However, when {TAIL ~ the number} of {HEAD ~ primary windings} of the main transformer is increased to form two parallel primary windings, for example, two inverter output cables for each round trip, that is, a total of four cables are required 
However , when { TAIL ~ the number } of { HEAD ~ primary windings } of the main transformer is increased to form two parallel primary windings , for example , two inverter output cables for each round trip , that is , a total of four cables are required
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH 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 OTH OTH OTH