Re: permanent magnet motor

The Ghost In The Machine wrote:
In sci.physics, Sam Wormley
<swormley1@xxxxxxxxx>
wrote
on Sun, 18 Feb 2007 03:28:35 GMT
<DJPBh.1308$PD2.1188@attbi_s22>:
gdewilde@xxxxxxxxx wrote:

If you think it can[']t work, then you are kindly requested to explain
why.


There is a reason perpetual motion machines can't work. Learn
thermodynamics...


Pedant Point:

Erm...no. That's not the reason PPMs don't work.
Thermo is a model of the Universe.

It's a darned *good* model, to be sure...but it doesn't
explain why PPMs can't work. As phrased, he asked why
we think it can't work; thermodynamics is in that case a
perfectly good answer. But one could also say "we think
satellites can't work because the Earth is flat".

Fortunately, we know the Earth is an oblate spheroid
(and satellites have helped determine its oblateness).
We also have quite a bit of evidence that the theory of
thermodynamics works.

But it doesn't really explain why.


"Perpetual motion machines violate one or both of the following two
laws of physics: the first law of thermodynamics and the second law
of thermodynamics. The first law of thermodynamics is essentially a
statement of conservation of energy".

"The second law has several statements, the most intuitive of which
is that heat flows spontaneously from hotter to colder places; the
most well known is that entropy tends to increase, or at the least
stays the same; another statement is that no heat engine (an engine
which produces work while moving heat between two places) can be more
efficient than a Carnot heat engine. As a special case of this, any
machine operating in a closed cycle cannot only transform thermal
energy to work in a region of constant temperature".

.

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