题目内容

For a step-up transformer, the relationship between primary winding N1 and secondary winding N2 is ( ).

A. N2>N1
B. N2=N1
C. N2
D. denpends on its model

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When the AC magnetic contactor is energized, for the flux before and after the moving part is attracted, ( ).

A. F(before)>F(after)
B. F(before)=F(after)
C. F(befoer)

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For the of the phase compound excitation type AVR of a self-excited synchronous generator, the AC side of the rectifier is connected with capacitors delta connected. The function of these capacitor are ( ).

A. resistance-capacitance protection of rectifier
B. compensate the generator terminal voltage change caused by the change of load current
C. compensate the generator terminal voltage change due to load current phase change
D. accelerated voltage built-up process

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三相异步电动机以转速n 正常运转，现突然调换定子的两根进线，电动机最终会反转。在这期间，电动机处于（）状态。

A. 再生制动
B. 能耗制动
C. 反接制动
D. 正常

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自动操舵方式的特点是( )。

A. 船舶不再出现S航迹,直线运行
B. 只能减小S航迹的振幅,但不可能消除
C. 如果系统的灵敏度太高,在大风浪的天气里,舵机投入次数太少,S航迹振幅加大
D. 减轻工作人员的劳动强度,但增加了S航迹的振幅

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For a step-up transformer, the relationship between primary winding N1 and secondary winding N2 is ( ).

A. N2>N1 B. N2=N1 C. N2 D. denpends on its model

When the AC magnetic contactor is energized, for the flux before and after the moving part is attracted, ( ).

For the of the phase compound excitation type AVR of a self-excited synchronous generator, the AC side of the rectifier is connected with capacitors delta connected. The function of these capacitor are ( ).

三相异步电动机以转速n 正常运转，现突然调换定子的两根进线，电动机最终会反转。在这期间，电动机处于（ ）状态。

自动操舵方式的特点是( )。

A. N2>N1
B. N2=N1
C. N2
D. denpends on its model

三相异步电动机以转速n 正常运转，现突然调换定子的两根进线，电动机最终会反转。在这期间，电动机处于（）状态。