轮机英语船舶电气与船舶安全章节练习(2018.03.19)

单项选择题
When an air started, four-stroke/cycle diesel engine is being cranked, the starting air is admitted to each cylinder during what would normally be the（）
A.intake stroke
B.compression stroke
C.power stroke
D.exhaust stroke
单项选择题
Why is it desirable to operate paralleled AC generators at the same power factor?（）
A.Circulating currents are kept to a minimum
B.Field excitation losses are kept to a minimum
C.Generator rotors will have a lesser tendency to hunt
D.Because a power factor increase will decrease kilowatt output
单项选择题
Fuel has to be injected into the engine at a high pressure so that it （） correctly.
A.is purified
B.in timed
C.is compressed
D.atomizes
单项选择题
To reduce the weight of the reciprocating parts, pistons of high-speed engines are made considerably shorterThis results in （）
A.less piston slap and quieter running
B.increased crankshaft bearing wear
C.slightly greater piston wear
D.decreased side pressures
单项选择题
When preparing an engine for water temperature（）
A.should be kept at a proper level by a cooler
B.should be raised to about 80℃ by a heater
C.should be raised gradually
D.should be lowered to about 60℃
单项选择题
A fire is considered "under control" when （）.
A.all hands are at their fire stations
B.all fire-fighting equipment is at the scene
C.the fixed systems are activated
D.the fire is contained and no longer spreading
单项选择题
（）is not installed on the main switchboard.
A.Ammeter and changeover switch
B.Power factor meter
C.Synchroscope
D.Reverse sequence relay
单项选择题
Combustion gases formed in the cylinder of a diesel engine are prevented from blowing past the piston by （）
A.cylinder valves
B.compression rings
C.piston skirts
D.oil rings
单项选择题
The vapors given off by heated fuel oil are flammable, explosive, and （）
A.lighter than air
B.heavier than air
C.odorless
D.nontoxic
单项选择题
The load on the crosshead pin is always （）, so it is the （）half of the bearing which is subject to wear.
A.upwards；top
B.upwards；bottom
C.downwards；top
D.downwards；bottom