Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper

cheers

Jules

On 29/12/2011 22:35, Jules Richardson wrote:

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper

Astonishingly hard to do because of splashes and other minor details.

If you are serious build a Wimshurst machine instead. There is a
sporting chance of getting that to work if you are any good.

http://en.wikipedia.org/wiki/Wimshurst_machine

Details at the URL may be insufficient. Or even easier a Telsa coil
which through being high frequency AC is a little bit less likely to
kill you.

All usual safety disclaimers apply. These things bite!

Regards,
Martin Brown

Martin Brown wrote:

On 29/12/2011 22:35, Jules Richardson wrote:

anyone here built one?

Astonishingly hard to do because of splashes and other minor details.

This might give a few clues for scale and construction ...

http://youtu.be/RQX8I9ZWtPQ#t=44m03s

If you are serious build a Wimshurst machine instead.

But where're you going to get 7 foot diameter glass discs? :-P

http://www.coe.ufrj.br/~acmq/bigwin.html

In article ,
Jules Richardson writes:

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper

Haven't seen that one before, but I have built another water drop
HV generator way back at school, but I can't remember what it's
called.

IIRC, it worked like this...

You have two tanks of water, one above the other, both insulated
from the environment. A shower head allows the top tank to drain
into the bottom tank, with as fine a droplets as possible. You
apply a high voltage to the top tank (I think we had a 5kV DC
lab power supply for the purpose).

Each droplet leaves the shower head with a fixed charge,
corresponding to 5kV at the self-capacitance of the droplet. When
the first droplet lands in the bottom tank, it will retain its 5kV
as we'll assume there are no charge losses and the capacitance of
the droplet doesn't change (both false assumptions, but not badly
enough to stop it working). The next droplet lands and merges with
the first drop. Now the charge is doubled, but the capacitance of
the combined drop only increases a little, so to preserve the
charge, the voltage increases significantly. As more charged
droplets are added to the lower tank, the voltage of it increases
markedly, and it will arc across to ground or the top tank.

Now, the big problem with this is that by the time you've got the
water part working, the bench, floor, and aparatus will be swimming
in copious split water, and nothing is an insulator anymore, so it
doesn't work. Somewhere near my school, Bic Biros used to be made,
and we got a sack of reject brio tip balls for experimenting with.
Using these instead of water was much more successful (you can
clear up spillage without leaving surfaces conducting). ISTR we
were easily getting 100kV sparks off the bottom tank. Biro balls
don't pack as well as water droplets which reduces the voltage
rising potential collecting in the bottom tank, but on the other
hand, they are much smaller which means more "droplets" and hence
more charge can be carried between the two tanks (I think).

Anyway, hope I remembered all that correctly...

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Thu, 29 Dec 2011 23:44:52 +0000, Andrew Gabriel wrote:
Haven't seen that one before, but I have built another water drop HV
generator way back at school, but I can't remember what it's called.

IIRC, it worked like this...

Yes, I've seen that mentioned somewhere in the past, albeit IIRC just
termed a "half kelvin generator" - perhaps it doesn't have a 'proper'
name.

In message , Jules Richardson
wrote

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper


In the same spirit
http://www.bigclive.com/makendo.htm

Instructions for blowing up things, making ozone, making power saving
devices, making a USB turd, making a fuel magnet, making a Jacob's
ladder etc.

--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk

On 29/12/2011 23:23, Andy Burns wrote:
Martin Brown wrote:

On 29/12/2011 22:35, Jules Richardson wrote:

anyone here built one?

Astonishingly hard to do because of splashes and other minor details.

This might give a few clues for scale and construction ...

http://youtu.be/RQX8I9ZWtPQ#t=44m03s

Now there is a man who fits all the stereotypes of what a scientist
should look and sound like!


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

When young I had a go at vanda graph, windshurst etc static devices. Not
that hard to make but lethal in action. Also prone to falling to bits, but
then that was probably my fault!

Lets just say that the friction was not only in the machines, but with my
Mother whose old bits and pieces I tended to press into service for making
them.
I'd never heard of this device before.. interesting.
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Martin Brown" wrote in message
...
On 29/12/2011 22:35, Jules Richardson wrote:

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper

Astonishingly hard to do because of splashes and other minor details.

If you are serious build a Wimshurst machine instead. There is a sporting
chance of getting that to work if you are any good.

http://en.wikipedia.org/wiki/Wimshurst_machine

Details at the URL may be insufficient. Or even easier a Telsa coil which
through being high frequency AC is a little bit less likely to kill you.

All usual safety disclaimers apply. These things bite!

Regards,
Martin Brown

It would seem to be very over sized.. its the trueness of said discs and
their structural integrity which would be hard to do.
Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Andy Burns" wrote in message
news
Martin Brown wrote:

On 29/12/2011 22:35, Jules Richardson wrote:

anyone here built one?

Astonishingly hard to do because of splashes and other minor details.

This might give a few clues for scale and construction ...

http://youtu.be/RQX8I9ZWtPQ#t=44m03s

If you are serious build a Wimshurst machine instead.

But where're you going to get 7 foot diameter glass discs? :-P

http://www.coe.ufrj.br/~acmq/bigwin.html

Brian Gaff wrote:

It would seem to be very over sized.. its the trueness of said discs and
their structural integrity which would be hard to do.
Brian


Aren't old records (particularly 78's) a favoured source for such things?

--
Tim Watts

On 30/12/2011 09:01, Tim Watts wrote:
Brian Gaff wrote:

It would seem to be very over sized.. its the trueness of said discs and
their structural integrity which would be hard to do.
Brian


Aren't old records (particularly 78's) a favoured source for such things?

Old shellac records are ideal for rigidity and insulation properties.


Regards,
Martin Brown

On 30/12/2011 09:21, Martin Brown wrote:

Old shellac records are ideal for rigidity and insulation properties.


We had a commercially built one at school. The discs were about LP size
- I suspect slightly more than a 78, though I could be wrong after all
this time.

I connected it once to a Leyden Jar made from a Kilner jar. I thought
for a while that I had a leak somewhere, as nothing happened. It turned
out to be just that it was taking a while to build up the charge...
quite a nice bang.

Andy

On Thu, 29 Dec 2011 22:35:18 +0000, Jules Richardson wrote:

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper



I've never built one, but from the look of the ones on the web probably
not very critical. The droplets are just a means of transferring the
charge from the ring to the bucket. The secret appears to be to get a
very narrow stream of water so that the charge can split it into charged
droplets easily. One site suggests capping the pipes and drilling a 1.5mm
hole through the cap for the flow.

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info
Filtering everything posted from googlegroups to kill spam.

"Martin Brown" wrote in message
...
On 29/12/2011 22:35, Jules Richardson wrote:

Most of the inhabitants of this group are bonkers, so... anyone here
built one? Anyone happen to know how critical it is to balance the
flow of water drops through the conducting rings?

For the curious: http://en.wikipedia.org/wiki/Kelvin_water_dropper

Astonishingly hard to do because of splashes and other minor details.

If you are serious build a Wimshurst machine instead. There is a sporting
chance of getting that to work if you are any good.

http://en.wikipedia.org/wiki/Wimshurst_machine



aren't van-de-graf generators the easiest way to produce static charge ?

On Thu, 29 Dec 2011 23:23:42 +0000, Andy Burns wrote:
If you are serious build a Wimshurst machine instead.

But where're you going to get 7 foot diameter glass discs? :-P

http://www.coe.ufrj.br/~acmq/bigwin.html

Impressive :-)

I think a lot of the modern table-top ones use acrylic sheet rather than
glass, which would be a much easier material to work with. Bit pricey if
it's just for giggles, though - something around 2 feet in diameter comes
to about $160 here (around 100 quid?) for both wheels, assuming a 1/2"
thickness.

I suppose that typically the metal sectors on the wheels only occupy the
outer 50% of the disc surface - given that acrylic's normally sold in
sheets there's a lot of waste in cutting discs from it, but it might be
possible to build up a laminated disc (with spokes connecting to the
hub), trading cost for assembly time. Of course then the question's what
to use to glue everything together without sacrificing insulation :-)

*maybe* it's possible to make one out of wood too if it's very heavily
varnished, but I suspect that it wouldn't perform nearly as well.

cheers

Jules

Jules Richardson wrote:

On Thu, 29 Dec 2011 23:23:42 +0000, Andy Burns wrote:

http://www.coe.ufrj.br/~acmq/bigwin.html

I think a lot of the modern table-top ones use acrylic sheet rather than
glass, which would be a much easier material to work with. Bit pricey if
it's just for giggles, though

I did have a quick google, 10mm thick 3mx2m sheet was over £1k

On 30/12/2011 19:08, Andy Burns wrote:
Jules Richardson wrote:

On Thu, 29 Dec 2011 23:23:42 +0000, Andy Burns wrote:

http://www.coe.ufrj.br/~acmq/bigwin.html

I think a lot of the modern table-top ones use acrylic sheet rather than
glass, which would be a much easier material to work with. Bit pricey if
it's just for giggles, though

I did have a quick google, 10mm thick 3mx2m sheet was over £1k


Well, it doesn't have to be 5ft.

A couple of these ought to do:

http://www.btowstore.com/epages/Stor...ducts/10500500

AKA

http://tinyurl.com/7vkhfo6

Andy