问答题
简答题
试画出既能使三相异步电动机正、反连续运行，又能在正转或反转时点动的控制电路，要求具有过载、短路、欠压（失压）保护。
【参考答案】
用SB4作正转点动，SB5作反转点动，画出控制电路如图所示。
图中：......
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