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