My Tesla Coil.

[sm0ky2]

So, I am building a (huge) Tesla coil


I have calculated the desired frequency to be ~492kHz
(491.78kHz)


does anyone know of a simple oscillator that can be tuned to this?


Also, is a spark gap "necessary"?
Or is this simply remnants of an old-world convenience?
I.e.: an modern a/c oscillator by itself could run the primary

[sm0ky2]

Ok, I answered the spark gap question


No, we don't need a spark gap.
That's just an old way of controlling frequency
There are many Tesla coils that operate straight
from a signal generator.


So, next issue:
Every reference I have found shows coils being wound with
only ONE wire!!!!!!  I don't understand this.
Tesla Clearly wrote about why we should construct this device
using Bifilar coils.... for both primary AND secondary!!
So, this is what I am doing.


My next question is:  how to wire it up?
My assumption is to connect the top most wire to the top load
and bring the bottom of that winding back up to the top of the 2nd winding.
(should the return lead be positioned away from the coil?)
There is little reference to people making bifilar secondaries.
Any help here would be great.
Also, since the field is doubled, how does this change the inductance equation?
Which, in turn, changes the SRF of the coil....

[sm0ky2]

Any of you Tesla Coil owners using a Bifilar secondary?






BTW:
If enough people owned Tesla coils, and we standardized some set of frequencies
We can build our own wireless power grid.
Stationary And portable receivers

[Raycathode]

Ok, I answered the spark gap question

No, we don't need a spark gap.
That's just an old way of controlling frequency   What

then take the suppressors out of your vacuum cleaner and see what it does to your tv sound and video then try your radio! 

There are many Tesla coils that operate straight from a signal generator.

that's not a real Tesla coil ass your using the transistor to turn the coil on and off like a sine wave a spark gap or interrupter would pulse it and jam everyone's radio reception in close proximity     

Fun ainit !

Raymondo

[Raycathode]

So, I am building a (huge) Tesla coil


I have calculated the desired frequency to be ~492kHz
(491.78kHz)

What is so special about that frequency?

does anyone know of a simple oscillator that can be tuned to this?

use a crystal and devide it down as close as you can to that frequency ie divide by 2 then use a shift register and knock off bits easy but you will have to use logic a micro will just keep falling over.

Also, is a spark gap "necessary"?
Or is this simply remnants of an old-world convenience?

well if you don't use a spark gap how do you charge a cap and then dump iy across the secondary coil
you could use MOSFETS but they are expensive if you blow them up IGBT#s have losses across them at lovw voltage like bipolar transistors and charge time will change coil frequency and resonance.

I.e.: an modern a/c oscillator by itself could run the primary