Hello Everyone,

I haven't done much with the VDG's lately but I have been working on my static
electric motor. It is a simple drink bottle with aluminum tape for the plates.
There is a small Phillips head screw in the cap and a hole drilled in the bottom
for the main support; A metal rod with the top ground to a point. Around it are
two aluminum plates with one side terminating to a point which points at the
bottle (rotor).  There are pics in the 'Todd's Pics' folder. The File section
has some video of it running.  I had built this awhile ago and meant to upload
pics and a vid of it, but I hadn't got around to it.

Well the other day I wondered if the device would run with a neon light with a 1
megaohm resistor in series between two consecutive plates. Or would this just
draw all the current and not allow it to deliver enough charge on the plates to
allow the rotor to turn.  Well as it turns out I didn't even need the resistor
as the video shows it runs fine with the neon lights attached.  The humidity was
a little higher today so the running speed was not as high as I achieved
yesterday, but was adequate to show that it works.

I haven't hooked it up to the VDG yet and would probably blow out the neon
lights with the 200k-300k my large VDG outputs. But I will let you all know how
I make out.

Sorry for the low quality of the vids but our Digital camera apparently grew
legs, went for a walk and got lost (grrrr).

Well anyway, I hope you like the pics and vids. Once refined this could make a
neat mad scientist prop. I am working on having the axle suspended by a magnet
so that I can take the rotor out to show that there is no physical connection to
the power source and have it start turning and lighting seeminginly by itself.

Have fun and be safe
Todd

Here, here!

I've been silently lurking, getting together parts to build a VdG, following the
posts here, absorbing information. This list is the best repository of VdG info
out there.

Steve Greenfield

--- In VanDeGraaffGenerator@yahoogroups.com, "jacobsmach" <hihoag@...> wrote:
>
> Even though there has been very little message traffic here for a while, the
archives contain a wealth of knowledge that is as valid now as ever. While I am
disappointed with the lack of new posts, I still enjoy the old ones, which can
be searched for specific topics like rollers, belts, spheres, bearings, motors,
and others. Just about any post from Dick Linder, a semi-retired member, is sure
to have good information and is a recommended search for all building a VDG.
>

Even though there has been very little message traffic here for a while, the
archives contain a wealth of knowledge that is as valid now as ever. While I am
disappointed with the lack of new posts, I still enjoy the old ones, which can
be searched for specific topics like rollers, belts, spheres, bearings, motors,
and others. Just about any post from Dick Linder, a semi-retired member, is sure
to have good information and is a recommended search for all building a VDG.

Ned,
I have also been using skateboard wheel bearings and while they eventually will
leak, they usually start to get 'loud' before they leak so check them for
problems when they start making noise

Todd


--- In VanDeGraaffGenerator@yahoogroups.com, "Edward" <ned.welch@...> wrote:
>
> So fall is here, the humidity is falling -- time to fire up the VDG.
>
> I've been thinking of upgrading my VDG, which currently runs at about 1000 RPM
using nylon bushings to control the friction between the roller shafts and their
mountings.
>
> I'd like to push the speed up to 2000-3000 rpm, but think that will require
real bearings.
>
> McMaster Carr has a pretty wide variety, but many come pre-greased.  I've read
here that grease is a big no-no inside a VDG.  Does anyone know how likely
bearing lubricant is to "escape" and contaminate VDG rollers?  Would "sealed"
bearings prevent this problem?
>
> Thanks & regards,
> Ned
>

 
 

So fall is here, the humidity is falling -- time to fire up the VDG.

I've been thinking of upgrading my VDG, which currently runs at about 1000 RPM using nylon bushings to control the friction between the roller shafts and their mountings.

I'd like to push the speed up to 2000-3000 rpm, but think that will require real bearings.

McMaster Carr has a pretty wide variety, but many come pre-greased.  I've read here that grease is a big no-no inside a VDG.  Does anyone know how likely bearing lubricant is to "escape" and contaminate VDG rollers?  Would "sealed" bearings prevent this problem?

Thanks & regards,
Ned

  
    

--- In VanDeGraaffGenerator@yahoogroups.com, "Edward" <ned.welch@...> wrote:

> McMaster Carr has a pretty wide variety, but many come pre-greased.  I've read
here that grease is a big no-no inside a VDG.  Does anyone know how likely
bearing lubricant is to "escape" and contaminate VDG rollers?  Would "sealed"
bearings prevent this problem?

Grease and oil are not a so big problem. It's easy to clean eventual spills.
Sealed ball bearings don't leak. I have used ball bearings in several VDG
generators without problem.

A weird problem with rollers: I was having problems with the belt slipping on
the driving roller. I had then the idea of scratching the roller to make its
surface rough and grab better the belt. The idea worked. The belt ceased to slip
and the machine continued to work as before, if not better.
But after some time I noticed that the belt was full of small holes, possibly
caused by concentrated electric field (and mechanical effects) in the rough
roller. I will have to replace the roller and the belt, and look for another
solution...

So fall is here, the humidity is falling -- time to fire up the VDG.

I've been thinking of upgrading my VDG, which currently runs at about 1000 RPM
using nylon bushings to control the friction between the roller shafts and their
mountings.

I'd like to push the speed up to 2000-3000 rpm, but think that will require real
bearings.

McMaster Carr has a pretty wide variety, but many come pre-greased.  I've read
here that grease is a big no-no inside a VDG.  Does anyone know how likely
bearing lubricant is to "escape" and contaminate VDG rollers?  Would "sealed"
bearings prevent this problem?

Thanks & regards,
Ned

--- In VanDeGraaffGenerator@yahoogroups.com, "mebikerider" <david_beals@...>
wrote:
>
> I check in from time to time.
>
> I'm more of a Wimshurst guy, though. Still experimenting around...
>
> I attached a flat brass plate to one of my Wimshurst accumulator terminals and
suspended a 1 by 3 inch aluminum foil sheet against it. When you start cranking
the Wimshurst, the foil swings out like an electroscope! It's quite sensitive;
with just a crank or two, the foil starts to swing out, well before any sparking
occurs. Very nice as a voltage indicator.
>
> It shows some of the odd polarity things the machine does. Crank a few turns,
then stop, and the foil swings out and stops at maybe a 45 degree angle. Touch
the brass plate and the foil drops to neutral. But then touch the other
accumulator, and the foil jumps out again!

This happens because of the interconnected Leyden jars. Probably the
interconnection is floating, and so if you ground one terminal you increase the
voltage in the other.
>
> Sure would be nice to calibrate it with some sort of meter face in volts.

Make something like this:
http://www.coe.ufrj.br/~acmq/2henley.jpg

I check in from time to time.

I'm more of a Wimshurst guy, though. Still experimenting around...

I attached a flat brass plate to one of my Wimshurst accumulator terminals and
suspended a 1 by 3 inch aluminum foil sheet against it. When you start cranking
the Wimshurst, the foil swings out like an electroscope! It's quite sensitive;
with just a crank or two, the foil starts to swing out, well before any sparking
occurs. Very nice as a voltage indicator.

It shows some of the odd polarity things the machine does. Crank a few turns,
then stop, and the foil swings out and stops at maybe a 45 degree angle. Touch
the brass plate and the foil drops to neutral. But then touch the other
accumulator, and the foil jumps out again!

Sure would be nice to calibrate it with some sort of meter face in volts.

--- In VanDeGraaffGenerator@yahoogroups.com, Earl Stirling <estirling@...>
wrote:
>
> I monitor and occasionally contribute.
>
> I keep our 3' generator running.
> ----
> Earl Stirling
> Swiss Army Knife
> e x p l  O  r a t o r i u m
> 3601 Lyon St
> San Francisco CA 94123
> +1.415.353.0401
>
>
> On Mon, Sep 7, 2009 at 1:42 PM, toddjwood <toddjwood@...> wrote:
>
> >
> >
> > Is there anyone else still monitoring this group or still working on VDGs?
> > Todd
> >
> >
> >
>

--- In VanDeGraaffGenerator@yahoogroups.com, "toddjwood" <toddjwood@...> wrote:
>
> Is there anyone else still monitoring this group or still working on VDGs?
> Todd
>
Most certainly, I've just joined the the group and am finding the information in
the posts invaluable in setting up my VDG. I am still a beginner at high-voltage
stuff so all the discussions are most helpful. I will post some photos of my VDG
when I have time. It's quite vintage with a 5 1/2 sphere, made by MLI - anyone
know of this model or what MLI stands for ( I assume the LI stands for
Laboratory Instruments). Thanks for all the tips. Ian. UK.

