Cascaded current transformers are used from a practical view point. The first toroid has 33 windings and 1 turn of this goes through the second toroid, which also has 33 windings. This gives a 33×33 = 1089 current ratio from the primary cable passing through the first toroid. If you were to use a single toroid, you had to wind 1000 turns on it, usually by hand and that is tiresome and not very practical.

A single current transformer will work fine, some even uses 100 turns and a different shunt resistor value to match it, but you have to watch for phase shift and such when you do that.

Kind regards

Mads

I would like to equip my OneTesla TS with an OCD. However, I have noticed that the power sensing is made by two toroids glued to eachother while only one of them hangs in the primary loop. Can someone explain to me thy there are two toroids and how they are wound and connected to eachother? Would it not work with a single toroid?

Thanks for your help.

]]>The short answer: Here you find the LC circuit theoretical limit, what you set your OCD to will limit this and you can push it for longer as it cuts out once in a while. This calculation also does not take into account that you transfer this energy from the primary circuit to the secondary circuit and out into the load that a spark is. So once the energy is transferred through the system, it should not continuesly be rising, but be “stable” and feed into the spark. This is why you see me running 35 primary cycles.

About AC current, I think it is easiest to look at the DC bus capacitor calculations.

Sign up at http://www.highvoltageforum.net and tell about your project and you will have many more people helping you ðŸ™‚

Kind regards

Mads

I am planning to build my first DRSSTC. I read your designe guide and tried to use the formulars on this “example” coil to check if I am doing things right.

Unfortunately i got some different results and I dont know why.

For example: if i use the formula for the maximum On-time from the MMC design guide on this coil with a peak Voltage of 3200V (for the 4000VDC Cap) and 210*sqrt(2) supply Voltage, my result is about 11 half-cycles. In reality you are using 35 primary cycles which is obviously a lot more. Is this the result of de-tuning the primary? so current and voltage rising slower?

And is their an easy way to calculate the AC input current?

I would be very happy if someone could help me with this.

Kind regards

Kai

I do not build that many SGTC, so I do not use neon transformers, I do solid state inverters with IGBTs and such.

That being said, you still need a large peak current handling capability in a spark gap Tesla coil, the 30 mA rating of the transformer does not have much to do with the energy circling in the LC circuit.

For calculating the correct MMC for a SGTC, use JavaTC MMC calculator, scroll down to “power calculations”: http://www.classictesla.com/java/javatc/javatc.html

Kind regards

Mads

You calculate the charge time from the RC time constant of each stage and the voltage multiplication is just the number of steps times the input voltage.

Kind regards

Mads

can i get your formulas which you use it ?

thanks for your help ]]>

please help

can i use 20kv 0.05-0.5 if so i still dont know about strings ]]>