High Voltage Forum

Tesla coils => Vacuum Tube Tesla Coils (VTTC) => Topic started by: kaboooom2000uk on April 30, 2021, 09:34:11 AM

Title: My first VTTM (Vaccum tube tesla magnifier) WIP
Post by: kaboooom2000uk on April 30, 2021, 09:34:11 AM
Hello Ladies and Gentlemen, I present my VTTM which I believe may be a first as I haven't seen any circulating the internet, seen plenty of classic spark gap derived machines, but none where they employ a tube oscillator. Mine uses a little 830B tube which seems to perform well and provides about 6" arcs.

here I use a simple schematic from an induction heater but I have modified the work coil to work at the same Fres as my secondary (which I established using the signal generator and scope method as I find it simpler to do this) and built it using parts around the shack. As you can see the circuit itself is very simple. Only real changes I made to it are making both the feedback and the primary resonant at the same freq as the resonator coil

Basic setup, but instead of spark gap I am driving it with an oscillator.

In my version I use a tightly coupled "driver" coil made from about 100 turns of litz wire wound on a borosilicate glass lantern chimney, which serves as a former, the primary is about 20 or so turns of thicker litz wire I made using some magnet wire and a drill which sits on its own former.

The feedback winding is about 5 turns of more litz wire. I wound that on a acrylic tube which sits over the other coils for simple removal and modification.

Power input was conceived using a pair of 650-115 transformers, I hooked them up backwards, to step up and the 115V windings were wired in series and fed with my 8A 240V variac. so I had about 1400V or so to play with at about 1KVA which is the limit of the transformers. This AC is then fed into a simple level shifter composed of a dual diode package and a 220uf 2500V capacitor, and 4700pf ceramic decoupler cap.

From the footage I took it appears to be working, I would say this because it appears the input voltage to the resonating coil is very low but then gains voltage the further up the coil I go.

I hope to get some more refinements done on this at some point but its been put on the hiatus while I play with solid state stuff. Namely my half-bridge universal driver.
SimplePortal 2.3.6 © 2008-2014, SimplePortal