Jacob's Ladder Build

[ryansoh3]

Thanks SL! Maybe I'll pick one up.

Things said they're impossible to destroy, but you said that it's more dangerous than a SSNST, right? Does it have PFC?

Cheers! :beer:

 

[Seoul_lasers]

Thanks SL! Maybe I'll pick one up.

Things said they're impossible to destroy, but you said that it's more dangerous than a SSNST, right? Does it have PFC?

Cheers! :beer:

Yup... judging by the VA rating it's got a pfc (power factor correction) Capacitor inside. This keeps the current and voltage in phase of each other. Non-PFC neons will easily pull much more than their rated current the instant they are turned on. That's wasted power.
~125-130VA... non PFC would be 450VA Yes , they are MUCH MUCH more dangerous than a SSNST because they'll keep delivering current even when they are shorted. They have also been known to overheat in a shorting situation and catch fire. They are potted in tar as well. They have no protection circuit. If that happens to be your hand then expect to get shocked and burned. Treat the output with the utmost respect at all times.
The transformer at the shop is brand new. ^^
You can also parellel the same kind of NST (same current rating and voltage) for more current. I've done up to 6x 12kV 60mA NSTs 3 | 3 dual phase on a 240V outlet in Canada. That was for a large Tesla coil I built.

 

[Things]

Went to visit the cousins and pick up my brother over the weekend, so went to visit Aussie50 (From youtube) and bought a 2nd 15kV 30mA NST off him, similar to my other one.

Put em in parallel for 15kV 60mA, and get some pretty serious ~12cm arcs from it. Almost MOT like at around 900W.

Just need a few more and we're getting serious

 

[ryansoh3]

Wow, looks great!

What would doubling the current from 30mA to 60mA do to the ladder?

Also, how long did it take for an arc to rise from the bottom and break?

Cheers! :beer:

 

[Things]

Increasing the current makes the arc hotter, and also allows it to stretch out further.

Increasing the voltage makes the distance for starting the arc larger, but if you have low current, the arcs will just become sparks - blue/white and noisy, and not work for a jacobs ladder at all.

NST's can't be seriesed most of the time, because a. most of the time their centre tap is grounded, and b. the insulation is already run within a shred of it's strength, so doubling the voltage would most likely just cause an internal arc over.

Time the arc takes varies greatly, they are hugely effected by wind, you can even blow them back down again, but a good arc, from bottom to top can take about 2-3 seconds.

 

[ryansoh3]

Thanks for your reply.

Is your NST solid state or made of coils? I really need to get a better NST for my build.

I think a MOT's voltage is about 2.5KV with a lot of current. I'm guessing it's not suitable for a Jacob's ladder.

Cheers! :beer:

 

[Things]

They're both coils. If it's damn heavy, then you can be certain it's a coil type

MOT's work well for jacobs ladders, EXCEPT, they usually have low duty cycles (Can't run them for too long without overheating), and because they're only 2kv, the gap at the bottom has to be _very_ small to get it to start.

But if you don't mind that, MOT's work great, just be careful, no 2nd chances with them like NST's

 

[ryansoh3]

Aites, thanks for the info.

Will pickup a microwave and take it apart.

I'll update as progress as made, hopefully without killing myself.

Cheers! :beer:

 

[Things]

Hehe, just always unplug it before going near it, and never go near it while it's on and you'll be fine.

I'm uploading a video of it + a few highspeed shots now

Edit: here we go:

 

[Seoul_lasers]

Aites, thanks for the info.

Will pickup a microwave and take it apart.

I'll update as progress as made, hopefully without killing myself.

Cheers! :beer:

Please take great care when working around MOTs. Their output is instantly lethal.
The NSTs are more survivable if you happen to shock yourself by accident. Though it'll be a painful memory. A MOT will deliver +1A at 2000-2500V if you have them non-pfc.

These sites are a good read before doing anything with MOT transformers:

NST and MOT Power for a Tesla Coil
How to: Resonant Microwave Oven Transformer High Voltage Supply.
Home - MOT tesla coil

 

[DashApple]

Nice Jacobs ladder , I made one with 4 MOT's in series for 8Kv @ 600ma ish
under arcing It pulls 20 Amps at 230Volts ( 4.8Kw ) .

loud noise is the Inductive ballast Vibarating alot just off screen .


8kv @ 600ma MOT stack Jacobs ladder - YouTube

 

[Seoul_lasers]

That's a pretty decent arc. Done the 4 pack mot ladder with copper uprights before. It's impressive. I have also done 5 (asymmetrical) 4x mots and one 2500V rated G.E.Potential
transformer was able to pull 3A @ 2500V from this. (rated for 50KVA) Weights 60Kg.

Peak output was somewhere around 11Kv @ 600-700mA. You can pull off this 5 pack with dual phases.
The largest transformer bank I was able to successfully pull off was a 6pack and this requires a major modification of the transformers and lots of Shell dialex teflon based transformer oil.
To do a 6 pack MOT supply all the Transformers needed the filament windings removed and the shunts knocked out.
At this point, running them un ballasted is NOT an option. Also, by removing their shunts the transformers become more efficient and run cooler, also there is a slight increase in output voltage as well.
Ballasting requires a shorted buzzbox arc welder running on a 50A service.