That is what you call the OPEN-DELTA CONNECTION... Open Delta Connection:
The open delta transformer connection can be made with only two transformers instead of three . This connection is often used when the amount of three phase power needed is not excessive, such as a small business. It should be noted that the output power of an open delta connection is only 87% of the rated power of the two transformers. For example, assume two transformers, each having a capacity of 25 kVA, are connected in an open delta connection. The total output power of this connection is 43.5 kVA (50 kVA x 0.87 = 43.5 kVA).
Ito ang advantage minsan ng delta connection kasi pwde pa rin makapagoutput ng 3phase kng sakaling masira ang isang trnasformer but w/ less power output.
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