Motors & EquipmentCâu 93 / 120
A continuous-duty motor over 1 horsepower is marked with a temperature rise of 40 degrees C but no service factor. What percentage of nameplate full-load current sets the maximum overload device?
a.140 percent
b.115 percent
c.125 percent
d.250 percent
Giải thích
Motors with a marked temperature rise not over 40 degrees C, like those with a service factor of 1.15 or greater, are permitted overload protection at 125 percent of nameplate current. The 115 percent figure applies to all other motors, 140 percent is the allowance when the initial setting will not carry the load, and 250 percent is a short-circuit protection value.
Trích dẫn luật: 2023 NEC §430.32(A)(1)Luyện miễn phí toàn bộ 120 câu hỏi — không cần đăng ký.
Câu hỏi liên quan cùng chủ đề
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