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1 一直流分激式電動機,額定電壓100 V,額定容量5 kW,電樞電阻為0.08Ω,若欲降低起動電流為滿載電流的2.5倍時,則電樞繞組應串聯多少歐姆的起動電阻器? 96 統測
A 0.09Ω
B 0.18Ω
C 0.36Ω
D 0.72Ω

滿載電流 I = P/V = 5k/100 = 50A

起動電流 IS = 2.5 × 50 = 125A

RA+Rx = 100 / 125 = 0.8A

Rx = 0.8 - 0.08 = 0.72Ω