"Matthias Wirtz" wrote in message
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"michael adams" schrieb im Newsbeitrag
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Assuming the same motor drives both the handrail and the steps, I
would have thought it takes some quite complex engineering to achieve
this feat. Why???

Presumably because the handrail follows a larger radius than the steps,
and thus has a larger circumferance, and so travels a greater distance
for each rotation of the motor.

That sounds logical. But why would the manufacture not use the exact
radius
so that there is no difference in speed between handrail and steps.

Why do they use a slightly lager radius so that the handrail is a tiny
bit faster, never slower than the steps.

....

Simply because the handrail is approximately 2½ feet further away from
the centre, because your hands are 2½ off the ground as compared with
your feet which are actually on the steps.


....

I experienced the same thing at different locations. And now I'm asking my
self if the load on the steps might be the problem. If there are a lot of
people standing on the escalator they might cause a little bit a slippage
in
the transmission between steps and engine while the load on the handrail
keeps pretty much the same.


A better analogy may be two 3 metre diameter drums rotating on pivots
say 10 metres. apart. There's a large belt threaded around the outside
of the two drums, and a another belt threaded around two concentric
2 metre diameter drums attached to the larger drum. This makes the
circumferance of the large drum approx 9.3 metres and that of the smaller
drum approx 6.2 metres

Start off by drawing two vertical marks on the top two belts, say 1 metre
from the left hand drum. Now rotate the left hand drum once clockwise.
The mark on the outside belt - the handrail will have moved 9.3 m to the
right
while that on the inner belt the - steps will have moved only 6.2 m.

I suspect this can all be explained quite clearly in two crisp sentences
by a competent engineer.



michael adams

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--
Matthias Wirtz - Karlsruhe, DE