# Energy of an Engine

I'm a computer science and math major, but am doing a project involving escalators (and their engines). In the project, I am making
the assumtion that there is a function (call it E(s)) that gives the amount of energy that the escalator's engine requires per second to maintain a given speed "s" (from 0 to 1, where 0 is not moving and 1 is full speed). I am pretty sure that this assumption is valid, but here's where my question comes in:
I want to know how much energy it takes to change speeds. Say I want to change from s1 to s2. Right now I am thinking that the energy required to do this is the integral of E(s) from s1 to s2. Is this assumption valid? If not, what IS this amount of energy?
Thanks
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On 3/31/07 4:13 PM, in article snipped-for-privacy@n59g2000hsh.googlegroups.com, " snipped-for-privacy@gmail.com"

You have incomplete understanding of mechanics. E(s) is the energy required to overcome friction and windage at any constant speed. In addition, torque is required to accelerate the mass. That is, you must calculate the energy required to increase the kinetic energy from one speed to the other. This is really independent of E(s) and is equal to the integral of mv^2 of all the moving parts.
Bill -- Fermez le Bush--about two years to go.
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wrote:

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wrote:

Another key point is if one is talking about an escalator for people, the energy needed per unit time depends on the number of people moving up/down on the escalator. The energy of lifting people up 20 feet is probably signifcantly more than the friction losses of a well designed mechanism. And varies with the total weight of those on the machine.
daestrom
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wrote:

Bill, if you want to use French, you should say "Fermez la Bush".

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On 4/3/07 1:52 PM, in article Z7zQh.1994\$F%1.596@trnddc01, "AL BENSER"
There may be many problems with GWB but I do not think being feminine is one of them
Bill. -- Fermez le Bush--about two years to go.
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Ya, I give you a partial point . . . .hahaha
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Energy is function of time, it is =(power X time). Instead of calculating the energy every second, because that energy varies greatly during the escalator operation (actually that elevator gives you back energy when it is going down!!), assuming the control is properly designed . . . .
Therefore, it makes more sense to calculate the total energy consumed for one full cycle, one up and one down travel.