Engineering Board Exam Reviewer · Three-Phase Systems in Power Applications · hard
The same three equal resistors are connected first in wye and then in delta across the same three-phase line. The total power absorbed in delta compared with wye is
- 3 times as great
- 3 times as great
- the same
- one-third as great
Answer
B. 3 times as great
Solution
In wye each resistor sees VL/ 3, so PY=3(VL/ 3)2/R=VL2/R. In delta each resistor sees VL, so P =3VL2/R. The delta power is 3 times the wye power.
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