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Jacobs ladder

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Jakes
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Post Number: 34
Registered: 09-2005

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Posted on Sunday, 23 July, 2006 - 07:25 pm:   Edit Post Delete Post Print Post

can any one help me to build a jacobs ladder and can it work from a 2kv transformer
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Paul_goodson
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Post Number: 484
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Posted on Sunday, 23 July, 2006 - 07:58 pm:   Edit Post Delete Post Print Post

did you look here

http://www.google.com/search?hl=en&q=jacobs+ladder+
Paul
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Micro82
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Post Number: 62
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Posted on Sunday, 23 July, 2006 - 08:11 pm:   Edit Post Delete Post Print Post

Hi there,

It will all depend on what type of transformer you are planning on using.

The best would be a neon sign transformer (Mainly due to the build in current limiting).

With this and a couple of length of copper refrigeration tubing you should be able to get at least a simple one going.

Have a look at the upload this is a small video from one we (Myself & Tvmender) was experimenting with a few months back.

The transformer we used was a 3Kv @ 36mA (Approx 36Watts).

As you can see from the upload we managed to get a pretty decent Jacobs ladder running.

Hope this helps.

Regards
Pete
Pete@customsoft.karoo.co.uk

P.S Experimenting with such HIGH voltages is NOT recommended to people without prior knowledge of the safety implications involved.
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Jakes
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Post Number: 35
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Posted on Sunday, 23 July, 2006 - 08:24 pm:   Edit Post Delete Post Print Post

can you also use a microwave transformer?
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Mikehibbett
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Post Number: 503
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Posted on Sunday, 23 July, 2006 - 08:45 pm:   Edit Post Delete Post Print Post

Seems like a candidate subject for this:

http://www.darwinawards.com/

:o)
-----
www.drivesentinel.co.uk - Home build GPS Speed Camera Detectors
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Jakes
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Post Number: 36
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Posted on Sunday, 23 July, 2006 - 09:08 pm:   Edit Post Delete Post Print Post

can you use a 240v/2000v microwave transformer
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Tvmender
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Post Number: 63
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Posted on Sunday, 23 July, 2006 - 09:13 pm:   Edit Post Delete Post Print Post

Hi Jakes,

You can use a MOT but it is not advised as they dont have current limiting, you would have to engineer in the current limiting with a choke or alike.

I would agree with Micro82, a Neon Sign Transformer I think is best and "safer".

The transformer we used was a small 360w type which you can sometimes pick up on e-bay fairly cheap. We bothered some workmen at a nightclub refurb for ours.

The one we used was great fun and would quench at about 2" which was pretty impressive. I am shortly going to buy a 10Kv 50mA transformer for my Tesla coil but I think a small Jacobs ladder to test it is called for!

We recently attended a Teslathon in Derby where a Jacobs ladder powered from a "pole pig" (distribution transformer, like those on a pole in a field!!!) now THAT was inpressive!

Good luck!

- Tvmender
"Nothing unreal exists"
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Atferrari
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Posted on Sunday, 23 July, 2006 - 11:18 pm:   Edit Post Delete Post Print Post

Hola Pete,

What upload are you talking about?

Gracias
Agustín Tomás - Buenos Aires - Argentina
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Obiwan
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Posted on Sunday, 23 July, 2006 - 11:19 pm:   Edit Post Delete Post Print Post

Ditto the neon stuff.

This is another one of those projects where you can do a whole lot of stuff, but it's better to just keep it simple.

if you spend a little time looking around, you can find neon sign transformers at good prices, used, that sort of thing, old signs....

But don't use something like a rusted out one!

Just do it the easy way, safer too.


Tvmender, I'd LOVE to see a picture of that thing! Did you by chance get a photo of it?
Do Not Hit The Fly That Lands On The Tigers Head.
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Tvmender
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Post Number: 64
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Posted on Sunday, 23 July, 2006 - 11:34 pm:   Edit Post Delete Post Print Post

Hi Obiwan,

I do have one photo but the thing was so quick I took the photo and it had started the arc over again so its only at the bottom of the ladder. I do have some fanstastic photos of a BIG coil powered by the transformer at the Nottingham Gaussfest and at the Derby teslathon.

