Jacobs ladder.

Simonslimline · Jan 26, 2016

I salvaged a 5KV Tx out of an old microwave and made a Jacobs ladder. I have not been able to get the arc to rise yet unfortunately.

Has anyone made one of these before? and if so what sort of transformer did you use?. I have been looking for neon sign ones but can't seem to find any for sale in the UK.

An odd question perhaps, but it's just a bit of fun really.

Thanks

Marvo · Jan 26, 2016

I made one as an apprentice which was only a few years ago (maybe 35). I used a flyback transformer out of an old TV. If you mess around with that type of tranny be very careful, they will give you a whack large enough to knock you into next week or even the next life.

Simonslimline · Jan 26, 2016

Marvo said:
I made one as an apprentice which was only a few years ago (maybe 35). I used a flyback transformer out of an old TV. If you mess around with that type of tranny be very careful, they will give you a whack large enough to knock you into next week or even the next life.

What KV was it out of interest Mate?

I am sure 5KV is enough for it to work but it does not say what current.

People seem to be using neon sign 10KV 30ma ones and getting good results.

davesparks · Jan 26, 2016

Look in the things to make and do section of bigclive.com he's got a write up on it somewhere.
You can start the arc by adding another small electrode between the two main ones and connecting it via resistors to encourage the arc to start.

I've got a neon sign transformer sitting in the warehouse waiting for me to build one of these

Simonslimline · Jan 26, 2016

davesparks said:
Look in the things to make and do section of bigclive.com he's got a write up on it somewhere.
You can start the arc by adding another small electrode between the two main ones and connecting it via resistors to encourage the arc to start.

I've got a neon sign transformer sitting in the warehouse waiting for me to build one of these

Thanks, i will take a look at that site.

If i get it to work i will post a vid up of it.

Marvo · Jan 26, 2016

I'd take a wild guess at maybe 20KV and maybe more but I'm not 100% sure offhand but it would have been very much dependent on the frequency of the switched DC supply on the primary side. Here's a basic circuit for a flyback.

Simonslimline · Feb 3, 2016

It works a treat. I am going to get some copper pipe and make a twister rather than the arc just rising. I would post a video but not sure how to get it off my camera right now.

Marvo · Feb 3, 2016

I've never heard of the twister, maybe it's a more recent fad but the rising arc between two wires tends to work better if the wires are perfectly straight and the gap at the top is only very slightly larger than the gap at the bottom. We also used to use just single core straight wires, I'm not sure if the twisted wires will affect its performance. They're a bit finniky and need some delicate fine tuning to get a good effect usually.

Simonslimline · Feb 4, 2016

Marvo said:
I've never heard of the twister, maybe it's a more recent fad but the rising arc between two wires tends to work better if the wires are perfectly straight and the gap at the top is only very slightly larger than the gap at the bottom. We also used to use just single core straight wires, I'm not sure if the twisted wires will affect its performance. They're a bit finniky and need some delicate fine tuning to get a good effect usually.

Twister may not of been the correct term to be honest. This is what i want to make.

https://www.youtube.com/watch?v=-AsaGgb5ixo

Simonslimline · Feb 4, 2016

Cant seem to add pics to my other post so here is a couple more.

pennychew · Feb 5, 2016

Simonslimline said:
Cant seem to add pics to my other post so here is a couple more.

View attachment 31394 View attachment 31395

Health and safety would have a field day with that!

Get some of these stuck on it asap and it will be ok..

Simonslimline · Feb 5, 2016

pennychew said:
Health and safety would have a field day with that!

Get some of these stuck on it asap and it will be ok..

View attachment 31410

The only issue with it is it is just not big enough at the moment.

unk:

Simonslimline · Feb 11, 2016

I have a flyback and am wondering how i know which is the primary i am after. I have tested with a multimeter and am getting the same reading across a couple variations. From some videos i have watched i am looking for a reading that is close to one Ohm, or is it different for each flyback? I am also getting a reading of 0.5 ohms between pin 1 and pin 3. Thanks in advance for any help.

Marvo · Feb 12, 2016

It's always fun and games figuring the pinouts on a flyback. Have a squiz at this, 30kV Flyback PSU | GardenBallistics

I'm gonna say this again even though I'm sure you're already aware. Be very careful, a flyback can give you a whack big enough to knock you on your --- or even into the next life if you're really unlucky.

Simonslimline · Feb 12, 2016

Marvo said:
It's always fun and games figuring the pinouts on a flyback. Have a squiz at this, 30kV Flyback PSU | GardenBallistics

I'm gonna say this again even though I'm sure you're already aware. Be very careful, a flyback can give you a whack big enough to knock you on your --- or even into the next life if you're really unlucky.

Thanks Marvo, much appreciated.

Simonslimline · Mar 26, 2016

Got another transformer so paralleled the primaries and the secondaries are in series. Bigger arcs and a wider gap like this. pops the 13amp fuses after a few continuos goes though.

Marvo · Mar 27, 2016

Very nice

...maybe go with a C-curve mcb if your impedance is low enough to still achieve disconnect times or is it the plug fuses that are popping?.

Simonslimline · Mar 27, 2016

Marvo said:
Very nice ...maybe go with a C-curve mcb if your impedance is low enough to still achieve disconnect times or is it the plug fuses that are popping?.

Got them on a plug top at the moment. Can get a couple arcs then the 13 amp 1362 fails. :shades_smile:

Marvo · Mar 27, 2016

Simonslimline said:
Got them on a plug top at the moment. Can get a couple arcs then the 13 amp 1362 fails. :shades_smile:

Lol, I forgot you have 13A socket outlets in the UK, I'm used to the 16A sockets we have here. If you carry on expanding your system you're going to have to install a shower circuit with a 32A commando socket for your experiments

Simonslimline · Mar 27, 2016

Marvo said:
Lol, I forgot you have 13A socket outlets in the UK, I'm used to the 16A sockets we have here. If you carry on expanding your system you're going to have to install a shower circuit with a 32A commando socket for your experiments

Yeah i got a couple of spare ways in the consumer unit. :teeth_smile: