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Re: small 4KV transformer, anyone?



Original poster: "resonance" <resonance@xxxxxxxxxxxx>



Using an insulated stand is always a good idea. A person's hair will provide a lot of leakage current, so all a child really needs to do is release his hand from the sphere, then wait 10 sec, and step down. Even with our large 24 inch and 30 inch dia. spheres the child is totally discharged by the time he/she steps down.

Ok --- thanks Terry --- back to Tesla coils!!

Dr. Resonance


-- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, August 28, 2006 4:32 PM
Subject: Re: small 4KV transformer, anyone?


Original poster: coolbluesky <coolbluesky@xxxxxxx>

Hi Dr. R, all...

Although not directly Tesla related, I found an interesting article about Van de Graaff generator safety, and physiological effects of unintended electrical discharges here:

http://www.sserc.org.uk/public/Safety_Messages/safety2.htm

Certainly worth reading if planning a public demonstration. Makes me cringe when I recall certain human "chain" demos at various science museums I've seen.

Safe Zapping, everyone.

Karl

On Aug 28, 2006, at 2:54 PM, Tesla list wrote:

Original poster: "resonance" <resonance@xxxxxxxxxxxx>




The high school VDGRFs were all frictional excited and delivered only 3 uA DC to the sphere. It isn't the charging current that is the problem --- it's the peak current that is delivered by the capacitance of the sphere. Typically 40 Amps off a 14 inch dia. sphere.

We run terminals up to 30 inch dia. on our VDGRF at 750 kV but we use a unique system of insulating the person from ground so he/she doesn't discharge the current directly to ground. A 30 inch sphere charged will deliver peak currents of 85 Amps for 1 usec.

I make and sell belts for VDGRFs and you don't need teflon for the belt material.

You can discuss this with me at the Teslathon.

Dr. Resonance



As they say the only stupid question is the one unasked, but I was wondering what is the largest VDG that could be built and still be considered safe (tho perhaps uncomfortable) to be hit by? I came across 400kV 10uA ones when I was in high school. Is that the "safe" limit (considerig alot of goofball kids around it)? Was thinking of using 1 of those 30" steel ball lawn ornaments I have lying around to make one whenever I can find some suitable 4-6" pullies (aluminum and teflon hard to find), just don't wanna kill myself when I go to do the hair-standing stunt.

Mike
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, August 27, 2006 7:27 PM
Subject: Re: small 4KV transformer, anyone?


Original poster: "resonance" <resonance@xxxxxxxxxxxx>





ED

Just rectify it. That's all you need to spray a VDGRF belt. We use 5 kV, 2 mA xmfrs to spray belts up to 30 inches wide when rectified --- it only takes 200-500 uA with a 30inch wide belt and only 100 uA DC with a 6-8 inch wide belt. See our model HV-750 (750 kV DC 30 uA output) at our website www.resonanceresearch.com.

Dr. Resonance


Original poster: Ed Phillips <evp@xxxxxxxxxxx>

Had trouble downloading the catalog so couldn't find out if those things are used with esternal rectifiers. Any idea? I have a unit which appears identical - picked it up at a swap meet years ago. It was supposed to have come from a Xerox machine. I think with a voltage multiplier it would be neat for charging VDG belts.

Ed