[单选题]
20/5t桥式起重机电动机转子回路测试时,在断电情况下扳动手柄,当转动5个挡位时,要求R5、R4、R3、R2、R1各点依次与()点短接。
A .R6
B .R7
C .R8
D .R9
参考答案与解析: