A fail safe system is used in {HEAD ~ a control unit} for opening and closing {TAIL ~ guide vanes} of a pump turbine apparatus operable in both of pump operation mode and turbine operation mode 
for opening
A fail safe system is used in { HEAD ~ a control unit } for opening and closing { TAIL ~ guide vanes } of a pump turbine apparatus operable in both of pump operation mode and turbine operation mode
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH