Vande-graph generator question

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dacflyer
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Vande-graph generator question

Post by dacflyer » Wed Jun 26, 2002 10:54 am

is it a must that the HV going to the belt of this machine, must be DC ?<p>and if so, where can i find such HV rectifiers ?<p>i am about 1/2 built in mine,,and i will be using a 15kv / 30ma transformer
where could i find such rectifiers ,, new / used

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Re: Vande-graph generator question

Post by bodgy » Wed Jun 26, 2002 5:39 pm

TV Line Output (LOPT) coils run at 15-25KV -it'll be the lump of plastic lurking near the neck of the tube with the big thick lead coming out of it.<p>Microwave transformers are a possibility (Big CAP near so discharge first) <p>You could also make one see the thread on fence/people zappers earlier this year!<p>bodgy
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dacflyer
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Re: Vande-graph generator question

Post by dacflyer » Thu Jun 27, 2002 12:35 pm

thanx bodgy , i have looked at flyback transformers in tv set,, but the dioads are inside the transformer,,<p>also microwave dioads are too small to handle 15kv,,<p>and the zappers are no good either,,<p>maybe i can series the microwave dioads..but i must find out how much current they can take

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Re: Vande-graph generator question

Post by cow_rancher » Thu Jun 27, 2002 1:17 pm

I know when I built high voltage stuff, including votage doublers and triplers I just used 1000 volt 1N4007's in series, worked fine.<p>Here are some rated at 6,000 volts @ $0.50 each<p>All Electonics<p>What are you guys building?<p>John<p>[ June 27, 2002: Message edited by: cow_rancher ]</p>

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Chris Smith
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Re: Vande-graph generator question

Post by Chris Smith » Thu Jun 27, 2002 3:26 pm

Try Merrideth Instruments ...AZ <p>They used to sell 25kv diodes for 75 cents each a few years back?

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Re: Vande-graph generator question

Post by HomeBrew » Fri Jun 28, 2002 2:08 am

Never heard of TV LINE OUTPUT coils on a pic tube. Must be something new. :eek:

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Re: Vande-graph generator question

Post by bodgy » Fri Jun 28, 2002 7:08 am

Well you have now cos I say so.<p>OR<p>Well I sort of had two trains of thought going and at my age that is just begging for disaster. I had written deflection coils realised my mind was not on the job and only half changed my twittering.<p>Look I just spent two days trying to work out why a program couldn't tell the time - only to find out it was me .<p>Remember 40minutes plus 45 minutes = *.25 mins NOT 20 and to make matters worse I had actually counted it on my watch face I had pulled that code apart som many times--- :confused: <p>bodgy
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Re: Vande-graph generator question

Post by Edd » Fri Jun 28, 2002 6:55 pm

Dacflyer:
A question on Ur VandeGraff generator...is there a change from the norm on your units construction? As I initially read your post
and the ref to the hefty 15kv @30 ma (D E A D L Y)[Probably a neon sign transformer...right?] I was thinking of a supply for a Tesla coil 'til U mentioned the belt ,so , no Tesla...nor Wimhurst. The conventional Vande Graff being an electrostatic self generating unit with its " flying belt" and a low end comb assembly in micro-proximity of the bottom of the belt and a top collector comb also micro- spaced and connected to the top sphere/globe where the static charge collected from the belt is accumulated. Overall, making it a self generating
electrostatic DC unit, with no external HV power injection required. Wherein is your design variance from this norm?
Waaay back in the days when I built my unit , no way could I come up with a rubber belt so my dad suggested a belt made from plastic car seat
material. When one would forget and slide across the seat and touch the metal door handle you were in for getting a painful 3/16 in spark/
shock. It worked out great on the generator, possibly better than the usual rubber belt, with 9 inch sparks available from a rather small unit.
HOMEBREW:
Aus,NZ or UK's. .[LOPT] = US [ Horizontal output transformer] or ["flyback" transformer] or lately [ IHVT] (Integrated Hi Voltage Tranfo)
Don't know if their LOP "coils" cud assuredly be referring to our deflection yoke...Bodgy???
unless you're still cracking code.
Cow_rancher :
On your referred site. Did you happen to notice the DO package that some "clerical" person opted to show for illustration.....no 6kv at that spacing/packaging. <p>73's de Edd

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dacflyer
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Re: Vande-graph generator question

Post by dacflyer » Fri Jun 28, 2002 9:45 pm

i seen at 3 different museums that they used a
HV DC supply to charge the belt,, maybe theres 2 different ways to make the charge...?i am wanting to use the inner circle cut out of a auto innertube,, hoping that may work,,,
always looking for input...<p>also looking for a complete diagram of a whimhurst. i have one here, but i belive its incomplete...<p>thanx all

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Re: Vande-graph generator question

Post by HomeBrew » Sat Jun 29, 2002 12:20 am

:) I remember the old Edmund Scientific catalog listing those generators and they also had a device to help enhance the charge on the belt. Some generators have them and some do not, but i'm not sure just what type of device they use. I would suspect it would be a source of just a few thousand volts DC at a few mills. You don't really need a super high voltage ,since the charges accumulate at the top of the generator and will build over time.

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dacflyer
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Re: Vande-graph generator question

Post by dacflyer » Mon Jul 15, 2002 9:17 pm

hey i found something to work,,, microwave dioads !
125MA @ 25kv !<p>should have thought of that earlier..lol i thought they were less than that,, but not so... thanx a lot guys...

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