Author Topic: Skori Mini Tesla Coil questions  (Read 1453 times)

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Offline JwillisTopic starter

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Skori Mini Tesla Coil questions
« on: May 19, 2018, 03:26:30 am »
New project and a few questions concerning the oscillation frequencies.
Here's the website for this project https://translate.google.ca/translate?hl=en&sl=hu&u=http://skory.gylcomp.hu/tesla/mini_tesla.html&prev=search .I used google translate since I can't read Hungarian.I did my best to translate the most important descriptions  the circuit diagram.

Ok The frequency at the 555 is only around 70 Hz. Which seems low for driving  T1 and T2 Mosfets .They get pretty hot even with heat sinks .Of course more heat sinking will be required later but for short tests what I have should do for now.The transformer is a 2:1 but only 11/22 winding's not the prescribed 15/30 .
My coil is different from the original.And the circuit only pulls around 2.5 amps at 13.8 volts.I'm running the PSU in Parallel for 10 amps . 
Now I figure my primary coil should run around 78 kHz not 70 Hz that would put the secondary coil I have at around 505 kHz and the C4 ,L4 oscillator from the example is 400 kHz .These are estimates

Should I kick the 555 to 78kHz  and the C4,L4 oscillator to 505 kHz.Or am I looking at this wrong .

The circuit works sort of but not as good as what it could be .
Pardon the mess and lighting .I'm still in the process of wiring my lab  .And don't make fun of my toroid .Took me all day to make that .I'll make a better one later.

 

Offline alsetalokin4017

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Re: Skori Mini Tesla Coil questions
« Reply #1 on: May 19, 2018, 04:24:00 am »
I think the way this is supposed to work is that the 555 produces a square-ish pulse train to the primary that starts the secondary ringing. Once it rings, the feedback circuit takes over and should drive the primary at the secondary's resonant frequency. So the actual frequency of the 555 is rather unrelated, you are just using the edges of a low-frequency pulse to start the ringing process. I think. The way the schematic is laid out makes it a little difficult to interpret.
It seems that this also works as an "interruptor" so that the coil will be working in staccato mode.

So I'd stick with the specified component values unless someone else has a better idea about how the circuit works.

You might try "phasing" the primary coil: that is, reverse its connections and see if that makes any difference in the performance and current draw. Ditto with _one_ winding of the toroidal transformer. SO that's 4 different phase configurations to try.

But seriously... lose the breadboard and put this circuit together either with the PCB or by using another prototype method involving soldered connections and perhaps a ground plane.
« Last Edit: May 19, 2018, 04:29:51 am by alsetalokin4017 »
The easiest person to fool is yourself. -- Richard Feynman
 


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