{HEAD ~ A solution} of the present invention is to divide {TAIL ~ each back iron} into segments such that there is a physical air gap between the back iron segments of two adjacent magnet clusters 
is to divide
{ HEAD ~ A solution } of the present invention is to divide { TAIL ~ each back iron } into segments such that there is a physical air gap between the back iron segments of two adjacent magnet clusters
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH