网友您好， 请在下方输入框内输入要搜索的题目：
题目内容
（请给出正确答案）
单选题
Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation （）
A
is good for long term preserving since most insulation is organic and contains some amount
B
lowers the insulation value and is a common cause of fault grounds in idle machines
C
will enhance insulation resistance only if it is fresh water and contains no salt
D
reduces the amount of current supplied or drawn by the machine so horsepower is limited
参考答案
参考解析
解析：
暂无解析
更多 “单选题Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation （）A is good for long term preserving since most insulation is organic and contains some amountB lowers the insulation value and is a common cause of fault grounds in idle machinesC will enhance insulation resistance only if it is fresh water and contains no saltD reduces the amount of current supplied or drawn by the machine so horsepower is limited” 相关考题
考题
Copper losses are _____ losses in the primary and secondary windings of the transformer core.
A、inductiveB、capacitiveC、resistiveD、reactive
考题
Moisture absorbed in the winding or condensed on the surface of electrical machinery nsulation
A.is good for long term preserving since most insulation is organic and contains some amountB.lowers the insulation value and is a common cause of fault grounds in idle machinesC.will enhance insulation resistance only if it is no saltD.reduces the amount of current supplied or drawn by the machine so horsepower is limited
考题
A hygroscopic cargo is defined as a cargo ______．A.capable of absorbing moisture in the form of a gasB.capable of giving off moisture in the form of a liquidC.that is shipped in a liquid stateD.that will ignite in contact with water
考题
The moisture equilibrium chart can be used to determine the ______．A.Absolute moisture content of the air surrounding a hygroscopic cargo when moisture equilibrium existsB.Dew point temperature that the air surrounding a hygroscopic commodity will have when in moisture equilibrium with that commodityC.Enthalpy of the air surrounding a hydroscopic cargo which is in moisture equilibrium with the cargoD.Temperature at which moisture equilibrium will occur in a cargo hold containing a hygroscopic cargo
考题
共用题干
Obtaining Drinking Water from Air HumidityNot a plant to be seen,the desert ground is too dry.But the air contains water,and research scientistshave found a. __________(51)of obtaining drinking water from air humidity."The process we have developed is based exclusively on renewable energy sources_________(52)thermal solar collectors andphotovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的） brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has__________ (58).Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59) atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower surface again to absorb moisture from the air."The concept is suitable for various water________(62).Single一person units and plantssupplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______(63)system components一air moisture absorption and vacuum evaporation一and the research scientistshave already __________(64)their interplay on a laboratory scale.In a further ________(65)the re- searchers intend to develop a demonstration facility._________(58)A:attractedB:affectedC:allowedD:absorbed
考题
单选题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 driersB
change colorC
secure the compressorD
add a predetermined amount of liquid drier
考题
单选题If the moisture content of the cargo sample is（）the Transportable Moisture Limit,then the cargo should be safe to load.A
aboveB
belowC
equal toD
uncertain
考题
单选题The main purpose of an electric space heater installed in a large AC generator is to （）A
prevent the windings from becoming brittleB
prevent moisture from condensing in the windings during shutdownC
prevent acidic pitting of the slip ringsD
keep the lube oil warm for quick starting
考题
单选题A fire, occurring in the windings, of an overloaded electrical motor, is considered a （）.A
class A fireB
class B fireC
class C fireD
class D fire
考题
单选题There is a danger of the starting current that the windings are burnt out（）A
to increaseB
to be so increasedC
increasedD
being so increased
考题
单选题As the air passes through the charge air cooler, its temperature may be reduced and moisture condensed, with the condensate in danger of being carried into the engineSo a water separator should be mounted beneath the bottom part of the engine inlet manifoldA water separator is used in order to （）.A
keep the air from being carried into the engineB
keep the moisture from being condensedC
keep the danger from being carded into the engineD
take away the condensate from the air
考题
单选题Clouds form（）.A
as a mass of warm，humid air rises into the atmosphere and cools，condensing moisture into small dropletsB
as winds blow across bodies of water，the sun causes the moisture to be absorbed and move upward forming cloudsC
dry air compresses moisture from the atmosphere into cloudsD
when the relative humidity of the atmosphere is low
考题
单选题The function of damper windings in a synchronous motor is to （）.A
eliminate slippageB
provide excitationC
provide starting torqueD
increase efficiency
考题
单选题The moisture equilibrium chart can be used to determine the（）.A
Absolute moisture content of the air surrounding a hygroscopic cargo when moisture equilibrium existsB
Dew point temperature that the air surrounding a hygroscopic commodity will have when in moisture equilibrium with that commodityC
Enthalpy of the air surrounding a hydroscopic cargo which is in moisture equilibrium with the cargoD
Temperature at which moisture equilibrium will occur in a cargo hold containing a hygroscopic cargo
考题
单选题The ratio of the weight of moisture contained in a given volume of air, to the weight of moisture that the same sample would hold if saturated, is called the（）.A
absolute humidityB
relative humidityC
specific humidityD
total humidity
考题
单选题The amount of moisture in a given sample of air, when compared with the amount of moisture the air could hold if totally saturated at the existing temperature of the sample, is called （）.A
absolute humidityB
specific humidityC
effective humidityD
relative humidity
考题
单选题Which of the following components are used to convert alternating current produced in the generator windings to direct current?（）A
Armature and equalizerB
Commutator and brushesC
Rotor and interpolesD
Field and exciter
考题
单选题The greatest detrimental effect on idle electrical equipment, such as cargo pump motors, is the（）.A
loss of residual magnetismB
absorption of moisture in the insulationC
insulation varnish flakingD
dirt collecting on the windings
考题
单选题DC generators are classified according to the manner in which（）A
they are usedB
the field windings are connected to the loadC
the armature circuit is connected to the loadD
the field windings are connected to the armature circuit
考题
单选题Hot air can hold（）.A
less moisture than cold airB
more moisture than cold airC
the same amount of moisture as cold airD
moisture independent of air temperature
考题
单选题The presence of bubbles in a refrigeration system liquid line may （）.A
promote refrigerant dehydrationB
be absorbed in the receiverC
cause low condensing pressureD
carry moisture and lead to corrosion
考题
单选题Which of the following statements is correct relative to distillation plant operation?（）A
Distillation is the process of boiling seawater to produce vapor which is condensed into fresh waterB
Evaporation is the second part of the distillation process where brine is removedC
Brine is the result of condensed sea water vaporD
Distillate is the product resulting from the evaporation of fresh water vapor
热门标签
最新试卷