In this case, a magnet A having a portion B which does not change the breadth of a magnet in the circumferential direction even if the distance from {HEAD ~ the center} of {TAIL ~ revolution} changes, is arranged 
In this case , a magnet A having a portion B which does not change the breadth of a magnet in the circumferential direction even if the distance from { HEAD ~ the center } of { TAIL ~ revolution } changes , is arranged
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH