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