A first driving device is provided at {HEAD ~ a radial outer area} of {TAIL ~ the turbine wheel} 
A first driving device is provided at { HEAD ~ a radial outer area } of { TAIL ~ the turbine wheel }
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL