{TAIL ~ a plurality} of relays adapted for controlling power levels by {HEAD ~ means} of controlling level combinations of said contactors, said relays operated by means of logic gates operating upon desired and actual power levels 
{ TAIL ~ a plurality } of relays adapted for controlling power levels by { HEAD ~ means } of controlling level combinations of said contactors , said relays operated by means of logic gates operating upon desired and actual power levels
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH 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