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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
8
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
9
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