Water was the main source of mechanical power, and by the end of the seventeenth century, England alone is thought to have had some 20,000 working mills.

水是机械动力的主要来源，而到了17世纪末，人们认为仅英格兰就有2万个左右的工作磨坊。

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That's by design, because you don't want to end up in a situation where a problem at the plant cuts off its own power source.

这是故意的，因为你不希望出现因电站本身的问题导致了它自身电源被切断的情况。

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The controller sends signals to the power source to move the robot arm to a specific position and to actuate the end effectors.

控制器负责发送信号给动力源并驱使机器人手到达准确的位置，激活终端操作机构的运行。

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For added convenience, the SL30 is powered by easily available, AA alkaline batteries, assuring end-users that they can find a replaceable power source no matter where they may be.

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