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