Magnetic Gear

The objective of studying magnetic gears is to replace mechanical gears which are noisy, require frequent maintenance and lubrication, and suffer from friction losses. The magnetic gear is contactless and quiet in operation, and it requires no lubrication. In addition, it slips when overloaded whereas the mechanical gear may break down when overloaded.
The magnetic gear has been studied more thoroughly in the last decade although there was a patent in 1901 by Armstrong(1) and an improved one in 1941 by Faus(2). Another significant improvement was contributed by Martin in 1968(3) in which steel pole pieces were used. However, it was not commercially marketed because the transmitted torques were small as ceramic magnets were used. Recently, strong rare earth magnets have been developed, and the new operational principle employing the harmonic magnetic flux has also been developed. As a result, a high torque density can be achieved. Hence, high performance magnetic gears can be marketed for industrial and commercial applications.
The theory of mgnetic gearing was established by Dr. Atallah and his colleagues at Sheffield University.

(1) C.G Armstrong: "Power Transmitting Device ", Unites States Patent Office, No. 687, 292, 26th Nov 1901
(2) H.T Faus: "Magnetic Gearing ", Unites States Patent Office, No. 2, 243, 555, 27th May 1941
(3) T. B Martin, JR: "Magnetic Transmission ", Unites States Patent Office, No. 3, 378, 710, 16th April 1968
(4) K. Atallah et al: ''A Novel High Performance Magnetic Gear'', IEEE Transactions on Magnetics, Vol. 37, No. 4, pp. 2844-2846, 2001.

Category:

Science & Technology

Tags:

• magnetic
• gear
• atallah
• sheffield
• university
• magnomatics
• edumation
• mustafa
• daif

[Fol84]

@edumation do you also know the ratio from inner rotor to the pole pieces when the outer rotor ist static, is there a formula like Gr=PL/PH ?

Thx :-)

[edumation]

@Fol84 If pole pieces speed is Ws and Torque Ts and that of inner rotor is Wh and Th then Gr=Ts/Th=Wh/Ws=Ns/Ph.

[edumation]

@Fol84 That's correct! I will upload another video of a gearbox that uses Ps/Ph

[Fol84]

@edumation Ok, thank you very much. What about the pole pieces? Is this normal steel or is it made of lots of steel sheets like in a electrical transformer ?

At magnomatics video it looks like steel bolts in a non-magnetic frame.

[edumation]

@Fol84 Like transformer steel

[edumation]

@Fol84 Like transformer steel

[Fol84]

@edumation This means for your video-example a ratio from inner rotor to pole pieces of => Ns/Ph => 14/4 = 3.5 ?!

Thanks a lot and best regards :-)

[DanFrederiksen]

@edumation just like mesh gears. just with magnetic poles instead of teeth. draw it on paper, you'll see

[edumation]

@DanFrederiksen Magnetic gearing without iron pieces? How?

[DanFrederiksen]

@edumation for same pole numbers it can work as a coupling yes but not gearing.

it is also possible to do gearing without iron but it seems only with point contact like mechanical mesh gears and that would dramatically reduce the torque strength