Delta-star Connection.—In this method the primaries are connected in delta grouping and the secondaries in star grouping, as in fig. 1,994.
Star-delta Connection.—This consists in connecting the primaries in star grouping, and the secondaries in delta grouping, as in fig. 1,995.
Fig. 1,996.—Two phase transformer connections. Two single phase transformers are used and connections made just as though each phase were an ordinary single phase system.
Ques. What advantage has the star connection over the delta connection?
Ans. Each star transformer is wound for only 58% of the line voltage. In high voltage transmission, this admits of much smaller transformers being built for high pressure than possible with the delta connection.
Ques. What advantages are obtained with the delta connection?
Ans. When three transformers are delta connected, one may be removed without interrupting the performance of the circuit, the two remaining transformers in a manner acting in series to carry the load of the missing transformer.
