Motors & EquipmentCâu 94 / 120
A continuous-duty motor over 1 horsepower has no marked service factor and no marked temperature rise. What is the maximum overload device rating as a percentage of nameplate full-load current?
a.140 percent
b.125 percent
c.115 percent
d.175 percent
Giải thích
Motors that carry neither a service factor of 1.15 or greater nor a marked temperature rise of 40 degrees C or less are limited to 115 percent of nameplate current, because there is less thermal margin available. The 125 percent value applies to the better-rated motors, 140 percent is the permitted increase when the motor will not start, and 175 percent is a fuse sizing percentage.
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
- For that same two-motor feeder, if the largest branch-circuit protective device is 90 amperes, what is the maximum feeder overcurrent device rating?
- When sizing motor branch-circuit conductors and short-circuit protection, which current value must be used?
- 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?
- Where must a motor disconnecting means be located relative to the motor?
- An air conditioning condensing unit nameplate reads minimum circuit ampacity 24.6 and maximum overcurrent protective device 40. What overcurrent device must be installed?
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