单项选择题
The separate supplies are connected in either star or delta formationThe star formation is most commonly used and requires（） slip-rings on the alternator.
A.two
B.three
C.four
D.five
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相关考题
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单项选择题
After a ship enters service it is（） for the main bus-bar to be made dead.
A.usually
B.commonly
C.exceptional
D.unavoidably -
单项选择题
（） is a machine by which electrical energy is transformed into mechanical energy.
A.An alternator
B.An electric motor
C.A diesel engine
D.A main switchboard -
单项选择题
（） shall be continuously powered and shall have an automatic changeover to a stand by power supply in case of loss of normal power supply.
A.Cooling system
B.Alarm system
C.The air conditioning installation
D.The mooring equipment
