Among the basic categories of equipment, which of the following are used to convert mechanical into hydraulic energy？
A. the hydraulic pumps
B. valves
C. hydraulic cylinders
D. hydraulic motors
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Which of the problems listed could cause erosion of the expansion valve disks and seats？
A. Overcharging the system with refrigerant
B. Faulty compressor suction valve
C. Failure of the high pressure cutout
D. Flash gas formed in the liquid line
Mooring winch should be equipped with mechanical brakes which are capable of holding ______.
A. half the breaking strength of the mooring line
B. the full breaking strength of the mooring line
C. the maximum expected tension of the mooring line
D. 50% over the working tension of the mooring line
A centrifugal pump may fail to deliver water when first started if the ______.
A. water seal pipe is plugged
B. pump is not primed
C. seal ring is properly located
D. impeller is flooded
The major cause of trouble in a mechanical-hydraulic governor is contamination of the hydraulic fluid by ______.
A. dirt
B. fuel oil
C. governor cooling water
D. fuel oil tar(焦油)
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