Services, Grounding & BondingCâu 44 / 120
What is the secondary full-load current of a 75 kVA transformer with a 208Y/120-volt, three-phase secondary?
a.120 amperes
b.361 amperes
c.208 amperes
d.104 amperes
Giải thích
Secondary current is I = VA / (1.732 x E) = 75,000 / (1.732 x 208) = 75,000 / 360.3, or about 208 amperes. The 361-ampere answer divides by the voltage alone, 120 amperes uses the phase voltage incorrectly, and 104 amperes is roughly half the correct value.
Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
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