Tesla Coil Build Thread

[Down with Umbrella]

Modification: 2.something or other.

New since I have posted pictures last I have installed a 4.5 X 18in Aluminum spun toroid, done a bit of tuning and reduced my wire gauge on my tuning clamp from a stiff 4awg to a flexible 6 awg.
also I had to lower my strike ring when I put the new toroid on!






video! here is the latest. I am still working through some tuning issues im getting some corona at the very top of the secondary but not the frequent breakouts I was getting before.

With this top load I had to move the tap point from around turn 8.5 to around 9.75. Strange, @ 8.5 there was a violent discharge from the top of the secondary to the strike ring. I lowered the top load, and moved the tap point and The discharge from the secondary stopped. Also a break out point on top of the toroid helped too but after further tuning I was able to take that off.

I actually have mixed thoughts on this new spun toroid. I like it but the one I built was less perfect and offered more break out points adding a different effect on streamers. hmm.

 

[Polonium210]

Very nice DWU!! I like the new toroid. Is that an Eastern Voltage toroid?

Also, in the video I noticed some racing sparks on your secondary. Are these causing any damage or carbon tracking?

 

[Down with Umbrella]

Thank you, I actually got it from amazing1.com. Strangly it arrived in one day because it shipped from my neighboring state NH.

Yes that racing is causing carbon tracks, I added a couple layers polyurethane and adjusted the coupling but it's still happening occasionally. Ehhh. I need to build a new secondary with another inch of winding or reduce the amount of turns on my primary.

 

[Sigurthr]

Very nice update, DWU!

With this top load I had to move the tap point from around turn 8.5 to around 9.75. Strange, @ 8.5 there was a violent discharge from the top of the secondary to the strike ring.

What exactly do you mean by "top of the secondary" do you mean the last turn of the coil or from topload underside? If the latter it means you were at tuning maxima (optimal point), if the former it means you were at bad spot.

SG sounds good btw!

 

[Polonium210]

To me the top load seems a bit high.

I believe the top load not only serves as the C in the secondary LC circuit but also to shield the top of the secondary from trying to breakout.

Someone correct me if I'm wrong but I would place the bottom of the toroid level with the last turn on the secondary.

 

[Sigurthr]

To me the top load seems a bit high.

I believe the top load not only serves as the C in the secondary LC circuit but also to shield the top of the secondary from trying to breakout.

Someone correct me if I'm wrong but I would place the bottom of the toroid level with the last turn on the secondary.

Nope, you're totally correct there. The torus shape creates an e-field shape that effectively pushes down on the coil's e-field, suppressing any breakout in its vicinity. You can see good example of this in videos of QCW coils, the center spike breakout point streamers curve along a trajectory that matches the curvature of the torus.

 

[Down with Umbrella]

The corona is building up on the top turn of the secondary not the bottom of the top load.
As it currently sits the toroid is 2 7/8" above the last turn on the secondary. I set this parameter by reading HVtesla.com. (Set the top load .8 the minor[4.5] above the last turn of the secondary.) That comes out to 3.6 but I am well below that. I have almost reached my max adjustment. I can go about another 1/2" very max lower.

The primary coupling with the secondary is about flush. i can come up about a 1/4 in on that.
Adding the new toroid seem to complicate things but it just looks so much nicer.
UPDATE

I lowered the topload as much as I could, I elevated my secondary and instead of tapping at less turns I decided to go the other way and clamped it at turn number 11. I also added a break out point and that drastically reduced the corona atop the secondary.
id like to add another photo and a cool slow motion video.
120 FPS

240 FPS

quite a long streamer!

 

[Sigurthr]

Excellent video and performance! Seems like you're really narrowing down the fine tuning. Have the racing arcs stopped now?

 

[Seoul_lasers]

nice coil, great setup you've got going there.

I'm hearing loud sputtering at the gap which I'm going to suggest that your gap might be too far apart with the tuning you've got right now.
try moving the gap in a hair and see if that popping decreases. I think your primary setting is perfect though.

Nice output. :can:

 

[Sigurthr]

S_L do you mean in the last video or the previous one? Last one was slowed down for playback, I thought it sounded off too but assumed it was artifact of the fps.

Good to see you back in the thread again btw.

