BUILDING A GENERATORIf we can make a positively-charged object somehow, then we can make negative water droplets. 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 positive to create negative. If we build a second device, we could use the negative to create positive. We could hook the two devices in a loop. 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 will 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 inchesFig. 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.
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.)
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
The upper rings (or cans) must be positioned near the place where the
water droplets break from the rest of the water. If the droplets break
away right at the tip of the nozzle, then put the nozzles within the upper
cans. If a solid stream of water comes from the nozzle and breaks up
further down, then move the nozzels up, so that the water-break spot is
inside the upper inducer cans.
For the Drippers, you can use glass or plastic "pipettes". You want to
have a very small hole, so that the dripper makes lots of tiny droplets.
If you cannot get a pipette, try poking holes in a plastic container. See
Adjust the water flow so it drips VERY fast. The faster, the better.
Even better, use lots of drippers instead of just one.
Once you have the water dripping, you can expect high voltage to
immediately appear. After the device runs for a minute, touch one of the
coffee cans gently with a finger and listen for the tiny snap of a
"static" spark. If you don't hear a spark, the machine is running weakly
or not al all. See the "debugging"" section near the end of this article.
If you can't hear any spark, you can try detecting sparks electronically
with an AM radio. Place a radio a foot away from your generator, tune it
between AM stations (or tune it to a very weak station), and turn the
volume up. Run your Kelvin machine. Touch one of the cans with your
finger and listen to the radio. You should hear a "snap" noise as your
finger touches the metal. Touch one upper can, then the other, then the
first one again. You should hear a "snap" each time. Even when sparks
are too small to hear or see, a radio will sometimes still detect them.
FLASHING A NEON BULB
Once your machine is able to produce sparks, you can also make it flash a
small neon lightbulb. Normal flashlight bulbs won't work, you need a
small neon "pilot light" bulb instead. Obtain an "NE-2" or other similar
neon light, the kind which looks like a short glass tube with two parallel
wires inside and two bare wires sticking out of the glass. Hold the bulb
by one wire, look at the tube, then use the other wire to touch one of the
cans of your Kelvin device. You should see a dim orange flash inside the
bulb. (It might help to turn off the lights and work in a dimly lit
room.) Hold one bulb wire, then use the other wire to touch the positive
can, then the negative can, then the positive, and you should see a tiny
orange flash each time.
CONTINUOUSLY FLASHING BULB
Don't connect the NE-2 bulb directly across the two generator wires. It
will short out the generator and prevent high voltage buildup. You can
make the generator automatically flash the neon bulb by making a "spark
gap". First twist one wire from the neon bulb around one of the
generator's diagonal wires, then bend the wires so other short wire from
the neon bulb is very close to the other generator wire ( but not
touching). Small sparks will occasionally jump across the small gap and
flash the neon. The smaller the gap, the faster (and dimmer) the
flashing. Try a 1/16 inch gap (1 mm) at first. If it works, increase the
distance to get slow, bright flashes. Bend the sharp tip of the wire over
to form a little ring, this sometimes lets the voltage rise higher before
a spark jumps, which lets the bulb flash more brightly.
To "see" the high voltage surrounding the cans, tape some strips of tissue
paper to the cans. Put tape only at the top of each strip of tissue so
the strip hangs down against the side of the can. When the can charges
up, the strips should lift slightly outwards. The higher the voltage, the
farther the strips move. When a spark jumps, the strips jerk because the
repulsion force suddenly becomes less.
The energy that builds up between the cans comes from the falling of the
water. As the stored energy grows, the water has to do more and more work
every time it adds a bit more imbalanced charge to the cans. The
electrified droplets feel a repulsion force as they fall towards the
alike-charged lower cans. As the voltage increases, the droplets will
fall more and more slowly. The sound of the splashing water will change.
