Author Topic: Radial Dirod  (Read 16039 times)

Offline DavesWimshurst

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Radial Dirod
« on: May 17, 2009, 02:27:55 PM »
Hi all,
Bluechip reminded me of my dirod I built about 10 years ago.


a little video


I used to leave it set up on my kitchen table.  One day I had an overly sensitive carbon monoxide detector go off.  I called what I thought would be the non emergency fire department number to check it out.   Minutes later a fire engine and a couple of police cars pulled up in front of my house. After determining there was no real danger one of the police officers looking at the dirod asked "What's that? Q bomb?!"  I explained what it really was and gave a demo of it in action.  It had capacitors attached giving it about a 3 or 4 inch spark.  The police woman said  "We could have used that on tha guy we arrested last Thursday!"  Fortunately everyone laughed.

Dave
 

Offline Bernd

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Re: Radial Dirod
« Reply #1 on: May 17, 2009, 02:31:21 PM »
Dave that looks like a project that needs to be writte up here.  :poke:

Bernd
You can't fix "STUPID".

Offline sbwhart

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Re: Radial Dirod
« Reply #2 on: May 17, 2009, 03:16:37 PM »
Is it what we call a vandograph  :scratch:
 :zap:

Stew

A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline raynerd

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Re: Radial Dirod
« Reply #3 on: May 17, 2009, 04:50:37 PM »
Hey that looks fantastic - have you got any more details about exactly what this is and how it works? I teach science and something like that would look excellent on the side of my lab!! I presume it works in a similar way to the Vandergraph - which we do have and is a LOT of fun!!?

Offline Bluechip

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Re: Radial Dirod
« Reply #4 on: May 17, 2009, 05:23:40 PM »
Hi Folks

You need this ..

http://www.amazon.co.uk/s/ref=nb_ss_w_h_?url=search-alias%3Daps&field-keywords=a+d+moore+electrostatic&x=12&y=12

It's all in there, and a whole lot of other delights of HV electrostatics


Dave
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline Divided he ad

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Re: Radial Dirod
« Reply #5 on: May 17, 2009, 05:29:19 PM »
It looks like a powered Wimshurst macine?

A Vandograph generator is that big spark producing chrome dome on my Harrogate 2009 video  :thumbup: 

The Wimshurst machine is the one on the same video that produces the little sparks and has the dancing foil ball on it.


Still these things in all their guises are cool to watch ( but some are also potentially dangerous I think?) I have thought many times about making one  :dremel:



A topic on such a build would be very, very interesting Dave  :poke:   :thumbup:



Ralph.
I know what I know and need to know more!!!

Offline DavesWimshurst

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Re: Radial Dirod
« Reply #6 on: May 17, 2009, 05:45:59 PM »
Bernd,
The machine was built over 10 years ago using the plans in the book "Electrostatics" by A. D. Moore.  Perhaps a few pictures and hints that I can remember will be useful. 
The hub was made from 3/4 inch acrylic and the rods are from 3/8 inch aluminum.  Shallow grooves were turned near the hub end of each rod to help anchor them in the hub using epoxy.  Vent holes were drilled to allow air and excess glue to escape.

I made the frame from polycarbonate because I had some from another project. Stainless screws were used at all joints.
Some more pics:

Charge collectors


Inductors


The machine needs conductive brushes,  I used material from static protection bags used for sensitive electronic devices years ago.   These are the kind with a black opaque coating, never throw anything useful away!.  I'm not sure if the more modern film coated plastic would work.  Wire brushes could work but might scratch the parts.

Stew
Van de graaff generator


home made one


15 inch dome with 12 inch ruler

The copper band was formed in three sections using soft hammers to beat the annealed copper sheet into a spherical aluminum form.  Much work!  The copper was from 4 inch pipe purchased from a scrap yard before the price of copper spiked.  The stainless bowls had to be hand worked because they are so thin.  This project is on hold for the moment awaiting ambition.
Dave



Offline Darren

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Re: Radial Dirod
« Reply #7 on: May 17, 2009, 06:06:49 PM »
Is it what we call a vandograph  :scratch:
 :zap:

Stew



Thanks for that Stew, those where my thoughts but I wasn't entirely sure it was the same thing  :clap:
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Offline Bernd

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Re: Radial Dirod
« Reply #8 on: May 17, 2009, 06:59:27 PM »
Dave,

Thanks for the extra pictures. Very much appreciated.

Very interesting machine. Never seen one like that.

Bernd
You can't fix "STUPID".

Offline sbwhart

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Re: Radial Dirod
« Reply #9 on: May 18, 2009, 12:50:46 AM »
Dave thanks for showing pics very interesting and ingenious
 :mmr:

Stew

A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline raynerd

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Re: Radial Dirod
« Reply #10 on: May 18, 2009, 01:49:48 AM »
thanks for all the info! - it is my next project after Kelvins Generator!!

Offline Brass_Machine

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Re: Radial Dirod
« Reply #11 on: May 18, 2009, 09:42:40 AM »
That's very cool. I think I want to build one!

Eric
Science is fun.

We're all mad here. I'm mad. You're mad.

Offline websterz

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Re: Radial Dirod
« Reply #12 on: May 20, 2009, 09:57:39 PM »
I would like to build a Tesla coil with a motion sensor. We have a lot of cats in the neighborhood... :zap:
"In the 60's, people took acid to make the world weird.  Now the world is weird and people take Prozac to make it normal."
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