【填空题】
低压断路器又称自动空气开关，它除具有开关作用外，还具有（、 ）、（ ）、欠压和漏电保护的作用。
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相关试题
【填空题】
组合开关的主要用途是机床电源的（ ）、用来直接控制小容量电动机的（）。
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熔断器的主要作用是（ ），还可以起到使用电设备与电源（）。
【填空题】
熔断器图形符号是（ ），文字符号是（ ）。
【填空题】
交流接触器的主要结构由（ ）、触头系统 和（ ）组成。
【填空题】
交流接触器的主要作用是（），还具有（ ）和欠压保护 功能.
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交流接触器辅助常开触点的图形符号是（ ），文字符号是（ ）。
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中间继电器的主要作用是（ ），其触点额定电流一般为（ ）。
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中间继电器常开触点的图形符号是（ ），文字符号是（ ）。
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热继电器的主要作用是（ ），其文字符号是（ ）。
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时间继电器按延时方式分，主要有（ ）和（ ）。
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BK、JBK型机床控制变压器常用的输出电压有：6.3V（ ）、（ ）、（ ）、110V。
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控制按钮是一种由人体的（）而进行操作的开关，主要安装在（）。
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一般按钮常开触点的的图形符号是( ), 文字符号是( )。
【填空题】
急停按钮常闭触点的的图形符号是( ), 文字符号是( ).
【填空题】
旋转按钮常开触点的的图形符号是( ), 文字符号是( )。
【填空题】
接近开关常开触点的图形符号是（ ），文字符号是（ ）。
【填空题】
行程开关由（）来控制开合，以控制其运动方向和行程的自动控制电器，主要安装在（）。
【填空题】
行程开关常开触点的的图形符号是（ ）,文字符号是（ ）。
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接近开关的三个电极，一般棕色接（ ）、兰色接负极 、黑色接（ ）。
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感应开关的作用是将（）信号转变为（ ）信号的器件。
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电磁铁是一种将（ ）能转变为（ ）能的电器。
【填空题】
三相交流笼型异步电动机的定子由机座 、（ ）和（ ）三部分组成。
【填空题】
三相交流笼型异步电动机的转子由（ ）、（ ）和转轴 三部分组成。
【填空题】
三相交流笼型异步电动机的接线方式有（ ）和（ ）两种。
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三相交流笼型异步电动机的额定功率是指（ ）, 电动机的输入功率是指（ ） 。
【填空题】
三相交流笼型异步电动机的输入功率（ ）电动机的额定功率，异步电动机的输出功率（ ）电动机的额定功率。
【填空题】
电动机的（ ）转速总是低于电动机的（ ）转速。
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交流电机定子绕组的短路主要有 （ ） 短路、相间短路和 （）短路。
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三相交流笼型异步电动机绕组间绝缘,必须大于（ ）， 三个绕组的直流电阻相差不应超过（ ）。
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电动机直接启动是指加在电动机（）为电动机的（）。
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自锁控制就是：当按下启动按钮时（），按钮松开后（）保持得电，这种接触器通过自身的辅助常开触点使其线圈保持得电的作用称为自锁。
【填空题】
接触器互锁的控制就是：当（）动作时，通过它的（）使另一个接触器不能得电动作，接触器之间这种相互制约的作用叫做接触器互锁。
【填空题】
点动控制主要应用的场合是（ ）、（ ）。
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所谓降压启动，是指启动时（）加在电动机定子绕组上的电压，待电动机启动完成后，再将电压恢复到（）。
【填空题】
定子绕组串电阻的降压启动是指电动机启动时，把电阻串接在电动机()与()之间，通过电阻的分压作用来降低定子绕组上的启动电压。
【填空题】
异步电动机采用 Y- Δ降压起动时，定子绕组先按()联结，后改换成（） 联结运行。
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电动机制动的方法通常有两大类：（）和（）。
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机械制动的含义是利用（）使电动机在（）迅速停转的方法叫做机械制动。
【填空题】
电气制动的含义是使电动机在（）的情况下，产生一个和电动机实际旋转方向相反的（），迫使电动机迅速停转的方法。
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A. Not at all
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___This is Mr Smith speaking now.
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A. I have no time
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A. Certainly
B. Many thanks
C. OK
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A. Who are you?
B. Sorry, he isn't in.
C. Thank you very much.
D. Yes, here you are.
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A. No, I won't
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C. Yes, please
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A. I'm so glad
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A. It went very well.
B. I flew there.
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He ___ driving me home, even though I told him I lived nearby.
A. insisted on
B. insisted at
C. insisted that
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