The engine can be run at varying speeds causing {TAIL ~ the generator} to give variable frequency AC electrical power output which is converted by the frequency converter means to {HEAD ~ an AC electrical power output} having substantially the predetermined constant frequency of the mains 
The engine can be run at varying speeds causing { TAIL ~ the generator } to give variable frequency AC electrical power output which is converted by the frequency converter means to { HEAD ~ an AC electrical power output } having substantially the predetermined constant frequency of the mains
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH