Perpetual Motion Machines

ME 3322

Justin Scruggs

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Definitions

• Perpetual Motion– Movement that goes on

forever

• Perpetual Motion Machine– Any closed system that

produces more energy than it consumes

Robert Fludd's “Water Screw“1618

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Classifications

• Perpetual Motion of the First Kind– Refers to machines whose efficiency is > 100%– Produces energy from nothing (“free energy”)– Violates First Law of Thermodynamics

∆E = Q - W-

* (∆E)cycl = 0

+

η = Wcycl

Qin

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Classifications

• Perpetual Motion of the Second Kind– Refers to machines which extract thermal energy

from a single source and convert it into mechanical work

– Violates Second Law of Thermodynamics

Wcycl

< 0: Internal irreversibilities

= 0: No internal irreversibilities

Qcycl = Wcycl

- σcycle

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Classifications

• Perpetual Motion of the Third Kind– Refers to machines in which all mechanisms by

which energy is dissipated is eliminated (i.e. friction, air resistance, etc.)

– Can be approximated but never achieved due to irreversibilities

– In theory, if achieved, the machine is still limited by the First Law of Thermodynamics

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The Overbalanced Wheel

• Idea– Initially thought longer

lever arm on right would turn wheel

• Results– Larger # of weights on

left side balanced out the torque

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The Float Belt

• Idea– Initially thought that

floaters would rise through liquid and turn belt

• Results– Pushing floaters into

liquid at bottom required more energy

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The Capillary Bowl

• Idea– The capillary action

would keep the water flowing in the tube

• Results– Force from mass of

water was larger than the force generated by the capillary action

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The Magnetic Motor

• Idea– Utilize a shield to block

magnetic field in desired locations to create a couple on armature

• Results– The field due to the

symmetric array of outer magnets is zero at the center

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Sources

• www.wikipedia.org – Perpetual Motion

• www.answers.com – Perpetual Motion

• www.lhup.edu/~dsimanek– The Museum of Unworkable Devices

• www.kilty.com/pmotion.htm

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Questions???