A dual-rotor motor is a motor having two rotors within the same motor housing. This rotor arrangement can increase power volume density, efficiency, and reduce cogging torque.[1][2]
Stator on the outside
[edit]In one arrangement, the motor has an ordinary stator. A squirrel-cage rotor connected to the output shaft rotates within the stator at slightly less than the rotating field from the stator. Within the squirrel-cage rotor is a freely rotating permanent magnet rotor, which is locked in with rotating field from the stator. The effect of the inner rotor is to reenforce the field from the stator.[1] Because the stator slips behind the rotating magnetic field inducing a current in the rotor, this type of motor meets the definition of an induction motor. [3][4]
Stator between rotors
[edit]![](https://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Rotor_for_dual_rotor_motor.pdf/page1-220px-Rotor_for_dual_rotor_motor.pdf.jpg)
In another arrangement, one rotor is inside the stator with a second rotor on the outside of the stator.[2] The photo labelled FIG. 8 is from a patent application. It shows two rotors assembled into a single unit, with eight permanent magnets attached to the outer surface of the inner rotor, and eight to the inner surface of the outer rotor.[5]
Vendors are working on both axial[6] and radial flux configurations.[7] In one axial flux design, the rotor is a disk that sits between two symmetric rotor disks.[6]
References
[edit]- ^ a b Diao, Tongshan (2015). "Study on Dual-Rotor Permanent Magnet Induction Motor and Performance". The Open Electrical & Electronic Engineering Journal. 9 (1): 584–590. doi:10.2174/1874129001509010584 (inactive 2024-04-17). ISSN 1874-1290.
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: CS1 maint: DOI inactive as of April 2024 (link) - ^ a b Hwang, Myeong-Hwan; Lee, Hae-Sol; Yang, Se-Hyeon; Lee, Gye-Seong; Han, Jong-Ho; Kim, Dong-Hyun; Kim, Hyeon-Woo; Cha, Hyun-Rok (2019). "Cogging Torque Reduction and Offset of Dual-Rotor Interior Permanent Magnet Motor in Electric Vehicle Traction Platforms". Energies. 12 (9): 1761. doi:10.3390/en12091761. ISSN 1996-1073.
- ^ "IEC 60050 Section 411-31: Rotation Machinery - General". International Electrotechnical Commission. October 1990. Retrieved March 22, 2021.
- ^ induction motor. HarperCollins. 2021. Retrieved April 9, 2021.
- ^ US 6924574B2, "Dual-rotor, radial-flux, toroidally-wound, permanent-magnet machine", assigned to Wisconsin Alumni Research Foundation
- ^ a b "Double-rotor or Double-stator: a Matter of Efficiency". traxial.com. 2021-08-28. Retrieved 2024-03-31.
- ^ Weiss, C.C. (2024-07-20). "Is this radical two-rotor hub motor the secret to cheap 500-mile EVs?". New Atlas. Retrieved 2024-07-24.