Increasing secondary diameter from 160 to 200mm

[Phoenix]

Hello everybody,

About a month ago i finished building my first DRSSTC. I am very happy with the results. You can see a small test video with MIDI modulation here:

When i started this project I never thought that i would be able to run my coil up to 1200A. Because of that, i selected a 160mm resonator with 77cm length and 1850 turns. But i think i could get longer sparks with a 200mm resonator that is 100cm long. 1200A is quite a lot for a 160mm secondary.

Would such an increase in diameter make a big difference? Is it worth the work of winding a new secondary and remaking the primary?

Greetings,
Phoenix

[futurist]

I wouldn't change anything Coil works nicely and extra headroom for the current will make sure that IGBTs won't blow up anytime soon

Winding new secondary and rebuilding the primary is almost like building a new coil. I have similar sized coil and thought about upgrading to fullbridge, then making bigger secondary. At the end I gave up and decided to build a new coil at some point

[Mads Barnkob]

Congratulations on the build!

I agree with futurist, don't change a thing, that is a wonderful running coil. If you think you got too many ground sparks and want "longer" sparks from a taller secondary coil, there is a easier and cheaper solution to that, put your coil up on a 50 cm tall platform and fine tune it for maximum spark length again

I kind of went through the same process with my DRSSTC3, kept upgrading stuff on the way and it just took too much money and time, should just have built big from the start or stayed with original design, but it takes building one to learn that.

[Hydron]

The other way to look at it is an excuse to build a second larger coil and run multi-channel midi!

[Phoenix]

Thank you for all your replies 

I am going to leave the DRSSTC like it is now. Maybe i am going to upgrade to a skeleton topload because they look better than the aluminum flex tubing. I also bought a new 70A rectifier because the coil pulls up to 50A peak from one phase during groundstrikes! The old rectifier can only handle up to 35A.

I already own a right sized table as a platform. I am going to give it a try during the next run. If I run the coil on full power i am only getting groundstrikes. The grass in my backyard is already burned up because of the strikes into the soil   

Greetings,
Phoenix 

[Phoenix]

It has been a while but here I have a video of my DRSSTC in a HV-Laboratory recorded with my DSLR instead of the camcorder:

Sadly, I did not have anything on hand to set the coil higher and because of that, I am getting a lot of groundstrikes and the spark length is limited. The coil is not even on full power in this video. But I think that groundstrikes look also really nice with their bright appearance.
Greetings,
Phoenix

[Mads Barnkob]

Great performance and good sound quality, it does not get muddy at all despite playing multiply tones.

You should add a faraday cage made from chicken wire around your DSLR to protect the microphone from EMI, you do not even have to ground it, just have a cage all around it with a hole for the lens and you will get much better sound quality.

[Phoenix]

Thank you very much for subscribing to my channel, Mads 

Actually, the DSLR was behind a farady cage (the whole test area of the laboratory is inside a farady cage) with a mesh size of about 2cm, so i managed to record the video right through the wire cage.

But as you said, a finer chicken wire should bring better results, because there is still some EMI going through the cage (the monitors of a PC started turning on). Thanks for the recommendation.