In recent years, there has been gro

In recent years, there has been growing interest in the use of magnetic gears as replacements for conventional mechanical gears[1−5]. In a number of application sectors, magnetic gears offer advantages over their mechanical counterparts, reduced maintenance requirements, improved reliability, physical isolation between input and output shafts, elimination of gearbox jamming, and inherent overload protection[6]. With the emergence of rare earth permanent magnet materials, the static torque transmission capability of magnetic gears can now compete with traditional mechanical gear counterparts[7,8]. Moreover, previously reported applications with embedded mechanical planetary gears[9,10] can now be replaced with integrated magnetic gear counterparts. For instance, [10] with an integrated magnetic gear resulted in the “pseudo” direct drive of [11]. Magnetic gears and magnetically-geared motors and generators are being considered for many applications, e.g., electric/hybrid vehicles[12−14], marine[15], wind[16−18] and tidal-turbines[19−21].