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1 某220V直流分激電動機,電樞電阻為0.12Ω,當電樞電流為40A時,轉速為1000 rpm,若不考慮電樞反應,則無載時轉速約為多少?
A 978rpm
B 1022rpm
C 1120rpm
D 1210rpm

E0 = 220V

E1 = V - IARA = 220 - 40 × 0.12 = 215.2V

E1:E0=n1:n0

215.2/220=1000/n0

n0=1022rpm