The positions of the tracers is determined by differential transformers having {HEAD ~ cores} fixed for {TAIL ~ radial movement} with respective tracers 
fixed for
The positions of the tracers is determined by differential transformers having { HEAD ~ cores } fixed for { TAIL ~ radial movement } with respective tracers
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH