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"Kelvin's Thunderstorm" Lord Kelvin's water-drop electrostatic generatorBill Beaty, 1995

NOTE: avoid using wood to support metal parts! See "debugging" notes at the end. See FURTHER INFO at end too.
It is possible to build a very simple high-voltage generator which has no moving parts and is powered by the energy of falling water. By dribbling water through some old soup-cans, several thousand volts magically appear. The "magic" lies in the fact that water (as well as everything else!) is made of vast quantities of positive and negative electric charge in perfect balance. It's not too hard to cause an imbalance. Water normally has zero net electrical charge because it contains equal and opposite charges. "Kelvin's Thunderstorm" is a gravity-powered charge un-canceller.

```

+  + +
+|||||| +
||||||
||||||   Water
||||||   Dripper
||||||
Negative charge is   ||||||
'induced' at tip      \  /
of dripper           - || -
- _ -

_           + + + + + + +
-o-        + -------------- +
-        + |       A      | +
+ |  Positively  | +
_        + | Electrified  | +
-o-       + |    Object    | +
-        + |              | +
Negatively                 + |              | +
electrified                 + -------------- +
water droplets    _           + + + + + + +
-o-
-

-             -
- |               | -
|               |     Collector-can
- |--__----____---| -   becomes Negative
|               |
- |               | -
|               |
- |_______________| -
-    -     -

```
Fig 1. WATER DROPLETS BEING ELECTRIFIED BY "INDUCTION"

THE BASIC THEORY

Even though water has no overall electric charge, it is full of movable electric charges (called ions). Half of the water's charges are positive and half are negative. It is not hard to separate these charges; simply hold an electrified object near the water. The electrified object will attract the "unlike" charges to the water's surface. It will also repel the "alike" charges away, deeper into the water.

In the above diagram, the positive object attracts the water's negative ions and repels the positive ions. This draws an excess of negative ions into the tip of the water dripper, while repelling an equal amount of positive ions off to the other end of the dripper. When the water drop detaches from the tip of the dripper, an overall negative electric charge is still trapped in the droplet. The falling water droplet carries away negative charge, leaving the dripper slightly positive. If we catch the falling droplets in a container, the container will become negatively charged.

In the above diagram, negative water droplets will be continuously created forever as long as the water flows. However, this process does not exhaust the imbalanced charge on the positive object. Sounds like perpetual motion, eh? Actually no. The electrical energy is being created by the work that gravity does in pulling the negative droplet away from the grounded dripper, and away against the attraction of the positive object. The electrical attraction-force from the positively-charged object keeps the tip of the dripper charged negatively, but the positively charged object does not supply energy. YOU supply the energy, since you LIFT the water to a height to fill the dripper. It's like the generator in a hydroelectric dam, but without the turbine or the spinning coils or magnets. The water itself becomes the moving parts of an electric generator.

(Note: the charge polarities can easily be reversed. If the above "object" is made negative, the droplets would come out positive.)

BUILDING A GENERATOR

If somehow we can make a positively-charged object, then we can create negative-charged water. But where can we get a positive object? If there was some way to CHANGE the negative charge on the water into a positive charge, then we could use the water to charge up it's own "positive object". We would then have a a self-sustaining generator.

There's a simple way to do this: build TWO water-drop devices like the one in figure one! See the trick? The device in figure one uses a positive object to create negative water. It uses "plus" to create "minus." If we build a second device, we could use the "minus" from the first one to create "plus." Then we could hook the two devices in a circle. The first one would create an imbalance of negative charge, which could be fed to the second one which would create an imbalance of positive charge, which would be fed back to the first one again. It might sound crazy, but it really works.

We'll build two of the drippers in Fig. 1, set them side by side, then collect the electrified water droplets from one side and use them to electrify the "charged object" on the other side, and vice versa. We'll cross-connect the lower and upper parts with wires. One side will have a positive "object" and will make negative droplets, while the other side will have a negative "object" and will make positive droplets. We'll also connect the drippers together so they remain neutral. Then we will have a self-sustaining electrical reaction.

```
_______________________
_   __________________  \  Water Supply
\ \                   \ \
\ \                   \ \
\ \                   \ \ Drippers (metal,plastic,glass)
||                    ||
||                    ||
||                    ||  Connect the water supply to a
||                    ||  metal faucet using a wire, or
||                    ||  to the screw on an electric
||  Wire not shown,   ||  outlet or wall switch.
see next diagram
(below)
|    |                 |    | Bottomless metal coffee cans,
|    |                 |    | or wire rings, or bundt pans,
|    |                 |    | or metal disks with large holes
|    |                 |    | (supported by insulating rods.)
|    |                 |    | Called "Inducers."  These
act as the "charged object."

|    |                 |    |  Metal cans on insulators
|    |                 |    |  (styrofoam? insulating rods?)
|    |                 |    |  The "Collectors."
|    |                 |    |
|____|                 |____|
|  |                   |  |   The "inducers" and "collectors"
|  |                   |  |   should be separated from each
|__|                   |__|   other by several inches

