Valves may be operated manually, either by a handle, lever or pedal.

阀门可手动操作，或者通过一个手柄，手柄或踏板。

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That system does use batteries for the controls, but it can also be operated manually.

该系统能够用电池组控制，也能够手动操作。

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With electric actuator, it's can be controlled through valve flow and also can be operated manually when without power.

配合电动执行器可以实现远程阀门流量开度控制，在无电源情况下也可以手动进行操作。

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The pumps, which are working, will be operated manually by EA staff throughout the winter when flooding is possible.

BBC: Kempsey flood defence failure due to waterlogged sensor

Hundreds of thousands of switches and circuit breakers must be operated manually, and the main transmission lines have little instrumentation to monitor the second-by-second flow of electricity from unpredictable new sources like windmills.

FORBES: Juicing the System

Should manually operated vehicles be the ones to give way?

WSJ: Why Driverless Cars Are Inevitable��and a Good Thing