The poles must have been 3 feet tall and about 6" or so wide at the top to get a nice white hot arc. The sound was amazing (BRRRRAP) and the arc snaked around above the ladder for a few seconds before quenching! (Have you seen the video of the 500kv substation arc on electricstuff.co.uk? it was sort of a minature version of that! If not I will get the link for you.)

I only had my digital camera a few weeks at this point and didnt realise (didnt read the instructions) that it did video! doh!

I can mail you some of the photos if you require?

You can mail me at Sam@electronics.karoo.co.uk and I will forward some if required.

I hope to have my Tesla Coil going shortly, all that remains is to build the tank cap and safety gap and oh yes, fork out for the NST!



Good luck,

- Tvmender (Sam)
"Nothing unreal exists"
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Ant
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Post Number: 31
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Posted on Sunday, 23 July, 2006 - 11:39 pm:   Edit Post Delete Post Print Post

Hello all,

SAFETY NOTE: I _think_that microwave transformers may not have isolated secondaries!

Regards Ant
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Micro82
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Post Number: 63
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Posted on Sunday, 23 July, 2006 - 11:59 pm:   Edit Post Delete Post Print Post

Hi All,

Sorry about the clips unfortunately I was unable to upload them on here s they are too big.

I have now uploaded them onto my server the address is below,

Enjoy!!!!

http://87.102.38.104/JLadder/
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Dean_huster
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Post Number: 161
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Posted on Monday, 24 July, 2006 - 12:57 pm:   Edit Post Delete Post Print Post

Just don't forget that the adjective being used here for luminous tube transformers is SAFER and not SAFE. 15KV can reach out and grab you and 30mA can hold you tightly in its arms, so don't think you're working with the equivalent of a Van de Graf generator here! We don't want to see any obits posted on the forum.

Dean
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Zeitghost
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Post Number: 294
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Posted on Monday, 24 July, 2006 - 04:04 pm:   Edit Post Delete Post Print Post

Safer?

Not safer at all!

Deadly.

15kV at 30mA is totally deadly.
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Tvmender
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Post Number: 66
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Posted on Monday, 24 July, 2006 - 06:02 pm:   Edit Post Delete Post Print Post

Hi all,

I honestly didnt think I needed to mention the safety aspect, I am sure it is completely obvious that electricity especially in this situation is potentially lethal.

The post was intended to inform the poster that using a current limited device is SAFER and it wasnt my intention to sporn a mass of safety aware threads.

"safer" I said not SAFE

Sigh,

Tvmender
"Nothing unreal exists"
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Zeitghost
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Post Number: 296
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Posted on Monday, 24 July, 2006 - 07:11 pm:   Edit Post Delete Post Print Post

It's obvious to you, me and the gatepost, TVmender, but probably not to the sort that tries to dry the poodle in the microwave... :o)
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Tvmender
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Post Number: 67
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Posted on Monday, 24 July, 2006 - 10:42 pm:   Edit Post Delete Post Print Post

Hi Zeitghost,

I am sure drying the poodle in the microwave would give it an even funkier hair-do! I dont know, the length these posh dog owners will go to for poodle perfection!

It is a good idea to mention though that the jacobs ladder primary power side needs to be fool proof. Its easy to forget the power is on when the arc quenches and doesnt restart, I found holding the plug for the NST in one hand and then adjusting using the other was a good idea.

The link to the Jacobs ladder site at the top of the threads mentions an aptly named "dead mans switch" which will automatically cut the power when released, good idea.

Good luck,

-Tvmender.
"Nothing unreal exists"
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Joe
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Post Number: 158
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Posted on Tuesday, 25 July, 2006 - 07:54 am:   Edit Post Delete Post Print Post

"It is a good idea to mention though that the jacobs ladder primary power side needs to be fool proof."

The problem with trying to design something fool proof, is underestimating the ingenuity of complete fools.

The number of times I've proved that saying to be correct... <sigh>
Do one thing each day that scares you – work here !
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Labathome
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Posted on Tuesday, 25 July, 2006 - 08:05 am:   Edit Post Delete Post Print Post

See also "Sparks 'n Arcs" in Elektor February 2006 for a small Jacob's Ladder with due attention given to safety.
Not allowed to post deep link here, sorry.