```
Fig. 2 TWO DROPLET-CHARGERS PLACED NEAR EACH OTHER (see below for wires)
 See Fig. 3 below. Wires connect the two sides together. The negative droplets touch the lower Collector-can of the first side. The collector can is electrically connected to the upper negative Inducer of the second side. The negative Inducer will cause the second side to make some positive droplets. The positive droplets of the second side will touch the second lower collector can, and this will charge the upper Inducer can of the first side positively. (This makes the first side produce negative droplets.) The grounded drippers must be connected to each other and to ground. See Fig. 3 below to see how the wires connect things together. Highly recommended: ELECTROSTATICS by A. D. Moore (lots of projects), also others SELF-STARTING But where does the first charge come from? In fact, if you build such a device, it will usually create voltage all by itself, spontaneously, without being pre-charged. During dry conditions everything near the generator ends up with a tiny electric charge just from being handled. If one of the upper cans is slightly negative, it will cause the water to have imbalanced positive, which will start up the other side of the generator, which will make the charge on the negative side become larger, etc., over and over. It's like balancing a penny on edge: it's hard to start out with a perfect balance, and usually it falls one way or the other. Same with this generator. If there's a tiny electrical imbalance at the start, the generator will amplify it over and over, and the voltage will "fall over" to either one polarity or the other. A high voltage will magically appear from nowhere. (But nobody knows which side will start out positive and which will be negative.) Here's another viewpoint: each section is an electronic inverter! If we place a negative voltage on the inducer-ring, a positive voltage will then appear on the water droplets, and upon the lower can. By cross-connecting two such "inverters," we form a flip-flop circuit. When first turned on, it randomly "decides" to store either a logic-high or a logic-low. Ah, but what would happen if we instead built THREE of these segments? And connected them in a loop? Why, then it's unstable, and must form an electronic ring-oscillator. And that's exactly what happens: "Euerle's dynamo" is a Kelvin Thunderstorm with three segments hooked in a loop, and producing some (very slow) three-phase AC output. See Self-excited ACHV Generation Using Water Dropelts AJP 1973 CONSTRUCTION The metal parts of the generator must be supported with insulating materials. A large vertical sheet of acrylic plastic works well. So does styrofoam plastic. Don't use wood for the supports, it's too conductive. Fasten the collectors and inducers to the plastic sheet with screws or silicone caulk, or make holes in the sheet and tie them to the sheet with string or wire. Some people have used plastic rods or plastic strips to support things. Other people use plastic water pipes. The plastic must be clean and dry. The inducers and collector cans must be spaced away from each other by several inches horizontally and vertically. The lower collectors must be kept away from the table surface. Bare wires are used to cross-connect the four cans. These two diagonal wires must be far from any other conductive object, and the wires must not touch together. Use bare wire, this will let you create sparks between the wires, or to later flash a NE-2 neon bulb. Connect the ends of the diagonal wires directly to the metal of the cans. If you use plastic-covered wire, strip off the plastic coating from an inch of each end of the wire. You can use tape to hold the wire against the metal, as long as the wire touches the bare metal directly (not, for example against the painted part of a coffee can.) Alligator clipleads (bought from Radio Shack stores) work well for this. Or poke a hole in the metal near the edge of the can, stick the wire through the hole, and bend it and tape it so it doesn't fall out.
```___________________________
_   _______________________ \
\ \                       \ \
\ \                       \ \
\ \                       \ \
||                        ||
||                        ||
||                        ||
||                        ||

|  o |                     | o  |
|    |                     |    |
|  o |+    +         -   - | o  |
+ |    |----\            /---|    |  -
|  o |  +   \ +    - /  -  | o  |    (no connection
+ \    /                  between the
o            C/           o        crossed wires!)
- |    | -       / \       + |    | +
- |  o | -   - /   + \     + | o  | +
|    |_____/         \_____|    |
- |----|   -             +   |----| +
|____|                     |____|
|  |                       |  |
|  |                       |  |
|__|                       |__|

```
Fig. 3 LORD KELVIN'S THUNDERSTORM, W/WIRES SHOWN

```
||                 ||
||                 ||
||                 ||
||---__-__---___---||
||                 ||   For best results, no sharp
||                 ||   edges or burrs anywhere.
||     WATER       ||   Or, cover sharp edges
||                 ||   with thick bead of
||     __   __     ||   RTV silicone caulk, or
||    |  | |  |    ||   use heavy Tygon hose,
||    |  | |  |    ||   slitted lengthwise
||    |   U   |    ||
||    |   O   |    ||
======       ======
O
Uncharged droplets
O  exit from bottom

=============================================================

o  o
o  o
o      holes cut above, below
__----- o  o  -----__
_/         o  o        \_
_/             o           \_
/      |      o  o     |      \
|       |--___----__---_|       |    HOLLOW METAL SPHERE
|         |             |         |  ( 14" SS bowls fm/Ikea,
|   plast. \_         _/          |    Blanda Blank(tm)  )
|   bucket   \_______/            |
|             o   o             |
\_           o o            _/
\__        o   o       __/    plastic bucket hung by
--____  o o   ____--       heavy fishing line, with
o   o              many tiny holes drilled
Water never          o o                in center bottom
touches sphere       o   o
o o
o   o
o
```
Fig. 4 REMOVING THE WATER FROM THE LOWER CANS