 

Is there anyone else still monitoring this group or still working on VDGs?
Todd

--- In VanDeGraaffGenerator@yahoogroups.com, "toddjwood" <toddjwood@...> wrote:
>
> Is there anyone else still monitoring this group or still working on VDGs?
> Todd
>
I'm a newbie to this group, and am working on rounding up materials to build
one.
~Travis

I keep checking in but an injury has changed all my priorities.

I can't work on fun stuff right now but I have picked up a couple of A.D.
Moore's books on creativity and electroststics.

I'll be re-reading those and planning my next adventure.  It will probably
utilize bed frame rollers and Ikea rimless stainless steel bowls for a sphere.

I have an old sewing machine motor to drive it.

----- Original Message -----

From: Trevor Hannam

To: VanDeGraaffGenerator@yahoogroups.com

Sent: Tuesday, September 08, 2009 7:35 AM

Subject: {Disarmed} RE: [VanDeGraaffGenerator] Is anyone still active in this group?

 

Geez

It has been a while Todd – I am still operating my uniot and about to make another small battery operated portable one

Trevor

From: VanDeGraaffGenerator@yahoogroups.com [mailto:VanDeGraaffGenerator@yahoogroups.com] On Behalf Of toddjwood
Sent: Tuesday, 8 September 2009 6:42 AM
To: VanDeGraaffGenerator@yahoogroups.com
Subject: [VanDeGraaffGenerator] Is anyone still active in this group?

 

Is there anyone else still monitoring this group or still working on VDGs?
Todd

Is there anyone else still monitoring this group or still working on VDGs?
Todd

Hi Paul,

This is a bit off topic for this mailing list. You may wish to consider
joining the Tesla Coil Mailing List (TCML) at www.pupman.com for
extended Tesla Coiling information/dialog.

Once you cool down the gap electrodes, they will (re)fire at a higher
voltage, providing more energy to your tank circuit each time your gap
(re)fires. This creates longer and hotter output sparks from your
bipolar Tesla coil. The "S" shaped discharge might be due to electrical
field effects, but it's more likely due to stray air currents from your
vacuum cleaner "blowing" the Tesla Coil sparks.

Bert
--
***************************************************
We specialize in UNIQUE items! Coins shrunk by huge
magnetic fields, Lichtenberg Figures (our "Captured
Lightning") and out of print technical Books. Visit
Stoneridge Engineering at http://www.teslamania.com
***************************************************


mrapol wrote:
> OK, so now I've seen something I've never heard of or seen before.
> The simple two post spark gap I made for my bipolar Tesla coil runs
> hot (not surprising), so I was casting about for a simple way to
> cool. I got a small vacuum cleaner with a reversible hose, and I
> switched it from intake to outtake. It blows a fairly strong stream
> of air out. I fired up the coil and directed the stream of air at the
> spark gap.
>
> Whoa! The buzzing, flickering spark turned into a bright, steady
> fireball, and the coil's discharge took on a distinctly thicker,
> brighter spark--in the shape of a sideways S, or sine wave! Is this
> typical for a forced air gap coil? It's very striking, a blazing hot
> purple S sizzling between the terminals.
>
> Paul
>

OK, so now I've seen something I've never heard of or seen before. The simple
two post spark gap I made for my bipolar Tesla coil runs hot (not surprising),
so I was casting about for a simple way to cool. I got a small vacuum cleaner
with a reversible hose, and I switched it from intake to outtake. It blows a
fairly strong stream of air out. I fired up the coil and directed the stream of
air at the spark gap.

Whoa! The buzzing, flickering spark turned into a bright, steady fireball, and
the coil's discharge took on a distinctly thicker, brighter spark--in the shape
of a sideways S, or sine wave! Is this typical for a forced air gap coil? It's
very striking, a blazing hot purple S sizzling between the terminals.