 

[Down with Umbrella]

Yes, it's good to see you Seoul_laser, to catch you up to speed it's been a long journey with this coil and I have been getting great help from members here.

@ sigurthr. The racing sparks seemed to have stopped. I didn't notice any when I added that break out point and only 1 when i moved the tuner slightly(once in 3 minutes). It's still too early to say divinity.

Here is a real time video of that same set up. I only posted the slow-mo videos because I thought they were neat.
Note at the bottom of both videos there are interference bars that partially block the view of the spark gap. Can any one explain this? It might not be as obvious in the YT quality videos. I saw this once before when my friend was playing his electric guitar. Also I'm not sure how my iPhone picks up the sound. In person I hear a very consistent sound.

I sent over a request for a 4hv account. I read the rules extensively and plan to lurk for a while before posting to get a feel for the forum. LPF will alway be home tho :na:

 

[Sigurthr]

Note at the bottom of both videos there are interference bars that partially block the view of the spark gap. Can any one explain this? It might not be as obvious in the YT quality videos. I saw this once before when my friend was playing his electric guitar.

See: https://www.youtube.com/watch?v=mQ0hS7l9ckY

Will watch your new vid and edit this post to comment. =)

Let me know if you don't get approved on 4HV in a timely manner, it can take a long time sometimes, and having someone on the inside can help expedite.

Edit: still sounds pretty damn good to me. There's a bit of discontinuous popping but I think that's the camera's (phone's) AGC dropping out periodically and not actually in the real sound. It should sound like a continuous sizzling with no "pause-bap!"'s in there.

 

[Down with Umbrella]

Thanks for the video link. It was very applicable to many things I am interested in these days, especially from an astronomical pov.
Earlier yesterday before the glitch, The Lighting stalker suspected it was my phones AGC.
In person it sounds very consistent, also maybe you didn't notice but my safety gap on my terry filter fired. This doesn't happen often and I'm glad to see it working.

I'll give 4hv some time then get back to you via pm if the delay is to long. My username is the same.
Thanks

 

[USAbro]

That would hurt to touch the bolts no doubt.

 

[Seoul_lasers]

Yes, it's good to see you Seoul_laser, to catch you up to speed it's been a long journey with this coil and I have been getting great help from members here.

@ sigurthr. The racing sparks seemed to have stopped. I didn't notice any when I added that break out point and only 1 when i moved the tuner slightly(once in 3 minutes). It's still too early to say divinity.

Here is a real time video of that same set up. I only posted the slow-mo videos because I thought they were neat.
Note at the bottom of both videos there are interference bars that partially block the view of the spark gap. Can any one explain this? It might not be as obvious in the YT quality videos. I saw this once before when my friend was playing his electric guitar. Also I'm not sure how my iPhone picks up the sound. In person I hear a very consistent sound.

I sent over a request for a 4hv account. I read the rules extensively and plan to lurk for a while before posting to get a feel for the forum. LPF will alway be home tho :na:

The first video with the racing arcs sounded like the sparkgap was set just a hair too far out. Out of tune. The video you've just posted too sounds like the gap is firing fine. :yh:
If you were getting your terry filter to fire, this would explain the loud popping noise I heard. Sounds like you've got your tuning issue solved.

So I'll retract that last comment.

Oh and thanks I'm going to try to be on the forum more often. I have been dealing with re-adjusting to life in Canada.
I'm teaching Japanese at the moment and do part time once in awhile at a local private elementary school.
Trying to get $$,$$$ together for school and to visit wife in S.Korea at the end of summer.

 

[USAbro]

Hey guys. I haven't even touched the coil for the last month, since I made the extra caps. Now at only 5.5nf I'm satisfied. I moved the coil to my basement and am getting strikes to 6". So even if it's not running at full power, I got to move on cause it's taking to much of my time and money and school is more of a priority! But I'm satisfied and thanks to all who helped me out, DWU, Sigurthr, Upaa27, etc oh and of course NOSPIN! Everyone thanks.
This was the first project I've embarked on of this size w/o anyones help like my dad or somebody and u guys made it happen. I had no clue about sparkgaps tuning or anything before I talked to u guys. Now it's a cool display in my basement I play with sometimes. And it was worth all the $150 I put into it along with the $50 wasted from learning but it's been fun.