{TAIL ~ A motor} drives a brush to sequentially connect the terminals to the slip ring to energize {HEAD ~ the terminals} in sequence 
{ TAIL ~ A motor } drives a brush to sequentially connect the terminals to the slip ring to energize { HEAD ~ the terminals } in sequence
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH