Hi Thomas,The quick answer is yes, but the design can be a bit tricky. There are many ways, but all methods rely on being able to prevent the main spark gap from directly shorting out the HVDC supply.
A fairly elegant method uses a relatively large DC storage cap, an inductor and a high voltage blocking ("de-Q'ing") diode in a technique called DC resonant charging. This approach has the advantage of almost doubling the eventual voltage developed across the tank cap. This is the method Greg Leyh used on his large Electrum coil, and similar approaches are used extensively in many pulsed power applications. These systems are very efficient but may require a bit of balancing between inductor and tank cap sizes, gap dwell time, and gap break rate.
Another method simply charges the tank cap through a power resistor from the HVDC source. Although considerably less efficient than DC resonant charging, it will work and has the advantage of being simple. This approach burns up about 50% of the total input power in the series resistor.
Another method uses a clever arrangement of switching (via a properly configured rotary spark gap) to disruptively charge the tank cap from a "stiff" DC source (a larger HVDC storage cap). Similar to an H bridge, the spark gap reverses the charging polarity to the tank cap on alternate gap electrode presentations. Each "bang" does two things simultaneously:
1. disruptively charges the tank cap to the opposite polarity (from the previous bang) through the primary winding
2. The high current tank capacitor charging transients power the TC primary with a oscillatory waveform
Steve Young has used this approach with great success. As with resonant charging, this method effectively doubles the HVDC supply voltage seen by the tank cap, but it does not require a large inductor and de-Q'ing diode. This can be advantageous, since doubling the tank cap voltage quadruples the bang size for a given tank cap. Check Richie Burnett's site for details and equations on resistive and resonant charging:
http://www.richieburnett.co.uk/dcresist.htmlSearch the Pupman archives for the terms such as "DC Coil","H bridge RSG", "DC Resonant charging", and "DC H-Bridge" for additional information.
Good luck, Bert Ryckmans, Thomas wrote:
Mmh I did read the Wikipedia entry beforehand, but I am still wondering... I have a few solid-state NSTs, 15kV, that I used to power a Jacob's ladder. My question is, basically, "can one power a TC with a high voltage DC source"? Many thanks Thomas -----Original Message----- From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of Mddeming@xxxxxxx Sent: 16 April 2008 16:59 To: tesla@xxxxxxxxxx Subject: Re: [TCML] SMPS as voltage source for a tesla coilIn a message dated 4/16/08 11:27:32 A.M. Eastern Daylight Time, Thomas.Ryckmans@xxxxxxxxxx writes:Hello, I am sure this has been debated to death... but I can't find it. Can one use a SMPS to drive a Tesla coil? I understand that SMPS are high frequency (>20 kHz) but what about rectifying this input? The tank cap would get charged to breakpoint, the spark gap will fire...etc. I think Greg is using this with a MOT setup (this give a 60 Hz pulse, while rectifying a SMPS would give a 20 kHz pulse). I am asking this because I find it difficult to source cheap NST in UK, while SMPS are easier to find Cheers Thomas Hi Thomas,This may offer some useful background_http://en.wikipedia.org/wiki/Switched-mode_power_supply_ (http://en.wikipedia.org/wiki/Switched-mode_power_supply) Matt D**************It's Tax Time! Get tips, forms and advice on AOL Money & Finance. (http://money.aol.com/tax?NCID=aolcmp00300000002850)_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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