The droplets may even start bending their paths, even occasionally falling
EMPTYING THE LOWER CANS
If the device is run for very long, the lower cans fill up. How to get the water out of the cans without discharging them? Here's my addition to the classic Kelvin Waterdropper: use the "faraday ice pail" effect, where a conductive hollow object always has no charge imbalance on its inside. To do this, connect an exit tube inside each lower can as below, so the water DRIPS out (if it falls in a solid stream, the cans will discharge and the generator will stop working.)
|| || || || || || || || ||/\/\/\/\/\/\/\/\/|| || || For best results, no || || sharp edges or burrs || WATER || anywhere. Or, cover || || sharp edges with thick || __ __ || bead of RTV silicone || | | | | || caulk || | | | | || || | U | || || | O | || ====== ====== O Uncharged droplets O exit from bottomFig. 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.
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 | | ikelv.html article for more info \ / 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 | | | | oFig. 5 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.)
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 the drums have sharp edges, and we can't attain millions of volts if the edges are sharp. A foil-covered truck innertube should support about a million volts before air-corona leakage stops the voltage from rising any higher.
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.Fig. 6 GIANT KELVIN DEVICE BUILT FROM SPUN-METAL DONUTS (or tire inner tubes covered with aluminum foil!)
High-velocity shower heads and cross-connecting conductors made from large-diameter pipes will complete the scene above: a "VandeGraaff Generator" version of Kelvin's Thunderstorm apparatus!
NEWS: I suspended a bundt-pan by fishlines, then sprayed water through the center, so that the water did not touch the metal. I used a garden hose with a "water breaker" (a sort of shower head attachment.) I charged up the bundt pan with a 10KV power supply, and then measured the electric current between a collector pot and ground. It was 2.5 microamps! This doesn't sound like much, but it's as much as some VandeGraaff generators can put out.
RUNNING A MOTOR
The above generators can be used to run a motor, if the motor is my Pop
Bottle Electrostatic Motor at:
I find that these small Kelvin Waterdrop Generators are a little too
feeble to keep the motor going continuously. Instead they make it slowly
pulse. They build up a charge imbalance, then the motor starts turning
and rotates a few times. This exhausts the charge imbalance, the motor
stops, then it builds up again and repeats. This happens a couple of
times per minute. A bigger waterdrop generator is needed if you want to
run the bottle-motor continuously.
I put multiple drippers on my waterdrop generator and this improved things
considerably. The best generator uses lots and lots of tiny drops, with
the drops being made as fast as possible. If we use a cluster of dripper
nozzles, the inner ones probably act as electrical shields for the outer
ones. This is bad, since this will prevent the inner ones "seeing" the
charged inducer cans, and they won't make any electrified water. Therefor
a CIRCLE of nozzles is probably best.
I drilled a circle of eight tiny holes in a plastic bowl (using #64 drill
bit), and this gave good results. A crude version of multiple-dripper: use
a soup can, and punch a bunch of holes in the bottom by using a tiny nail.
I've also seen a shower-head thing called a "water breaker" in the garden
supply section of hardware stores. If a circle of tape was stuck to the
center of one of these, it would plug up the middle holes and form a ring
of about 100 tiny water jets.
SPEEDING UP THE RECHARGE
Whenever a spark discharges the generator, it also discharges the inducer
rings. As a result, the generator takes quite a while to "ramp up" to
full voltage again. This is exponential growth, and it's quite slow at
first. There are several possible ways to solve this problem (I haven't
tried them, you be first!) One solution is to insert very large resistors
in series with the wires to the inducer rings (large = thousands of
megohms). Then always discharge only the collectors, not the inducers.
The resistors will keep the inducers from instantly discharging. If the
inducers remain charged, then the generator will quickly recharge with a
fast linear voltage curve rather than a slow exponential curve.
High-value resistors are expensive, so perhaps try making your own
resistors. Use strips of paper with fine lines of india ink (india ink is
Another possibility: rather than using resistors, instead insert high
voltage diodes. For example, use several 7,000-volt microwave oven diodes
in series, available from Allied Electronics. Orient the polarity of
diodes to allow the Inducers to charge but not to discharge. Diodes in
one conductor should point upwards, and in the other conductor should
point downwards. This way the collectors will charge up the inducer
rings, but when you discharge the collectors, the diodes will turn off and
become nonconductors. The excess charge on the inducer rings will remain
high. Also, if you use diodes, the generator polarity would always be
predictable, since the generator would not function if the polarity became
A third method: build a big generator, but don't connect the collectors to
the inducers. Then build a second tiny water-drop generator,
and use it to charge up the inducers of the big generator. Then always
discharge only the collectors of the big generator, and leave the other
metal parts alone.
If you want to use your generator to power a pop-bottle electrostatic
motor, the above idea is the way to go. Build a separate generator to
power the inducers of the larger generator, that way the motor cannot
"short out" the inducer voltage and make everything stop.
Now that I'm thinking about it, here's another type of generator to build:
a half-kelvin device with only two cans. How can it ever work? Simple:
use the screen of a TV
set to charge the inducer! I bet that this would
even work when the humidity is really high. A TV set normally cannot
produce constant electrostatic energy output unless you keep turning it
off and on. But it should be able to supply enough energy to power the
inducer ring on half of a Kelvin's Thunderstorm device.
If your generator really works well, you will see water droplets slow down
and their paths curve upwards! No, this is not antigravity, this is just
electrostatic repulsion. Alike charges repel.
WEIRDNESS: really really gigantic generators
In a private conversation someone told me that there were patents on a
wind generator based upon the Kelvin Generator. Build two big parallel
vertical metal screens the size of outdoor movie theater screens (or
larger). The upwind screen has coarse mesh, the downwind screen has fine
mesh to gather water droplets. Suspend them on insulators which are good
for millions of volts. Charge the upwind screen with a power supply.
Spray a fine mist of water into the screens upwind, and let the wind push
the spray through the screens. The upwind screen will attract imbalanced
charges into the sprayer tips, and the water droplets will have an
imbalanced charge of opposite polarity. The wind takes the place of
gravity in the classic Lord Kelvin device. Wind pushes charged water to
the second, fine-mesh screen. Water droplets touch this screen and
deliver their charge. The wind is slowed by repulsion of the water mist,
the upwind screen uses no current, and the downwind screen puts out
amperes at millions of volts of electrical potential (amps times megavolts
equals megawatts). Simply step down the megavolts of DC, then convert it
to AC. Ta-da, a wind generator with no moving parts! An artificial
thunderstorm, harnessed as a commercial generator, powered by the wind.
If your project will not work, it may be because the humidity is high and
your device is having trouble "deciding" which side should be positive and
which side negative. See my hints about humidity, found at
http://amasci.com/emotor/statelec.html. With Kevin generators
it takes voltage to make voltage. If your device starts totally at zero,
it may take a minute or two to build up to maximum. Therefors give it a
"goose" by holding an electrified object briefly near one of the cans
while the water is running (for example: a balloon, a 2liter pop bottle,
or some styrofoam, each rubbed on hair to electrify them.) This gives the
generator a "kick start."
The two drippers must be neutral, so they need to be connected together
electrically. To make certain they're neutral, connect a grounded wire
to their water supply. These drippers should drip FAST. Many droplets
per second. If your drippers are very slow, then your machine will
charge up very slowly or not at all. To produce a fast drip rate,
usually you need a tiny hole at the end of your water tubes. Plastic or
glass pipettes are the usual way to accomplish this. Also, your machine
will work better if you have many drippers.
If you really cannot get your generator to work, here's a way to "cheat."
Put a piece of aluminum foil
on a TV screen, connect this foil to one of
the inducer cans on your generator, and then turn on the TV. This will
make your generator run, at least temporarily. Don't let any water get
near the TV set!!!
Kelvin Generators usually can tolerate fairly high humidity. Watch out
though. Materials with large internal surface area, such as wood, cloth,
masonite, etc., usually absorb moisture from the air and become slightly
conductive. Therefor, assume that these materials are the same as metal,
and avoid using them as supports or framework when you build this device.
