Hi list
I tryed yesterday to prepare a new secondary for one of my VTTC and I observed something interesting. It seems that the secondary winding direction does matter indeed. So, I made a few experiments and movies.
In the first movie I used a secondary with the same winding direction as the primary coil. 200 Vac input. The VTTC is CW type (full rectification). No problems at all when drawing arcs to the ground.
https://www.youtube.com/watch?v=FqeE_X1D05o&list=UUzbD9f1_jvc3K00xii4XgdA
In the second movie, the secondary and the primary have opposite winding direction. 200 Vac input. Tuned for the best spark. It does not need to change the feedback coil connections. It works, big spark, awsome, but somehow more disruptive than with the first secondary. When drawing arcs I can see voltage spikes, as breakdowns, on the primary cap.
https://www.youtube.com/watch?v=ePTvOMJsI0M&list=UUzbD9f1_jvc3K00xii4XgdA
In the third movie I put again the first secondary to verify if there are some damages of the primary cap (to exclude possible bias). It works OK.
https://www.youtube.com/watch?v=32EG7L3VOvk&list=UUzbD9f1_jvc3K00xii4XgdA
So, the winding direction of the coils does matter, at least in VTTCs setups. Using opposite winding direction coils (well, you can repair this just changing the primary coil connections) can lead to possible primary cap failures, even it is well calculated. The VTTC work in both condition, the sparks is there, ok, but if you dont know you can overvolt your cap when arcing to ground. My guess is this principle is responsible, even in SGTCs for some unexpected primary cap failures. But this is another story.
vasil
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