control means for controlling {HEAD ~ the speed} of {TAIL ~ the electric motor} to thereby control the rotating speed of the tubular member 
of
control means for controlling { HEAD ~ the speed } of { TAIL ~ the electric motor } to thereby control the rotating speed of the tubular member
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH