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What power source actuates a solenoid valve ________．
A.Air pressure
B.Hydraulic pressure
C.Electric current
D.Mechanical force
参考答案
更多 “ What power source actuates a solenoid valve ________．A.Air pressureB.Hydraulic pressureC.Electric currentD.Mechanical force ” 相关考题
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Cathodic protection involves supplying electrons to the metal to be protected from an external source. The external source maybe be an external _______ or by__________.
A、dc power sourceB、Alternating Power SourceC、A Galvanic CoupleD、Cathode
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The temperature of the refrigerant in the evaporator coil depends mostly upon the ___.A.refrigerant pressure in the evaporatorB.cooling water temperature to the condenserC.heat load in the refrigerator compartmentD.solenoid valve in the liquid line
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The refrigeration system low pressure cutout switch is actuated by______.A.an electric system managerB.a sensing bulb at the tail coil of the evaporatorC.pressure changes in the suction lineD.failure of the king solenoid valve
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材料：At 1800，the hydraulic steering system failed once again．The master realized he would require shore assistance to rectify the problem，and diverted towards Portland using the thruster to steer by．The weather at this time was south-south-west force 5．At about three hours later，the thruster drive unit failed due to a leaking fuel injector pipe on the power unit．This was replaced using the spare carried on board．Immediately following the engine restart，an adjacent fuel line failed causing shut down of the unit．With no fuel line spares available，the thruster power unit could not be used．The failure of this unit，and that of the main hydraulic steering system，left the vessel without any steering capability．At 2155，with the weather deteriorating and no steering，the master contacted the Portland Coastguard and a“Pan pan”message was broadcast．A tow to Portland Harbor was arranged and she arrived alongside at 0240 the following morning．The subsequent investigation found that the main hydraulic steering system failure was due to a seized shuttle valve in the main hydraulic solenoid valve block．The solenoid valve had been recently overhauled．It was thought that the“O”rings fitted to the shuttle valve were of either the wrong type or a defective one．The valve had seized in such a position that hydraulic pressure by-passed the system preventing use of the hand steering．问题：The vessel was steered by thruster because ________ failed．A.the hydraulic steering systemB.the solenoid valveC.the thruster driving unitD.the hand steeringThe time that the thruster drive unit failed was ________ hrs．A.1800B.2100C.2155D.0240When the hydraulic steering system failed，________．A.the hand steering system could still be usedB.the auto steering system could still be usedC.both hand and auto steering system were out of useD.neither and steering system nor auto steering system was out of useThe real reason that caused the hydraulic steering system to fail was that ________．A.no fuel line spare were availableB.the weather was deterioratingC.the“O”rings fitted to the shuttle valve were of either the wrong type or a defective oneD.the thruster power unit failed请帮忙给出每个问题的正确答案和分析，谢谢！
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What is the reason for the comeback of once controversial power source？( ) A.Water is a local resource.
B.Nuclear can be stored efficiently.
C.Coal can be found everywhere in the world.
D.They cannot be affected by geopolitical turmoil.
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Which of the following tools is BEST used to measure voltage and amperage from a power source?（）A、Loopback PlugB、MultimeterC、Power Supply TesterD、Extension Magnet
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丙烷机控制时间限设定值菜单（）功能是不允许加/减载电磁阀得电加载的时间长度。A、CAPACITY INCREASE SOLENOID OFF TIMERB、CAPACITY DECREASE SOLENOID ON TIMERC、CAPACITY DECREASE SOLENOID OFF TIMERD、SLIDE VALVE RETURN AT SHUTDOWN TIMER
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丙烷机控制时间限设定值菜单（）功能是在自动加/减载模式下，如果需要降低丙烷机的负载，加/减载电磁阀将会在定时器的时间长度内对丙烷机进行减载。A、CAPACITY INCREASE SOLENOID OFF TIMERB、CAPACITY DECREASE SOLENOID ON TIMERC、CAPACITY DECREASE SOLENOID OFF TIMERD、SLIDE VALVE RETURN AT SHUTDOWN TIMER
考题
单选题The refrigeration system low pressure cutout switch is actuated by （）.A
an electric system managerB
a sensing bulb at the tail coil of the evaporatorC
pressure changes in the suction lineD
failure of the king solenoid valve
考题
单选题What is the function of thermostatic expansion valve in a compression refrigeration system?（）A
nonexistentB
for controlling pressureC
for controlling superheatD
for controlling the solenoid valve
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单选题Which of the listed items should be secured before performing any maintenance on a solenoid operated air start valve?（）A
Electric power and starting airB
Lube oil standby pump and control airC
Hydraulic switch and engage jacking gearD
Motor drain and pneumatic control system power
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单选题When measuring AC current flow, you must always connect the meter （）A
in series with the power source and loadB
in parallel with the power source and loadC
insuring correct polarityD
using the lowest range possible to prevent instrument damage
考题
单选题Distilled water from an evaporator may be discharged into a potable water tank （）.A
through a detachable hose connectionB
after passing through an activated charcoal filterC
after chemical analysis shows it is fit for consumptionD
through a solenoid operated three-way valve
考题
单选题What separate the high pressure side from the low pressure side in a refrigeration system?（）A
Condenser and thermal expansion valveB
King and solenoid valvesC
Compressor and thermal expansion valveD
Condenser and solenoid valve
考题
单选题The thermal expansion valve reacts directly to the （）A
temperature in the space being cooledB
liquid refrigerant pressure at the solenoid valveC
pressure drop across the evaporator coilsD
refrigerant gas superheat at the coil outlet
考题
单选题A solenoid valve used in a refrigeration system should be installed （）.A
with the axis of the solenoid horizontal, sensing temperature of the box, and upstream of the thermal expansion valveB
upright, sensing temperature of the box, and upstream of the thermal expansion valveC
upright, sensing temperature of the box, and downstream of the thermal expansion valveD
upright, sensing heat of the tail coil, and upstream of the thermal expansion valve
考题
单选题The principal purpose of sub-cooling liquid refrigerant prior to its entering the expansion valve is to （）.A
increase the refrigerating effect, by decreasing the amount of flash gasB
allow the refrigerant to enter the throttling device in a saturated conditionC
increase the refrigerating effect by increasing the amount of flash gasD
minimize the temperature drop of the liquid as it passes through the solenoid valve to the outlet side
考题
单选题In a refrigeration system, if the cooling water to the condenser fails, the（）.A
box temperature solenoid valve will closeB
expansion valve will closeC
compressor will shutdownD
king valve will open
考题
单选题In a refrigeration system, which of the following statements describes the actions occurring when a solenoid valves, used in conjunction with an unloader head is energized?（）A
The solenoid valves directs high pressure gas to the valve lifting device raising the suction valve off its seat and causing one specific cylinder to become unloadedB
The solenoid valves directs high pressure gas to the underside of the unloading piston, causing it to rise and allowing the recirculating ports to be openedC
When the solenoid valve becomes energized, the valve ports become closed, allowing discharge pressure to build up above the piston, shifting it and causing it to unloadD
The solenoid valve allows the refrigerant to pass from the suction chamber to the top of the unloader piston, causing the piston to lift and unload the cylinder
考题
单选题Which of the listed components is considered to separate the high pressure side of a refrigeration cycle from the low pressure side of the cycle?（）A
The condenser and the expansion valveB
The king valve and the solenoid valveC
The compressor and the expansion valveD
The condenser and the solenoid valve
考题
单选题The solenoid valve can be typed as a（）A
thermal valveB
magnetic stop valveC
bellows valveD
bimetallic valve
考题
单选题A pressure drop in the liquid line of a refrigeration system may cause（）A
the solenoid valve to seizeB
the compressor to huntC
flash gas to form in the liquid lineD
the expansion valve to freeze open
考题
单选题One function of the thermal expansion valve is to（）A
act as a pilot from the solenoid valveB
regulate the amount of refrigerant flow to the coilC
regulate the water flowD
turn the compressor off and on
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