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