In a refrigeration system, if the cooling water to the condenser fails, the().
A. box temperature solenoid valve will close
B. expansion valve will close
C. compressor will shutdown
D. king valve will ope
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铝及其合金焊接时,氧化铝膜极易引起焊缝产生未熔合夹渣、()等缺陷。
胶盖刀开关只能用来控制()以下的三相电动机。
A. 7.5KW
B. 5.5KW
C. 3KW
D. 2KW