Telsa coil power supply
Robert Mani, Thu May 24 2007, 06:39PMHello,
Can somebody explain to me why for building a tesla coil , one needs to use
a neon power supply with an iron core and not the new type of electronic neon sign power supplies
that look like a PC adapter. I have found an old fashioned version on e-bay and am about to buy it
but first need to know the reason why one would work and the other would not.
(PS: I have tried the new models and know for a fact that they do not work with tesls coil)
Re: Telsa coil power supply
GreySoul, Thu May 24 2007, 07:48PM
Higher frequency? Square waves? Current limiting?
All of the above?
GreySoul, Thu May 24 2007, 07:48PM
Higher frequency? Square waves? Current limiting?
All of the above?
Re: Telsa coil power supply
Sulaiman, Thu May 24 2007, 07:55PM
A 'traditional' NST operates as a step-up transformer at the ac line frequency (50 or 60 Hz)
and due to the magnetic shunts the output appears as though there is a very large series inductance.
The value of the primary capacitor is chosen so that it resonates with the output inductance at the line frequency.
(actually a slightly higher value capacitance is better to get the most power from the NST without 'killing' it.)
Ideally the spark gap will fire once per half-cycle of the mains frequency, so the spark-rate is twice the line frequency (100 or 120 sparks/second).
The new NSTs operate at about 20 kHz (just above audible) allowing a much smaller/lighter/cheaper transformer to be used.
Operating at 20 kHz doesn't give time for the usual values of primary capacitor to fully charge during each half-cycle so the spark gap will never 'fire'.
Ideally you could use fast high voltage diodes to rectify the output to repeatedly charge the primary capacitor to operate the spark gap, but there are a few complications that makes this a less than ideal system.
Sulaiman, Thu May 24 2007, 07:55PM
A 'traditional' NST operates as a step-up transformer at the ac line frequency (50 or 60 Hz)
and due to the magnetic shunts the output appears as though there is a very large series inductance.
The value of the primary capacitor is chosen so that it resonates with the output inductance at the line frequency.
(actually a slightly higher value capacitance is better to get the most power from the NST without 'killing' it.)
Ideally the spark gap will fire once per half-cycle of the mains frequency, so the spark-rate is twice the line frequency (100 or 120 sparks/second).
The new NSTs operate at about 20 kHz (just above audible) allowing a much smaller/lighter/cheaper transformer to be used.
Operating at 20 kHz doesn't give time for the usual values of primary capacitor to fully charge during each half-cycle so the spark gap will never 'fire'.
Ideally you could use fast high voltage diodes to rectify the output to repeatedly charge the primary capacitor to operate the spark gap, but there are a few complications that makes this a less than ideal system.
Re: Telsa coil power supply
Shaun, Thu May 24 2007, 11:24PM
Wow, was I lucky. When I built my first SGTC, I selected an NST based only on its power ratings (15kV 30ma). I had no idea these little ones didn't work. I've never heard anything about not using these smaller ones, but I guess I'll have to be more careful from now on.
Shaun, Thu May 24 2007, 11:24PM
Wow, was I lucky. When I built my first SGTC, I selected an NST based only on its power ratings (15kV 30ma). I had no idea these little ones didn't work. I've never heard anything about not using these smaller ones, but I guess I'll have to be more careful from now on.
Re: Telsa coil power supply
Ken M., Fri May 25 2007, 12:48AM
I've gotten one of the electronic ones to work, but it was extremely ineffective, also after about 10secs of use there was a catastrofic failures within the unit.
Ken M., Fri May 25 2007, 12:48AM
I've gotten one of the electronic ones to work, but it was extremely ineffective, also after about 10secs of use there was a catastrofic failures within the unit.
Re: Telsa coil power supply
ragnar, Fri May 25 2007, 07:37AM
Reading the most recent threads, I'm noticing that bad spelling seems to be rampant.
Please:
doubler, not "dubbler" (or "dubler", for that matter!)
catastrophic, not "catistrofic"
rectifier, not "rectifyer"
I know I sound like a grumpy person bitching, but many find it very irritating. The same goes for punctuation; it probably scares new (literate) members away. Please, make an effort, or use a spellchecker.
ragnar, Fri May 25 2007, 07:37AM
Reading the most recent threads, I'm noticing that bad spelling seems to be rampant.
Please:
doubler, not "dubbler" (or "dubler", for that matter!)
catastrophic, not "catistrofic"
rectifier, not "rectifyer"
I know I sound like a grumpy person bitching, but many find it very irritating. The same goes for punctuation; it probably scares new (literate) members away. Please, make an effort, or use a spellchecker.
Re: Telsa coil power supply
Cain, Fri May 25 2007, 04:22PM
try opera as your browser it has its own spell check
Cain, Fri May 25 2007, 04:22PM
try opera as your browser it has its own spell check
Re: Telsa coil power supply
GreySoul, Fri May 25 2007, 05:22PM
Firefox 2.0.x.x also has a built in spell check.
I'm 100% with BP on this one. I've been online for about 14 years now and my spelling, as atrocious as it is, has never APPEARED better since the release of Firefox 2.0.something.
Of course, "double" shouldn't require a spell check to get right. If you can't spell at a grade school level you probably shouldn't be playing with this sort of stuff anyways.
May I offer you this lovely orange Nerf ball instead?
</threadjack>
(if English is your second language ignore most of my rant, your effort is more than most Americans put forward in communication, but a spell check can't hurt)
-Doug
GreySoul, Fri May 25 2007, 05:22PM
Firefox 2.0.x.x also has a built in spell check.
I'm 100% with BP on this one. I've been online for about 14 years now and my spelling, as atrocious as it is, has never APPEARED better since the release of Firefox 2.0.something.
Of course, "double" shouldn't require a spell check to get right. If you can't spell at a grade school level you probably shouldn't be playing with this sort of stuff anyways.
May I offer you this lovely orange Nerf ball instead?
</threadjack>
(if English is your second language ignore most of my rant, your effort is more than most Americans put forward in communication, but a spell check can't hurt)
-Doug
Re: Telsa coil power supply
Ken M., Sat May 26 2007, 04:22AM
My Apologizes BP, Greysoul, and the rest of 4hv forums, for the lack of spell check, and I’m guessing horrible punctuation on any of the posts I’ve made.
Ken M., Sat May 26 2007, 04:22AM
My Apologizes BP, Greysoul, and the rest of 4hv forums, for the lack of spell check, and I’m guessing horrible punctuation on any of the posts I’ve made.
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