Richard
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Jakes
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Post Number: 37
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Posted on Tuesday, 25 July, 2006 - 07:34 pm:   Edit Post Delete Post Print Post

hi Richard can you mail it to me please springboks11@yahoo.com
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Labathome
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Posted on Monday, 31 July, 2006 - 10:33 am:   Edit Post Delete Post Print Post

Hi Jakes,

the article can be purchased online from the Elektor website.
Sorry, arw sez no deep linking allowed to competitor publications.

regards
Richard
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Poriet
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Post Number: 72
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Posted on Wednesday, 02 August, 2006 - 05:45 pm:   Edit Post Delete Post Print Post

The problem with stuff like this is that, while it may be foolproof, it isn't neccessarily idiot
proof.
BTW, the dog-in-the-microwave story is almost certainly a myth. Some years ago, a young lawyer I knew went to the US on some business and he
searched ( this was before the internet, mind you ) for the case. He couldn't find any reference to it.
One last thing, where on Earth can you get used neon-sign transformers?
P.
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Micro82
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Posted on Wednesday, 02 August, 2006 - 06:18 pm:   Edit Post Delete Post Print Post

Sourcing used Neon Sign Transformers isn't that hard these days.

With the likes of Ebay they are widely available. There are also a number of company’s here in the Uk where you can buy then from as NEW or USED.

Pete
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Poriet
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Posted on Thursday, 03 August, 2006 - 10:50 am:   Edit Post Delete Post Print Post

I've just had a thought.
Some say that the neon sign transformer is safe-ish because it's current limited to 30mA, but one CZ poster said that 15KV @ 30mA is deadly.

The answer, I think, is that they're both right.
Sort of. A current of 20mA through you is very nasty ( although to be really deadly it helps if the current path is from hand to hand and therefore directly across the heart ) A 30mA flow is probably fatal.
The difficulty is actually getting that sort of current to flow across a person, because your skin resistance and the resistance of your shoes is high. Of course, 15KV would have no problem, but then the internal impedance of the supply is very high as well, so, as current starts to flow, the voltage drops like a stone and all you get is a nasty reminder not to meddle in things you dont understand.
It isn't so much the voltage that matters, but the 'stiffness' of the supply. That's why the mains is so deadly, and most other forms of high voltage aren't. Except, fo course, the microwave transformer, which is SO lethal I wont mess with them.
Regards
P.
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Zeitghost
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Posted on Thursday, 03 August, 2006 - 11:36 am:   Edit Post Delete Post Print Post

Believe me, 15kV at 30mA is stiff...
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Tvmender
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Posted on Thursday, 03 August, 2006 - 08:41 pm:   Edit Post Delete Post Print Post

Hi all,

I think I need to elaborate on "safer" and "foolproof"....

When we mention "safer" we are not refering to wether a shock off the NST is going to kill you or not, it almost certainly will.

"Safer" as we refer to means that you are unlikely to draw so much current from your HV source that things are going to burn or explode and your supply be damaged. You are stressing the NST with your ladder but I am sure it will survive longer than any other transformer.

The short circuit rating of an NST is what it says.. the transformer will supply 30mA under normal load and 50mA when shorted.

At this voltage things get very very nasty, even a few milliamps will kill you even at mains potential and/or leave you with substantial burns.

NSTs are now limited to 10,000v in the UK now because 15,000 seemed a little too dangerous?!?!?

By no means is this SAFE. You must have the experience to know what is likely to happen.

"Foolproof" is probably a badly chosen term by myself. What I mean by foolproof is your basic good working practice when HV is involved.

Holding the plug to the NST in your hand as you make adjustments to the ladder, not working alone and making sure the person you are working with knows CPR, how to isolate the supply and having something like a push to make button on the primary of the NST which will not allow you to get close to the ladder without having to let go of the button.

