A.proportional band
B.the error signal
C.the reset signal
D.feedback
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A.Dehydrators must be used continuously in a refrigeration system
B.A 25 ton refrigeration system has the same cooling effect as melting 25 tons of ice in 24 hours
C.A thermostatic expansion valve is used to control refrigerated space temperature
D.The liquid receiver functions to collect and remove non- condensable gases
A.Hydraulic
B.Mechanical
C.Pneumatic
D.Electrical
A.Energy can be created or destroyed
B.Energy may not be transformed
C.The total quantity of energy in the universe is always the same
D.None of the above
A.evaporator
B.compressor
C.expansion valve
D.condenser
A.has continuously for a long period
B.suction pressure is below normal
C.oil level is below normal
D.starts after a long idle period
最新試題
A pressure drop through the refrigerant liquid line may cause （）.
When the steering gear is in operation, you should （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）
The output volume of a positive fixed displacement pump can be changed only by （）.
Thermostatic expansion valves can be adjusted for （）.
The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.
If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）