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