Thiết bị & Hệ thốngCâu 287 / 521
NEC 450.9 requires that transformer ventilation openings be arranged so that they:
a.Are always fitted with fans
b.Face downward only
c.Are not blocked by walls or obstructions, allowing required airflow to dissipate heat
d.Are sealed to keep out dust
Giải thích
NEC 450.9 requires ventilation so transformers can dissipate full-load losses without exceeding temperature ratings; openings must not be blocked by walls or obstructions. Forced ventilation is not always required, and sealing openings would defeat cooling.
Trích dẫn luật: 2023 NEC §450.9Luyện miễn phí toàn bộ 521 câu hỏi — không cần đăng ký.
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