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R&DcentA; KOYO SEMO CO, L m . No24-1, Kokubu, Higanjwh, Ibbimi, Osaka 5824023, J q m Ala~lwd -As the demand for elechic power has been incrrssiOg -, the introdwction of a Qwhd energy -age system 0 using a supemnducting magnetic bearing ( S m is needed to level daily bad as much as passible (daily load-leveling). We have studied rotation loss c m of SMB6 with high 'k supenmductors (YBCO) & permaneat magnets (PM) for supporting a nywheel in FESS We have designedandmanufhctuda~machineformeasuringmtalion laps characte-of SMBa The rotor is suspendd by two sets of ladial active magnetic bearings (1RaAMBs), a set of axial adive magnetic bear@ (AxAMB) and a set of SMR Then, we obtained dation loss cbal.rtcteristirs of the mtor levitated by RaAMEk, AxAMB and SMB on tbi3tegtingmachheIn order to allow the realization of a FESS, we recently performed some f m h n d a l studiesto clarify technical issues of a FESS. For example, a ptotype of 0.5kWh class FESS [l] was built. In such FESS, a sqemndudng magnetic bearing (SMB)7 its roGrtian loss ideally zero, being composed of high-Tc zupem-and permanent magnets, is used-So, it is necessary to clarify characteristics of SMB (spring constan& damping ca&icient, rotation loss).By the way, two kinds of structuresof SMB (AXSMB 8L R a S m ; sqem-Iwh a wostww and permanent magnetso.)SMB is mmposed of following three elements, YBCO weie suggested and it was reportedthat a spring umstantof AXSMB & RaSMB is practical but adamping d c i e n t is not sullicient [2]. In order to assist the damping fimdion of SMB, it is necesssnyto add adamping fkction of other devices (ex. M). On the other hand, there are some lhatum [3][4][5l that reported about the rotaton loss of SMB. ?hese literadures have reported w l y low loss of SMB, but under a special experimental condition. Inthis paper, we repoa rotadion loss c-. 'cs of RasMB (as well SMB) measured uder various load conditions. There are one SMB stator with sc and two SMB mtors with difxmt PMS having different magnib& of irregularity of magnetic density in M & d i r e c t i o n . We designed and man-a testing machine for a of rotaton loss c -'cs of SMBs. A cross section view of the apparatus is s h o w in Fig.1. ?his apparatus, composed of following parts, is in a vacuum chamk. A)a main shaft with PM attached at lower part, B)an inducton motor mounted at middle paa of a main shaft, c>two sets of radial active magnetic -s) mounted above and UIhder an induction motor, D)a set of axial active magnetic bearin&AxAIVlB) mounted at the upper part of the main shaft, E)SC(YBCO) & C/S(SUS304) mounted at lower part of main shaft. The SC and US are able to be moved in axial direction by a z-stage with aload-cell unit driven by a stepping motor: B. Pdornumce ofSMB SC contained in US was assembled firm eight pieces of bulk yBco(see in Fig.2). On the other hand, PM has thm layers magnetized in m w directon( ?, . 1 ;see in Fig.3). 'Ihe gap between SCandPMinradialdirectionis 1.4mmincludingaseal-plateofC/S. We tested the SMBs using two kinds of PM (Pr type:WMPr and...

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Active magnetic bearings (AMBs) are applied to turbomolecular pumps (TMPs) and milling spindles. However, their application areas are limited because they are costlier and require larger space than conventional mechanical bearings. Omitting position sensors from AMBs is one of the promising methods to solve such problems. An additional merit is that rotors can be shortened to have a higher critical speed by removing sensor targets from the rotor. The sensorless operation of AMBs has already been achieved in several instruments developed for experimental study. In this research, the sensorless magnetic suspension method is applied to a TMP manufactured as an industrial product, and it is demonstrated that sensorless AMBs can suspend a high‐speed rotor.