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
An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably be caused by （）.
Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.
The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.
An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.
A salinity indicator is used to determine the （）.
The general purpose of a heat exchanger is to （）.
Thermostatic expansion valves can be adjusted for （）.
An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.
Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.
A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.