Re: About OLTC's
Finn Hammer, Fri Sept 22 2017, 06:47PM

|)4+80!|-|\\/ ( I wonder what you are trying to say with your nic)

The OLTC was a classic disruptive TC, with a twist: The sparkgap was replaced with an IGBT Brick. Another characteristic of the coil was it's low initial voltage on the primary capacitor.
By using a resonant charging scheme with a series inductor and rectified power from between 2 phases of 400V AC, (which is the standard here in most of europe) the first bang could be delivered at 560V and all the following bangs in a burst would be delivered at 1120V. It follows that to get proper bang energy, the primary capacitor had to be large and thus, the primary coil very small. 1 and 2 turn primary coils were the norm.
Steve Conner made a very elaborate driver for the OLTC, and one of these coils is still in operation at Danfoss Universe 12 years after, so it i a very reliable topology.
Another iteration of the topology was the merge of the brick "spark gap" and the Sidac gate drive topology, which Terry Fritz ideated.
This author merged these two topologies together with a trigger circuit for the Sidacs, and the T-BRISG coil was born.
This topology was used in the V-Twin coil that was on show at Palais de Tokyo in Paris about 8 years ago.

This is the last coil of its kind that I am aware of, but I don't know for sure.
So, why are nobody building these kinds of coils anymore?
I think it is because the primary circuit needs a heavy hand and some rather thick copper to make the coil work. My coils had primarys made from 2.5mm thick copper strap, 50mm wide, and all in all, it was not trivial to make the stray inductance small enough in relation to the coupled inductance in the coil.
It is a mechanical problem, I think.
But why don't you go ahead and build one, resurrect the old dinosaur! It is almost impossible to kill, unlike it's more recent counterparts, which frequently blow up without apparant cause.....

Cheers, Finn Hammer

Re: About OLTC's
|)4+80!|-|\\/, Sat Sept 23 2017, 09:29AM

|)4+80!|-|\\/ ( I wonder what you are trying to say with your nic)

It says DatBoiHV in UlTIMATE LEET(#ImSoEdgy)

By using a resonant charging scheme with a series inductor and rectified power from between 2 phases of 400V AC, (which is the standard here in most of europe) the first bang could be delivered at 560V and all the following bangs in a burst would be delivered at 1120V. It follows that to get proper bang energy, the primary capacitor had to be large and thus, the primary coil very small. 1 and 2 turn primary coils were the norm.

Correct me if I'm wrong but,won't this topology be much more powerful than the standard half bridge or full bridge SSTC's built nowadays??

But why don't you go ahead and build one, resurrect the old dinosaur! It is almost impossible to kill, unlike it's more recent counterparts, which frequently blow up without apparant cause.....

AW HELL NAW
I'm in the process of making my first SSTC & am a complete newbie at building tesla coils or HV projects in general.

Maybe Someday....

Steve Conner made a very elaborate driver for the OLTC, and one of these coils is still in operation at Danfoss Universe 12 years after, so it i a very reliable topology.
Another iteration of the topology was the merge of the brick "spark gap" and the Sidac gate drive topology, which Terry Fritz ideated.
This author merged these two topologies together with a trigger circuit for the Sidacs, and the T-BRISG coil was born.
This topology was used in the V-Twin coil that was on show at Palais de Tokyo in Paris about 8 years ago.

Secondly, That sounds rather complicated...

Re: About OLTC's
Finn Hammer, Sun Sept 24 2017, 03:22PM


Corrected. The longest sparks made by OLTCs is 2 meters

Cheers, Finn Hammer