更多"When a refrigeration compressor has"的相关试题:
[单项选择]When a refrigeration compressor motor fails to start, the FIRST thing that should be checked for is a ().
A. loose expansion valve control bulb
B. low differential setting on the H-Pcutout
C. blown fuse in the motor circuit
D. faulty suction pressure regulator
[单项选择]When a refrigeration compressor is in the ‘off’ cycle, the thermal expansion valve will().
A. always be wide open when the compressor restarts
B. continue to operate as if the system were in operation
C. remain open until evaporator pressure equalizes, then close until the compressor restarts
D. always be completely closed until the compressor restarts
[单项选择]Badly leaking refrigeration compressor discharge valves will cause().
A. overfeeding of the expansion valve
B. damage to the condenser
C. constant running of the compressor
D. flooding of the receiver
[单项选择]Short cycling of a refrigeration compressor refers to ().
A. frequently grounding out
B. frequently starting and stopping
C. running too fast
D. running too slow
[单项选择]If the refrigeration compressor crankcase is sweating, the cause may be due to ().
A. a shortage of refrigerant
B. the compressor running continuously
C. liquid refrigerant returning to the compressor
D. the compressor short cycling on the high pressure cutout
[单项选择]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
[单项选择]In the refrigeration compressor the temperature of the vapor is () by compression.
A. raised
B. risen
C. reduced
D. maintained constant
[单项选择]The refrigeration compressor in a water cooled refrigeration system is short cycling on the high pressure cutout switch, One reason for this could be the ().
A. system is low on refrigerant
B. high pressure cutout switch is improperly adjusted
C. discharge valves are leaking slightly
D. discharge valves are leaking excessively
[单项选择]Noise in a refrigeration compressor can be caused by ().
A. worn bearings and piston pins
B. slugging due to flooding back
C. too much oil in circulation
D. All of the above
[单项选择]If a refrigeration compressor is short cycling on high head pressure, you should ().
A. purge the condenser if the waterside is dirty
B. check for proper water flow through the condenser
C. increase the high pressure cutout setting
D. reduce the cooling water flow
[单项选择]If a refrigeration compressor were short cycling on the low pressure cutout switch, the probable cause for this might be the ().
A. system was overcharged with refrigerant
B. high pressure switch was improperly adjusted
C. expansion valve strainers were fouled
D. suction valves were leaking slightly
[单项选择]If the capacity of the refrigeration compressor is too small, the excess vapor will accumulate in the evaporator, causing the pressure to ().
A. rise
B. fall
C. be maintained constant
D. None of the above is true
[单项选择]If a refrigeration compressor will not start, the reason may be ().
A. the pressure regulating valve is not closing
B. an excessive lack of refrigerant in the system
C. badly leaking discharge valves
D. worn piston rings
[单项选择]Foaming of the oil in a refrigeration compressor crankcase is caused by ().
A. refrigerant boiling out of solution from the lube oil
B. liquid refrigerant flooding the compressor and system
C. lube oil viscosity being reduced by refrigerant dilution
D. compressor suction pressure suddenly increasing
[单项选择]In the () refrigeration compressor one end of the crank shaft extends through the crankcase house for connection, via a coupling or pulley, to an external drive motor.
A. open-type
B. hermetic
C. semi-hermetic
D. all the above
[单项选择]Refrigeration system compressor crankcase sweating is an indication of ().
A. insufficient lube oil circulating through the system
B. excessive circulation of lube oil through the system
C. insufficient refrigerant in the system
D. an overworked compressor
[单项选择]A refrigeration system compressor crankcase is sweating or unusually coldThis is an indication of().
A. a shortage of refrigerant in the system
B. air in the system
C. an accumulation of liquid refrigerant in the crankcase
D. a shortage of oil in the crankcase