在标准的4串桥，这些是用来连接的桥梁顶板与底板。

On standard 4 string bridges these are used to attach the bridge top plate to the base plate .

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串级调速系统的主要组成部分是线绕式异步电动机，三相桥式整流器和三相可控硅逆变器。

A cascade speed control system mainly consists of a wound asynchronous motor, a three-phase rectifier and a three-phase thyristor (?) inverter.

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