电阻制动时发电机与电动机状态的电枢电流方向(),电阻制动工况主级绕组电流与牵引工况()。
A、一致,相反
B、一致,一致
C、相反,相反
D、相反,一致
参考答案:A
电阻R1=5Ω,R2=15Ω,将两电阻串联后接在电压为6V的电源两端,求:(1)串联后总电阻是多大?(2)电路中的电流是多少?
U.S. President announced permission for oil drilling off the shorelines, ________ the country's effort to reduce energy import from foreign countries.
A.marked
B.marking
C.having marked
D.being marked