Paul

Recent developments . . . I fried one of the 20KV Chinese radio capacitors.
There was a flash, and the coil went dead. I checked the cap with a meter and
it's toast.

Turns out they're not polypropylene, as I first reported, but polystyrene. A
pair of the same caps in series work beautifully, but they don't give the
bright, noisy discharges the single cap did.

Tonight I hooked up my Leyden jar battery (14 Leyden jars, 500pF capacitance
each) and the coil works OK, not as well as with the radio caps. It is an eerie
sight though. The jars are made from polypropylene canisters with aluminum soda
cans inside (see http://www.instructables.com/id/Soda_Can_Leyden_Jar/. When the
NST fires up there are tiny but steady arcs between the outside coatings and
bluish coronas inside the plastic tops. Couple that with the glare of the static
spark gap and the discharge at the terminals, and it becomes quite a show.

PBT

After tinkering with components for a year, I finally lashed together my first
Tesla coil yesterday. Inspired by a design I saw in the Lindsay Pubs. reprint
THE BOY ELECTRICIAN, I built a bipolar design, that is with a horizontal primary
and secondary, with brass terminals coming from each end of the secondary. In an
effort to keep wood and ferrous metals out of the device, I built the frame out
of 1/2 inch PVC. The secondary form is a heavy cardboard tube, well dried and
shellacked, wrapped with 11 inches of 24 ga magnet wire (250 feet of wire in
all). The primary is formed on a so-called "2 inch" PVC pipe coupling, actually
2.75 inches in diameter. It has 9 turns of insulated 12 ga. wire. I've been
trying various capacitor arrangements but the best so far is the simplest,
namely a single 4000 pF, 20KV polypropylene radio capacitor. Power is supplied
by a Allanson NST, 7.5KV, 30 mA. I have four identical caps, so I am going to
try various combinations. I have a program called TeslaMap which recommends
about 15 nF for this configuration.

I was frankly startled by how well it works. I have a smaller Tesla coil I
bought from Ken Scott, and I have seen other coils in operation, but my
"plumber's nightmare" coil is very loud and vigorous. I haven't done too many
tests yet to see how long I can draw out the streamers, but I can pivot the
terminals 360 degrees each and getting easy (and loud) six inch streamers. The
brush discharge in low light is strong, purplish and violet. Passing a clear
incandescent bulb (on an insulated handle!) between the terminals provokes
really violent plasma displays.

I will try to post pictures of it soon.

Paul Thompson

--- In VanDeGraaffGenerator@yahoogroups.com, Khem Caigan <Khem@...> wrote:
>
> Paul Thompson doth schreibble :
> >
> > The oddest example of interference I've experienced was with a digital
clock/thermometer.
> > When I run my Van de Graaff downstairs in the kitchen, the thermometer,
which lives in
> > an upstairs bathroom, goes nuts, scrambles, reverts to 24 hour time and
centigrade
> > instead of Fahrenheit. This puzzled me until I realized the sensor for the
thermometer
> > hangs out the bathroom window at the end of a long wire. I imagine the wire
acts like
> > an antenna, picks up the waves from the VDG, and conducts them into the
unhappy device.
>
> This is more-or-less the way that radios worked,
> Once Upon a Time :
>
> Spark-Gap Transmitter
>  From Wikipedia, the free encyclopedia
> http://tinyurl.com/rdgm2x
>
> 1921 Spark Gap Transmitter / Ham Radio
> YouTube
> http://tinyurl.com/pnfygw
>
> A 375 Meter/800 KHz Spark Transmitter On The Air
> September, 2006
> Submitted by Ken Beck, WI7B
> http://tinyurl.com/ojsqc3
>
> Cors in Manu Domine,
>
>
> ~ Khem Caigan
> <Khem@...>

Of course, but I was puzzled why the clock, out of all the appliances and
devices in the house, was the only thing affected. I use rabbit ear antennas on
my TV, and the TV wasn't affected. I guess the length of the thermometer sensor
wire was closer to the wavelength of the VDG's sparks?

PBT