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单选题
If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be （）.
A
a shortage of compressor oil
B
warm food in the refrigerator
C
excessive condenser cooling water
D
a shortage of refrigerant
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单选题Excessive oil foaming in the crankcase of a refrigeration compressor can result in （）.A
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单选题Short cycling of a refrigeration compressor refers to （）.A
frequently grounding outB
frequently starting and stoppingC
running too fastD
running too slow
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continuous running of the compressorB
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单选题If a refrigeration compressor is running continuously without lowering the temperature in the refrigerated space, the trouble may be （）.A
a shortage of compressor oilB
warm food in the refrigeratorC
excessive condenser cooling waterD
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单选题（）are supplied by main switchboard directly.A
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单选题When a refrigeration compressor is in the ‘off’ cycle, the thermal expansion valve will（）.A
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continue to operate as if the system were in operationC
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单选题Foaming of the oil in a refrigeration compressor crankcase is caused by （）.A
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单选题Excessive oil foaming in the crankcase of a refrigeration compressor at start up can cause（）.A
compressor damage from improper lubricationB
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单选题In the refrigeration compressor the temperature of the vapor is （） by compression.A
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risenC
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考题
单选题It should be ensured that only （） vapor is handled by the refrigeration compressor.A
humidityB
dryC
steamD
oil
考题
单选题The purpose of the refrigeration system low pressure cutout switch is to （）A
protect the compressor from liquid flood backB
protect the compressor from low discharge pressureC
start and stop the compressor upon system demandD
start the compressor after a drop in the evaporator pressure
考题
单选题Under normal conditions, the refrigerant enters the compressor in an operating refrigeration system as a （）.A
liquidB
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单选题Sweating of the refrigeration system compressor crankcase is caused by （）.A
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单选题Excessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur（） when the compressor.A
has continuously for a long periodB
suction pressure is below normalC
oil level is below normalD
starts after a long idle period
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