單項(xiàng)選擇題焊機(jī)的加壓機(jī)構(gòu)應(yīng)保證電極間壓力穩(wěn)定,電極壓力的實(shí)際值與額定值之差不應(yīng)超過額定值的±()

A.8%
B.9%
C.10%
D.11%