A.the armature terminals of the motor should be connected in star formation when voltage of power supply is 380
B.the armature terminals of the motor should be connected in star formation when voltage of power supply is 220
C.both A and B are correct
D.the armature terminals of the motor should be connected in reverse ways of A and B
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A.2
B.4
C.6
D.8
A.in such cases, the air supply is no longer optimal, the thermal load will be higher
B.governor hunting will occur
C.torsional vibrations as other mechanical vibrations may occur
D.all of the above are correct
A few spots of turbocharger can be caused by（）
①crash stop of engine
② rapid increased of engine speed
A.①only is correct
B.②only is correct
C.both ① and ②are correct
D.neither ① or ② correct
A.improve power factor
B.reduce voltage oscillation
C.increase the insulation of circuits
D.eliminate regenerated magnetic fields
A.for the release of air from the cooling water
B.providing expansion room for heated cooling water
C.a place for implementing water and water treatment agent
D.all of the above
最新試題
If two A.C.generators are to be operated in parallel, the load is distributed evenly by（）
Diesel engine air start system check valves are opened by （）
The additional mark （）in the Classification Certificate for Machinery means propulsion apparatus is remotely controlled on the navigating bridge control station, and engine assembly control station is unmanned periodically.
Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）
The treatment of the fuel oils involves storage, heating, filtering and（）
The flash point of a residual fuel oil should be used to determine the highest temperature to which oil may be heated（）
Which of the following items don’t belong to dock repair works?（）
A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）
（） is not installed on the main switchboar.
The shipboard oil pollution emergency plan will be invalid after （）