# Perpetual motion

(redirected from Perpetual energy)
Also found in: Dictionary, Thesaurus.
Related to Perpetual energy: perpetual motion

## Perpetual motion

The expression perpetual motion, or perpetuum mobile, arose historically in connection with the quest for a mechanism which, once set in motion, would continue to do useful work without an external source of energy or which would produce more energy than it absorbed in a cycle of operation. This type of motion, now called perpetual motion of the first kind, involves only one of the three distinct concepts presently associated with the idea of perpetual motion.

Perpetual motion of the first kind refers to a mechanism whose efficiency exceeds 100%. Clearly such a mechanism violates the now firmly established principle of conservation of energy, in particular that statement of the principle of conservation of energy embodied in the first law of thermodynamics. (Indeed, the first law of thermodynamics is sometimes stated as “A perpetuum mobile of the first kind cannot exist.”). See Conservation of energy

Perpetual motion of the second kind refers to a device that extracts heat from a source and then converts this heat completely into other forms of energy, a process which satisfies the principle of conservation of energy. A dramatic scheme of this type would be an ocean liner, which extracts heat from the nearly limitless oceanic source and then uses this heat for propulsion. This type of perpetual motion is, however, precluded by the second law of thermodynamics which is sometimes stated as “A perpetuum mobile of the second kind cannot exist.”

The third type of perpetual motion is, in contrast to the two types described above wherein useful output was the goal, merely a device which can continue moving forever. It could result in actual systems if all mechanisms by which energy is dissipated could be eliminated. Since experience indicates that dissipative effects in mechanical systems can be reduced, by lubrication in the case of friction, for example, but not eliminated, mechanical perpetual motion of the third kind can be approximated but never achieved. An example of a genuine case of this kind occurs in a superconductor. If a direct current is caused to flow in a superconducting ring, this current will continue to flow undiminished in time without application of any external force. See Superconductivity, Thermodynamic principles

References in periodicals archive ?
During the agreement term, the diocese will benefit from the use of solar renewable energy while Perpetual Energy Systems retains ownership of the system as well as the renewable energy certificates and carbon credits," said Mike Maley, president and CEO of Perpetual.
winery is an honor for us," says Laurance Friedman, co-chair of Perpetual Energy Systems.
para]]CALGARY, May 20, 2015 /PRNewswire/ - (TSX: PMT) -- Perpetual Energy Inc.
a leader in the full-service development, installation and financing of solar electric systems for commercial, government and residential customers, and its joint venture partner Perpetual Energy Systems LLC (Perpetual), a comprehensive financier of solar powered renewable energy systems, today announced it will participate in a groundbreaking ceremony to begin the installation of a large scale solar electric system supporting Maryland's St.
CALGARY, April 13, 2015 /PRNewswire/ - (TSX:PMT) - Perpetual Energy Inc.
This has truly been a collaborative effort and I applaud the Maryland Energy Administration, Standard Solar, Incorporated, Perpetual Energy Systems, LLC, Southern Maryland Electric Cooperative, and the staff of St.
CALGARY, Canada, February 9, 2011 /PRNewswire/ -- Perpetual Energy Inc.
Perpetual Energy Systems, LLC (Perpetual), a national power purchase agreement (PPA) provider/financier of solar powered renewable energy systems, today announced the completion of a 1.

Site: Follow: Share:
Open / Close