Electrical perpetual motion machinists usually present a machine that
causes a small battery to generate a huge amount of power. The most common
problem here is that the "huge amount of power" was incorrectly measured.
AC power measurements are tricky; you can't just multiply the voltage and
current, because they may be out of phase. Thus, measuring 10 Volts and
10 Amps could indicate anything from 0 to 100 Watts, depending on the power
factor. In addition, most AC meters expect a sinusoidal wave; if they are
given some other wave they may be totally wrong. A simple argument against
these machines is; "If they can provide so much energy, why do they need
the battery to keep going?"
8.2: Why don't mechanical perpetual motion machines work?
Mechanical perpetual motion machines depend on rising and descending
weights. The problem is that the amount of energy that you get out of a
descending weight is exactly the same amount that it took to raise the
weight in the first place: gravity is said to be a "conservative" force.
So no matter what the weights do, you can't get energy out.
8.3: Why don't magnetic perpetual motion machines work?
Magnetic motors have a clever arrangement of magnets which keeps the
motor rotating forever. Not surprisingly, whenever someone tries to build
one, the motor rotates for a while and then stops -- this is usually attributed
to the magnets "wearing out". These motors usually rely on using magnets
as low-friction bearings, meaning the "motor" can coast for a long time,
but it doesn't supply any power. Magnetism is like gravity; you can store
potential energy and get it back, but you can't get more energy no matter
what you try.
8.4: Magnets can levitate. Where is the energy from?
Levitating magnets do not require energy, any more than something resting
on a table requires energy. Energy is the capacity for doing work. Work
can be measured by force times distance. Although the magnets are exerting
a force the levitated object is stationary, so the magnets aren't supplying
8.5: But its been patented!
So what? Patent offices will not grant a patent on a "perpetual motion
machine" (some just require a working model) but if you call it a "vacuum
energy device" and claim that it gets its energy from some previously unknown
source then you can probably get a patent. Patent offices are there to
judge whether something has been invented before, not whether it will work.
The ban on devices labelled "perpetual motion" is a special case because
the patent officers dislike being cited as some sort of approval by con-men.
8.6: The oil companies are conspiring to suppress my invention!
This is a conspiracy theory. See the entry on these in section 0.
In most of the US the utility companies are required by law to
buy your excess electricity if you produce your own. If you've got an energy
machine, build it in your basement, phase match it to the line, and enjoy.
8.7: My machine gets its free energy from [X].
A number of machines have been proposed which are not "perpetual motion"
machines in the sense of violating the law of conservation of energy. Mostly
these are based on bogus science. One inventor claims that atoms of copper
wire are being converted to energy in accordance with Einstein's "e=mc^2".
However he fails to explain what causes this transformation and how this
energy is converted into electrical energy rather than gamma rays or heat.
8.8: Can gyroscopes neutralise gravity?
Gyroscopes (or gyros) are a favorite of "lift" machine inventors because
many people have come across them and they behave rather oddly. However
there is nothing all that mysterious about the behaviour of gyros. You
can use Newtonian physics to explain them. Briefly, if you imagine a bit
of metal on the edge of a spinning gyro, then to turn the gyro you have
to stop the bit of metal moving in its current direction and start it moving
in another direction. To do this when it is moving fast you have to push
it rather hard. Nothing about this makes the thing get any lighter (in
fact to be pedantic, the gyro gets very slightly heavier when it spins,
in accordance with Einstein's theory of relativity.)
8.9: My prototype gets lighter when I turn it on.
Weighing something which is vibrating on ordinary scales is a sure way
of getting a wrong answer. The vibration from the machine combines with
"stiction" in the scales to give a false reading. As a result the weight
reductions reported for such machines are always close to the limits of
accuracy of the scales used.
8.10: Can magnets improve fuel efficiency or descale pipes?
Both of these questions come around fairly regularly. Some companies sell magnets which clip around pipes. Sometimes they are sold for use in hard water areas, where they are supposed to prevent the buildup of limescale. On other occasions they are sold for cars, where they are supposed to increase fuel efficiency.
Neither of these claims has ever been substantiated by careful testing, and there is no theoretical explanation for the supposed effects. The advertisers try to make it sound like there is, but its actually just pseudo-scientific eyewash.
Note that in some cases installing the fuel magnets according to the instructions will give increased fuel efficiency. This is because the instructions tell you to adjust the carburettor. The result is that the engine runs leaner than it was designed to, causing increased fuel effeciency (based upon mileage), higher production of nitrous oxides (emissions / smog) and a shorter life. The magnet has nothing to do with it.
If this worked then car companies would install it themselves and hence sell more cars.
NOTE from Skeptic X: Well, if people think something produces
more desirable cars then car companies will install or use it. I don't
think that whether a car company uses something or not is necessarily a
good indicator of whether it is beneficial or works. Car companies must
respond to the market.