Setting The Primary Frequency Lower Then The Secondary.

[Hysteresis]

I know this is an old topic but is there anyone that does NOT believe in doing this? I just got a bigger toroid and retuned my coil today. New Fs=86.1KHz and Fp set to 82.0KHz.  It's a big outdoor coil 6000watts.  I'll be firing it up Monday night 9-16-2024.

[Mads Barnkob]

Tuning your primary 5-10% lower than your secondary, will help grow longer arcs, as you that way accomodate for the spark load on the secondary. Large sparks will pull the frequency nearer to the primary and thus grow them even longer. It does however also take higher voltage/longer on-time before you grow sparks, with heavy detuning.

You can show it in practise very easily with a string of copper wire. Thin wire, non enameled, like the length of your spark. You can even add some 5-6 branches of copper wire. Now measure your secondary and you can see the load of the copper wire dropped the secondary resonant frequency.

Luckily we leave believing for the places where people fold their hands or leave the footwear at the door.

[MRMILSTAR]

You can use JAVATC to model a long streamer and see the effect on primary and secondary tuning.

[Hysteresis]

I ran the coil last night with the bigger toroid 36x8, it work super good! I think it even better then the smaller toroid. Tuning was Fs=89.1KHz, Fp=83KHz.

[Benjamin Lockhart]

What spark length were you getting? Any pictures?
It has been my experience that big toroids are always better because they reduce the effect of spark loading dropping the secondary frequency, and you want to tune the primary to the loaded frequency of the secondary.

[Hysteresis]

Tesla coil and a bad moon rising. About 8.5 feet.

[Hysteresis]

One more photo of moon and coil.

[davekni]

Great images!  Thank you for sharing.

[Hysteresis]

Over exposed photo from last night. Last one I promise.

[Benjamin Lockhart]

Very nice! that looks almost the same as my DRSSTC which has the same exact size toroid and does 8.5 feet.
What did you use to take the pictures?
This is a video still.

[Hysteresis]

Hi Benjamin. I want a big DRSSTC like yours! The photos were taken with a Nikon D7500 DSLR.