In {HEAD ~ the normal operation} of the pump turbine apparatus in the turbine or pump operation mode, the fail safe valve 47 is held at the illustrated position by {TAIL ~ the force} of a spring associated therewith 
In { HEAD ~ the normal operation } of the pump turbine apparatus in the turbine or pump operation mode , the fail safe valve 47 is held at the illustrated position by { TAIL ~ the force } of a spring associated therewith
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH