When both the first and second connection changing switches are closed, {HEAD ~ the interconnection} of the stator windings becomes {TAIL ~ a parallel Y connection} in which the phase difference produced is 60° 
becomes
When both the first and second connection changing switches are closed , { HEAD ~ the interconnection } of the stator windings becomes { TAIL ~ a parallel Y connection } in which the phase difference produced is 60 °
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH