 3340-3342. 2003.

54. Halbach K. Design of permanent multipole magnets with oriented rare-earth cobalt material, Nuclear Instruments and Methods, Vol. 169, pp. 1-10. 1980.

55. Halbach K. Physical and optical properties of rare earth cobalt magnets, Nuclear Instruments and Methods, vol. 187, рр. 109-117. 1981.

56. Halbach K. Application of permanent magnets in accelerators and electron storage rings, J. Appl. Physics, vol. 57, pp. 3605-3608. 1985.

57. Sadeghirad M. Designing a coreless high-speed axial flux PM generator for microturbines // Journal of computer & robotics no. 1, pp. 63-67. 2011.