Wood provides a leakage path and shorts out the high voltage. One
experimenter even found that problems were caused by supporting their cans
with insulating blocks glued to a wooden panel. The short lengths of
plastic must not have been sufficiently insulating, and there must have
been a leakage path across the plastic and through the wood. Switching to
all-plastic supports solved their problem.
If acrylic sheets such as plexiglas(tm) or perspex(tm) are not available,
large styrofoam blocks work well as supports. Avoid using solvent-based
glues with styrofoam, it makes it dissolve. The plastic MUST BE CLEAN.
Use new plastic if you can. If you wash the plastic, don't use much soap,
since soap can form a conductive coating. Rinse it and scrub it with lots
of clean water to remove all the soap. If you wash the plastic, then
afterwards dry it thoroughly with an electric hair-dryer gun (but be
careful, don't melt the plastic with too much heat!)
Nylon fishing line makes a good insulating support, especially during high
humidity conditions. Long, very thin supports such as fishing line have
small surfaces and therefor give less surface-current leakage than short,
fat supports or flat panels. Don't use twine or string as supports, of
course, since these materials become too conductive when the humidity is
If humidity is very high, even plastic can become slightly conductive.
This can be temporarily fixed by using an electric hair-dryer gun to dry
the plastic surfaces. Bathe the plastic in hot air for several minutes,
taking care not to heat it so much that it softens! Try testing your
generator again, and it may begin to work.
The water droplets must not touch the inducers. The droplets should pass
through the inducers. The droplets should break free from the water while
they are still inside the inducers. If continuous streams of water (not
droplets) shoot out of the drippers, then move the drippers upwards to
make certain that the droplets break away from the continuous streams
while the droplets are inside the inducer cans.
The water droplets MUST touch the collectors. To start, simply let the
collectors fill up with water. Once you have succeeded in getting sparks
from your machine, then later you can try the trick with the cones of
window screen (see far below.)
To detect the tiniest charge imbalance, build the RIDICOLOUSLY SENSITIVE
CHARGE DETECTOR shown elsewhere on my web pages.
(http://amasci.com/emotor/chargdet.html) This device will
detect a few hundred volts of electrostatic potential at a great distance
from the cans. It is extremely sensitive. The tiniest sparks won't begin
until the cans reach about 1,000v potential, yet the sensor responds to
about ten times less. A sparking Kelvin generator can make the Charge
Detector flash even if it is many feet away.
Don't neglect the balloon trick. If your device doesn't self-start, then
momentarily hold a charged balloon near one of the cans while the water is
running. (Verify that the balloon is really electrified, see if it raises
your arm-hair when rubbed. Sometimes humidity is so high that the balloon
will not aquire an imbalanced charge by rubbing on hair.)
A simple way to detect static charging: place a portable AM radio near the
device, tune it to a blank station, then touch one of the cans with a
finger. If your device is just barely working, there will be an
imperceptible spark. But this will make a loud click on the radio! If
you wear an AM Walkman headphone radio, it will extend your senses so that
you can hear the electromagnetic pulses given off by the tiniest spark.
Become a "Borg" from Star Trek, with the ability to hear electromagnetic
impulses via a biointerface to electronic circuitry (Walkman headphones).
:) Try spending the day wearing AM radio headphones tuned to an empty
spot on the dial, and you will encounter all sorts of interesting
electromagnetic "sounds" in the environment. You'll hear the "crack"
noises of distant lightning even when the thunderstorms are too far away
to hear the thunder. Electric fences in countryside farms make a periodic
clicking. The overhead wires from electric city buses make all sorts of
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OTHER ARTICLES: 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: keywords: Kelvin's Thunderstorm (google) Kelvin's Thunderstorm davidwilliamson Sparking Buckets (Bizarre stuff made in your kitchen) 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/articles/airwells.htm Inline version of "Kelvin's Thunderstorm" electrostatic generator: http://amasci.com/emotor/ikelv.html
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