 Or, even simpler, install a cone-shaped piece of metal window screen inside a bottomless can, so the water droplets touch the screen and continue through. Make sure the screen is centered vertically within the can, so that the point of the cone doesn't extend past the lower lip of the can. Don't let the water drip from the edge of the can, otherwise it will carry charge away with each drop. "INLINE" VERSION With a little catcher-tray and a fountain pump, you can make the system recirculate. Or, you can stack all four parts of one Kelvin device in a single row, for an in-line waterdropper generator. See my article on "Inline Kelvin Thunderstorm Device" found on my site at Note that the Inline version is more tricky to make work. Build the above device first before attempting the one below.

```
\ \
\ \
\ \
||
Grounded     ||
Dripper     ||
||
o
o
|   |
Neg     |   |
can     | o |
|   |

Pos      |   |
can      |...|
w/screen  |   |     Connecting wires not shown, see

\    /    Connect pos to pos, neg to neg
Grounded     \  /
Funnel        ||
o
|   |     Note that this is a more advanced
Pos     |   |     project, and is more difficult to
can     | o |     debug than the side-by-side version.
|   |

Neg      |   |
can      |...|
w/screen  |   |
|   |
o
```
Fig. 5  l IN-LINE VERSION (wires not shown)

 The water supply need not be a "dripper", it can be a high velocity spray, as long as the water jet divides into droplets, not a contiguous stream. And multiple jets can be used, sort of like a shower head. The faster the flow and the larger the number of separate streams, the higher the total output current. (Higher current gives faster recharge rate after a spark, and it lets the generator self-start more reliably when humidity is high.) GIGANTIC VERSION Kelvin's waterdropper I've always wanted to build a gigantic version like the one below, with hollow metal toroids. (Use halves of VandeGraff spheres, the halves with the holes). Or maybe use metal 55-gal drums. But those drums may have sharp edges, and we can't attain millions of volts if the edges aren't bulbous. A foil-covered truck innertube should support about a million volts before air-corona leakage stops the voltage from rising any higher. Or do as Tesla-coilers do, and make a skeletal torus from bent, coiled pipe.

```                                            Four tori
\\                           \\     (shown cross-
\\                           \\    sectional)
\\                           \\
||                           ||
||                           ||   water spray
||                           ||
___           ___             ___           ___
/   \         /   \           /   \         /   \
|     |       |     |         |     |       |     |
\___/         \___/           \___/         \___/

___           ___             ___           ___
/   \         /   \           /   \         /   \
|     |\     /|     |         |     |\     /|     |
\___/   \_/   \___/           \___/   \_/   \___/

Conical screens in lower torii touch droplets and
release, discharging them.  Entire screens must be
deep within the "hole" of each donut so the torus can
shield the departing water droplets from the electrical
fields on the outside.  If you can see the screens
sticking out, your device will barely work.
```
Fig. 6 GIANT KELVIN DEVICE BUILT FROM SPUN-METAL DONUTS
(or foil-covered inner tubes, or a spiral of pipe.)

```

_____             _____
/     \           /     \
|       |         |       |
|         |\/\_/\/|         |   LOWER TORUS WITH
|         |       |         |   DROPLET-TOUCHING METAL
|       |         |       |    SCREEN ACROSS THE
\_____/           \_____/     DONUT-HOLE

```
```

```

LOOKING FOR BOOKS? Try searching amazon.com:

(try "science fair" too)

```
OTHER ARTICLES HERE:

'Inline' version, stacked sections

General debugging notes for electrostatics

Solving humidity problems for VDG machines

VandeGraaff Machines (big sparks)

Tesla Coils (bigger sparks)

What if lightning was slow?

REFERENCES:

Kelvin's Thunderstorm davidwilliamson

Solaris Kelvin Devices (several)

Version of above article

UMICH w/diagram

John D'Mura's device

UMD photo

Scifun

UNIMELB diagram

Diagram w/Leyden Jars

THE PHYSICS TEACHER (magazine), May 1988, pp304-306, The Ting-A-Ling
Machine, by Cliff Bettis   (uses mixing bowls)

THE PHYSICS TEACHER (magazine), February 1972, pp100-101, Electrostatic
Lobby Display, by M. Fast   (uses coffee cans)

Scientific American Magazine  June 1960, THE AMATEUR SCIENTIST, by C. L.
Stong, page 175

Alvin Marks' "Power Fence", an HV wind power generator with no moving
parts http://www.rexresearch.com/airwells/airwells.htm

Inline version of "Kelvin's Thunderstorm" electrostatic generator:
http://amasci.com/emotor/ikelv.html

```

Want books? Try searching amazon.com:

(try "science experiment project" too)

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