{TAIL ~ The magnitude} of {HEAD ~ a power component} common to all the power sources or frequency, if the power sources are AC generators driven by constant speed drives, is compared to a reference to provide an error signal 
{ TAIL ~ The magnitude } of { HEAD ~ a power component } common to all the power sources or frequency , if the power sources are AC generators driven by constant speed drives , is compared to a reference to provide an error signal
TAIL TAIL TAIL TAIL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH