On {HEAD ~ the outer peripheral surface} of {TAIL ~ the bobbin main portion} is wound with a primary windings 
On { HEAD ~ the outer peripheral surface } of { TAIL ~ the bobbin main portion } is wound with a primary windings
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH