单项选择题
A.removing all but the frictional load during starting
B.relieving intercoolers of high temperature buildups
C.providing high starting torque in the drive motor
D.seating valve plates during compressor shutdown
单项选择题 When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is a （）.
单项选择题 The purpose of the wearing rings used in a centrifugal pump is to （）.
单项选择题 The lowest temperature required to cause self-sustained combustion of a substance independent of any outside source of ignition is called （）.