更多"When the refrigeration demand is sm"的相关试题:
[单项选择]When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.
A. increase the amount of cooling water to the condenser
B. decrease the amount of cooling water to the condenser
C. add more refrigerant to the system
D. remove some refrigerant from the system
[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 adding oil to a refrigeration system, precautions must be taken to ensure that （）.
A. the compressor suction pressure is not too high
B. all air is purged from the pump and charging fittings
C. the high pressure cutout switch is held open to prevent accidental starting
D. the condenser is completely shutdown first
[单项选择]A refrigeration unit will tend to short cycle when operating （）.
A. under heavy loads
B. during hot gas defrost
C. under light loads
D. during starting conditions
[单项选择]When it is necessary to open a refrigeration system for repairs and the system will be open for more than a few minutes, the open ends of the system should be （）.
A. dehydrated
B. purged
C. plugged
D. evacuated
[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]When a sudden increase in steam demand occurs from the boiler, the water level in the drum at the higher pressure will（）
A. rise quickly
B. rise slowly
C. drop quickly
D. drop slowly
[单项选择]When a sudden increase in steam demand comes to normal, the drum pressure will and water level in the drum will（）.
A. rise, rise also
B. rise, drop
C. drop, rise
D. drop, drop also
[单项选择]When there are small differences between the heights of two successive high tides or two successive low tides，the tides are called（）.
A. Diurna
B. Semi-diurnal
C. Solar
D. Mixed
[单项选择]A capsized small sail vessel is best righted when what part of the vessel is downwind?（）
A. Stern
B. Bow
C. Centerboard
D. Mast
[单项选择]When anchoring a small sailing vessel in rough weather，the best anchor line would be composed of（）.
A. chain-wire
B. chain-manila
C. chain-nylon
D. all chain
[单项选择]In small-angle stability，when external forces exist，the buoyant force is assumed to act vertically upwards through the center of buoyancy and through the（）.
A. center of gravity
B. center of flotation
C. metacenter
D. metacentric height
[单项选择]The type of joint formed when a third small plate is riveted over two plates butted together is called a（）.
A. butted joint
B. lap joint
C. strap joint
D. stringer joint
[单项选择]When in operation, it is unavoidable that a small amount of oil （） through leakage, and in order to compensate for these leaks the system is connected to a feed pump.
A. escapes
B. overheats
C. expands
D. accelerates
[单项选择]Your vessel is taking on fuel oil when a small leak develops in the hose and you have ordered the pumping stoppedBefore resuming pumping，you should（）.
A. notify the terminal superintendent
B. place a large drip pan under the leak and ping the scuppers
C. repair the hose with a patch
D. replace the hose
[单项选择]When a vessel navigates in an area with a small underkeel clearance but with adequate space to take avoiding action she（）.
A. should not be regarded as a vessel constrained by her draught
B. should be regarded as a vessel constrained by her draught
C. shall be regarded as a vessel restricted in her ability to maneuver
D. should be regarded as a non-displacement vessel
[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]Insufficient refrigerant in a refrigeration plant may result in （）.
A. high discharge pressure
B. frosting of the crankcase
C. high temperature of the overboard water
D. low suction pressure of compressor
[单项选择]Some refrigeration systems have chemical moisture indicators installed in conjunction with the sight glass in the liquid lineIf excess moisture is present in the system, the indicator will （）
A. activate the driers
B. change color
C. secure the compressor
D. add a predetermined amount of liquid drier
