单项选择题
A.a shortage of compressor oil B.warm food in the refrigerator C.excessive condenser cooling water D.a shortage of refrigerant
In the design of hydraulic piping and equipment conside...
单项选择题In the design of hydraulic piping and equipment consideration is given to minimize turbulence in the hydraulic fluid, as this will cause （）.
A.molecular fluid vibration B.energy losses C.wide pressure variations D.mechanical damage to control valves
Which of the conditions listed represents the greatest ...
单项选择题Which of the conditions listed represents the greatest effect of excess frost accumulation on the evaporator coils?（）
A.Keeps the refrigerated space cooler B.Reduces the efficiency of the plant C.Takes the load off the compressor D.Has no affect on the system
When the vessels steering wheel on the navigation bridg...
单项选择题When the vessels steering wheel on the navigation bridge is turned, the difference existing between the position of the wheel and that of the rudder is known as （）.
A.proportional band B.the error signal C.the reset signal D.feedback