Another good idea is to encapsulate the ladder in a ventilated acrylic tube so brushing against it is harder. Use HV cable used in neon signs for your connection leads. Is is easy to approach your ladder is the arc quences and you forget that it is plugged in. Clear the workbench of clutter, stray wires in contact with the ladder are baaad!

Joe was right, nothing is foolproof. Nothing is an insulator, everything conducts eventually.

The ladder will produce nasty gasses like 03 and UV light which could cause arc eye. I could go on and on but as I said before I didnt want to sporn a huge list of safety related articles.

In the Tesla Coil ring there is a discussion about wether being struck by a streamer from a coil is safe or not. Some people say it is because its more high frequency than high voltage and the so called "skin effect" stops you being injured or killed...rubbish!! the high frequency and high voltage cause internal burns and scarring which isnt felt when it happens. If you catch the coil at the wrong time you can actually become connected to the mains!

Anyone who has seen coils in action will know that you naturally dont want to get close.

High voltage is fun to experiment with but if you are silly, careless and negligent then it will put you in the ground, no probs.

I suggest doing some research on the web is a good idea and even visiting a local Teslathon for info. Mikes electric stuff is a good site to have a look at www.electricstuff.co.uk

I really dont want to go on, I am sure we all get the idea now.

Good luck and safe experimenting.

-Tvmender
"Nothing unreal exists"
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G6osv
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Posted on Friday, 04 August, 2006 - 10:39 pm:   Edit Post Delete Post Print Post

I remember back when I was a tv engineer drawing an arc from the top-cap of a line output valve didnt hurt at all but it did burn a hole in my finger,A good source of HV is the guts from the Plasma ball toys its rf so relatiely safe but not a lot of umph in them.
Ian
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Obiwan
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Posted on Sunday, 06 August, 2006 - 03:32 am:   Edit Post Delete Post Print Post

No such thing as fool proof. Because sure enough some fool will come along and make a liar out of you.
I saw those pictures, man, I wouldn't be in the same ROOM with that thing!!!!

That thing was arcing out to the celing tiles! Ya'll could set the building on fire!

But DANG! it looks cool!
Do Not Hit The Fly That Lands On The Tigers Head.
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Tvmender
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Posted on Sunday, 06 August, 2006 - 05:24 pm:   Edit Post Delete Post Print Post

Hi Obiwan,

Yes it was awesome to watch! we actually did have to stop because of the arcing to the celing, there was some earthed poles stood around the coil but I think the celing was closer. The noise was painfull and you could feel the vibration from the noise through the floor.

That coil was one of a pair! at the later Teslathon in Derby its brother was brought out to make the 12" connected UK arc record..and it did it easily! Myself and Micro82 were backed into a really poorly chosen corner when these things were running. I think they are capable of about 5kw each. My digital camera went loopy at one point so I decided to move a little further away! :P

I am hoping that Micro82 will be able to put all the photos on his server so I can link to them from here.

The output from an LOPT transformer from a TV is a good place to start if you are building a Marx generator, I have seen several designs. They are only capable (I say only, lol) of around 1-3mA. I have also had a whack of one of them while I had a scope attached to my PC monitor and my then girlfriend startled me by coming into the room without me noticing.

It was more of a burn hole than a shock but it did make me call her a few carefully chosen names!

Those plasma balls are cheap enough to pull to bits.

Good luck,

- Tvmender
"Nothing unreal exists"
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Steerpike
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Posted on Sunday, 06 August, 2006 - 10:51 pm:   Edit Post Delete Post Print Post


quote:

BTW, the dog-in-the-microwave story is almost certainly a myth




maybe that one is, but this is true enough:

"http://www.news24.com/News24/South_Africa/News/0,,2-7-1442_1707234,00.html"

It makes me wish for the days of Colonialist Opression.
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Obiwan
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Posted on Monday, 07 August, 2006 - 12:44 am:   Edit Post Delete Post Print Post

I KNOW you can't dry a dog in a microwave. Let's just say I know somebody that put a mouse in one a long time ago. And the mouse lasted maybe 50 milliseconds before it was dead.

It just fries their little brains.

I'll bet you can find something about it on www.snopes.com (the dog, not the mouse)
Do Not Hit The Fly That Lands On The Tigers Head.

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