So when we rotate the wiper, the position where the wiper contacts the track changes, and thus changes the effective length of the resistive material that electricity flows through.

所以当转刷时， 刷接触轨道的位置会发生变化，从而改变流流经的阻材料的有效长度。

All escalators do have brushes though.

不过， 所有动扶梯都有刷。

How do these brushes make escalators safer?

这些刷如何让动扶梯更安全？

The wiper contacts the track in different locations than before, thus changing the distance along which the electricity passes through the resistive track, thereby changing the overall resistance.

刷与轨道接触的位置与之前不同，从而改变了流通过阻轨道的距离，进而改变了整体阻。

So, escalator brushes were incorporated as a safety standard to either stop something from entering the gap or deflecting it.

，动扶梯刷被纳入安全标准， 以阻止某些东西进入缝隙或使其偏转。

Inside we find the small metal piece we've been talking about and it's called a wiper.

内部找到了之前提到的小金属片，它叫做刷。

We can see that this metal disc, or wiper, is rotated by the following bracket.

可以看到这个金属圆盘，或刷，是由后面的支架转的。

The escalator brushes are actually a safety feature.

动扶梯刷实际上是一项安全功能。

The wiper is specially designed so that the metal is bent to continuously press against the track at an exact set of locations.

刷经过特殊设计，使得金属弯曲并持续在特定位置压紧轨道。

One connects to the wiper, and the other two connect to each side of the track for measuring left and right or up and down motions.

一端连接到刷，另外两端则连接到轨道的两侧，用于测量左右或上下动作。