Re: schematics...Adam Smith's
> Original Poster: "Harvey D Norris" <Tesla4-at-excite-dot-com>
> Adam wrote;
>> Here is my schematic:
>> It's exactly what I'm building, except that where there are 6k resistors
>> shown, it should read 3k. Each leg actually has two 6k in parallel for
>> more power handling, so it is really 3k ohms per leg.
> I am pretty new to all these precautionary measures people indicate as being
> necessary for rf kickback ect. My first question is doesnt the total 6,000
> ohms of resistance in the primary circuit limit your possible performance?
The resistors probably dissipate somewhere in the range of 80-120 watts at
full operating power. This is the price I've chosen to pay in order to
better protect my NSTs. If you want to put every last watt into your spark,
you can forgoe the resistors and caps, and open up your gap nice and wide.
The candle that burns twice as bright...
> Doesnt the 5.5 mH RF choke contribute a significant portion of the total
> inductance in the primary circuit, thus changing the main needed tank C
No, the chokes are not part of the tank circuit. When the spark gap breaks
down, the circuit becomes the main gap, the main cap, the primary coil, and
whatever conductors connect them.
> Hasnt RF chokes fallen out of favor and is this a reason why?
They have, but I'm not convinced. My current opinion is that most people are
building them incorrectly, and using them incorrectly. I put all the
details in my reply yesterday to another thread now titled "Paul's Design
(no subject originally)".
> Also the 2 500 pf caps grounded from the center, are these exclusively a
> safety precaution and/or could they be in the range of value to function as
> what was termed resonant mains or resonant recharging where a small value of
> capacity is used that is resonant to the NST open secondary inductance -at- 60
They 500pF caps are just there to divert high-frequency transient noise to
ground, away from the NST. Together with the chokes and resistors, these
make a 2nd order RLC lowpass filter. For a critically damped filter, I
really should have more like 4.5k per leg, but I just have to work with the
resistors I have found at this point.
> Lastly the power factor capacitor, is this now commonly employed by
Only those who are reaching the current handling capabilities of their
electrical service or variacs. I have a nice big variac, but I needed to
add the PFC caps to stop the 20amp breaker from tripping at full power input
to my system.
Hope that helps somewhat.