Desktop Coil
Art, Thu Jan 07 2016, 03:06AMHi Guys,
I’ve done some slayer exciters, and learned some fundamentals such as how the self-tuning works.
It’s on the more powerful end of those. Ie. can light a 4 ft commercial neon,
but now looking to ramp it up to something that can throw some small streamers into the air.
Are the ZVS modules on eBay any good generally?
I presume since they are driven at their own frequency,
I’d still need a capacitor and spark gap to tune to the coils’ frequency?
(at least if there was no feedback from the coil to trigger the LC circuit in the ZVS module).
Cheers, Art.
Re: Desktop Coil
Sigurthr, Thu Jan 07 2016, 03:31AM
Some are decent. I've successfully used the parallel LC type which uses two inductors. I prefer them greatly over the traditional single inductor center-tapped primary type.
Using ZVS for a tesla coil HV supply means you're going to have to essentially make a traditional SGTC out it, or make a secondary that resonates at the ZVS's natural drive frequency. If you make a secondary resonant at the ZVS's f0 then it essentially becomes a push-pull (single inductor) or parallel LC CW DRSSTC (dual inductor). Obviously the hard part of this is matching up all the resonances. Going the spark gap route you don't need a charging inductor or diode like the traditional DC resonant SGTC needs since a flyback's output is short-circuit tolerant, but you'll still need to follow normal guidelines for tesla tank circuit creation and tuning.
Note that most eBay drivers don't come with a transformer/flyback so their listed drive frequency won't be correct. The natural frequency of the ZVS driver is a result of the primary coil you wind on the connected transformer and the tank capacitance on the driver.
Sigurthr, Thu Jan 07 2016, 03:31AM
Some are decent. I've successfully used the parallel LC type which uses two inductors. I prefer them greatly over the traditional single inductor center-tapped primary type.
Using ZVS for a tesla coil HV supply means you're going to have to essentially make a traditional SGTC out it, or make a secondary that resonates at the ZVS's natural drive frequency. If you make a secondary resonant at the ZVS's f0 then it essentially becomes a push-pull (single inductor) or parallel LC CW DRSSTC (dual inductor). Obviously the hard part of this is matching up all the resonances. Going the spark gap route you don't need a charging inductor or diode like the traditional DC resonant SGTC needs since a flyback's output is short-circuit tolerant, but you'll still need to follow normal guidelines for tesla tank circuit creation and tuning.
Note that most eBay drivers don't come with a transformer/flyback so their listed drive frequency won't be correct. The natural frequency of the ZVS driver is a result of the primary coil you wind on the connected transformer and the tank capacitance on the driver.
Re: Desktop Coil
Art, Thu Jan 07 2016, 09:44AM
Ok, thanks, that’s a start. Yes, that’s what I was thinking,
it would still be a spark gap coil after the ZVS driver.
Maybe back with more questions after I’ve done the shopping :)
Art, Thu Jan 07 2016, 09:44AM
Ok, thanks, that’s a start. Yes, that’s what I was thinking,
it would still be a spark gap coil after the ZVS driver.
Maybe back with more questions after I’ve done the shopping :)
Re: Desktop Coil
jdub1581hv, Thu Jan 07 2016, 06:19PM
I too have wanted to get a ZVS coil going, but it is not that easy to achieve breakout.
Here is an easy circuit that performs rather well for how simple it is (forgot members name who came up with it).
I often use it to test my mosfets too.
The circuit likes more turns on the primary (10 - 20) wound close to secondary..
Depending on the Resistor divider you can give it up to 1/2 the mosfets voltage rating.
I can pull a 2" arc from my 6" x 24" resonator at only 18v
jdub1581hv, Thu Jan 07 2016, 06:19PM
I too have wanted to get a ZVS coil going, but it is not that easy to achieve breakout.
Here is an easy circuit that performs rather well for how simple it is (forgot members name who came up with it).
I often use it to test my mosfets too.
The circuit likes more turns on the primary (10 - 20) wound close to secondary..
Depending on the Resistor divider you can give it up to 1/2 the mosfets voltage rating.
I can pull a 2" arc from my 6" x 24" resonator at only 18v
Re: Desktop Coil
woodchuck, Thu Jan 07 2016, 08:43PM
That is an interesting clamp!
woodchuck, Thu Jan 07 2016, 08:43PM
That is an interesting clamp!
Re: Desktop Coil
jdub1581hv, Thu Jan 07 2016, 10:09PM
Should note that the Tank cap in the pic is an arbitrary number, and should be set for resonance..
If Oscillation fails (no cap) reverse primary leads..
I found that adding the tank cap can cause excess heating in the FET.
What I did again, was to reverse the primary leads (where it was working w/o cap).
jdub1581hv, Thu Jan 07 2016, 10:09PM
Should note that the Tank cap in the pic is an arbitrary number, and should be set for resonance..
If Oscillation fails (no cap) reverse primary leads..
I found that adding the tank cap can cause excess heating in the FET.
What I did again, was to reverse the primary leads (where it was working w/o cap).
Re: Desktop Coil
Art, Fri Jan 08 2016, 03:06PM
Hi again all :) When I was starting to think about a bigger one,
I got myself a neon former, and at the same time a 4 ft neon.
I’ve since fallen in love with the neon and want o keep them together :rolleyes:
I didn’t think much of a ZVS driver until I saw a similar thing driving some quirky
ozone facial mask for supposed beauty treatment.
Once gutted, the thing can be run, and some fun be had.
Art, Fri Jan 08 2016, 03:06PM
Hi again all :) When I was starting to think about a bigger one,
I got myself a neon former, and at the same time a 4 ft neon.
I’ve since fallen in love with the neon and want o keep them together :rolleyes:
I didn’t think much of a ZVS driver until I saw a similar thing driving some quirky
ozone facial mask for supposed beauty treatment.
Once gutted, the thing can be run, and some fun be had.
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