Lord Kelvin Electrostatic Generator

Potential Alternative Energy Applications:•Charging a battery, •Providing energy for electrolysis (for Hydrogen Fuel Cell), •Powering a Light or Motor.

A Scorpacuda Presentationhttp://www.scorpacudas.com

July 2007

This is Lord Kelvin’s Electrostatic Generator

What is it?

• A Lord Kelvin Electrostatic Generator is a very simple high-voltage generator which has no moving parts and is powered by the energy of falling water.

• Gravity provides the force to make the water move.

• Energy is needed to get the water to a height higher than the input. You can’t get energy from a system without doing work on the system.

How does it work?

• Water normally has zero net electrical charge because it contains a vast number equal and opposite charges.

• It is easy to create an imbalance of charges in water because water is full of movable electric charges (called ions). Water (H2O) has H+ and OH- ions.

• You can charge water by holding a charged object, such as a comb, near the water. That object will attract the "unlike" charges to the water's surface, and repel the "alike" charges away deeper into the water.

How does it work?• A positively charged object will attracts

the water's negative ions and repels the positive ions.

• The tip will hold an excess of negative ions and an equal amount of positive ions are repelled to the other end of the dripper.

• When the water drop detaches from the tip of the dripper, it carries a negative electric charge.

• The trapped negative charge in the falling water droplet leaves the dripper slightly positive.

• The container collecting the falling droplets becomes negatively charged.

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Surface is Positively Charged

Comb is Positively Charged

Collector isNegativelyCharged

Dripper tips& drops areNegativelyCharged

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Ref: http://amasci.com/emotor/kelvin.html

Kelvin Water Dropper

Kelvin Water Dropper

Charging a Battery• Can the Lord

Kelvin electrostatic generator be used to charge a supercap 9V battery?

Electrolysis• We used solar cells for electrolysis.  Hydrogen is separated from

oxygen in water into different holding tanks.  The hydrogen is used by the hydrogen fuel cell. 

• The solar cell can't produce hydrogen as quickly as it is consumed.  It took 20 minutes with intense light and the solar cell to create enough hydrogen gas for 5 minutes of running the car.

• We are looking into other ways to make hydrogen 'on the fly'.  We might use the water from the hydrogen fuel cell to create electricity.  Lord Kelvin showed a way to make electricity from water and gravity. 

Cyclic Water Concept

• Process Flow Concept:1. H2 and O2 gases is created from a reservoir of water through

the electrolysis process.2. H2 and O2 gas is used by the hydrogen fuel cell to produce

water and energy.3. The water is used with gravity to generate electricity from the

Lord Kelvin device.4. Charged water is dumped to a lower gravitational potential into

tanks that create a net zero charge water.5. Water in these tanks undergoes electrolysis using electricity

from the Lord Kelvin device.• How can we make this work?

– How many nozzles do we need?– Can we calculate the maximum rate of H2 we can produce?– Can we keep the positive/negative electrodes consistent?

Powering a Light or Motor

Some References• J2-02: KELVIN ELECTROSTATIC GENERATOR • Hobart Mason, A text-book on Static Electricity, McGraw Publishing Co., New York, 134-137, (1904), 52. The

Dropping Generator, pp. 135-137. • C. Z. Van Doorn, Demonstration of Electrostatic Generator Principles, AJP 37, 225, (1969). • Harry F. Weiners, Physics Demonstration Experiments, Electrostatics, Library of Congress No. 69-14674, Ronald

Press Co., New York, 847-850, (1970). • Menno Fast, Electrostatic Lobby Display, TPT 10, 100-101, (1972). • Markus Zahn, Self-Excited ac High Voltage Generation Using Water Droplets, AJP 41, 196-202 (1973). • Lester Evans, J. Truman Stevens, Kelvin Water Dropper Revisited, TPT 15, 548-549, (1977). • William Blunk, Doing Physics: Kelvin electrostatic generator workshop, TPT 20, 412-413 (1982). • Michael Sady, The Kelvin Water Dropper: An Elementary Experience, Phys Teach 22, 516, (1984). • Joe Pizzo, "Ting-A-Ling" Machine, TPT 26, 304-305, (1988). • A. D. Moore, Electrostatics, Doubleday & Co., New York, 174-179, 204-211. • Catalog Description of Apparatus, Cat. No. 78680 Electrostatic Generator, Cenco Scientific Co. • Instructions, Catalog No. 78680 Electrostatic Generator, Cenco Scientific Co. • Meiners, Physics Demonstation Experiment, Section 29-1.23, pp. 247-250. • Paul Chagnon, Animated Displays VI: Electrostatic Motors and Water Dropper, TPT 34, 491-494 (1996). • Se-yuen Mak, The Kelvin Water-Drop Electrostatic Generator-An Improved Design, TPT 35, 549-551 (1997). • Gorazd Planinsic and Tomaz Prosen, Conducting rod on the axis of a charged ring: The Kelvin water drop

generator, AJP 68, 1084-1089 (2000).

http://www.physics.umd.edu/lecdem/services/refs/refsj.htm#J2-02