Re: Question regarding PCB board in close proximity with Primary Coil (DRSSTC)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>

I know you don't want to use wires, but if the circuit
board doesn't work, why not use just the LED's
connected with a twisted shielded pair?

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> Original poster: Vardan
> <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi,
>
> You can actually directly power them from the
> primary.
>
> Assume the voltage across the primary coil is
> 15kVrms and it is 50
> feet long.  That is 25 volts per inch.  If the LEDs
> run off 25 mA,
> just hook two wires to the primary 1 inch apart with
> a series 1000
> ohm resistor.  You have to run perpendicular though
> for a distance to
> escape the direct fields of the primary.  Of course,
> they would only
> light while the primary is energized in proportion
> to the current
> level.  You also should have a reverse diode in
> there.
>
> Or, if you fiddle with it, you might run a stray LED
> with the two
> leads sticking out parallel to the primary at some
> distance to pickup
> the stray current.
>
> The LEDs could also just go to small "loops" in the
> board to
> inductively pull the needed current.
>
> More conventionally, you just have to avoid that
> full shorted turn
> and decouple the supply lines with "really good "
> caps.
>
> If you really want to go for the engineering prize.
> Make a many turn
> loop coil in the board to pick of the primary
> current and use the
> LEDs in the burden circuit.
>
> Cheers,
>
>          Terry
>
>
> At 05:59 PM 5/7/2006, you wrote:
> >Hi Dan,
> >
> >Your idea to illuminate the primary supports is
> novel.  A "modded"
> >coil.  Surely you can inductively power the led's
> from the primary?
> >Just a thought...
> >
> >
> >Karl
> >
> >
> >On May 7, 2006, at 7:26 PM, Tesla list wrote:
> >
> >>Original poster: "Daniel McCauley"
> <dhmccauley@xxxxxxxxxxxxxxxxxxxxxxxxxx>
> >>
> >>Here is an interesting problem I am currently
> facing with one of my
> >>projects. Basically, i have a tesla coil with 6
> primary
> >>polycarbonate supports which will be illuminated
> via LEDs (from
> >>underneath the base as shown in the attached
> image)
> >>
> >>Now, i would ideally like to use a PCB board to
> mount the LEDs and
> >>this PCB board would then screw directly
> underneath the base where
> >>the LEDs would protrude through the base and up
> into the bottom of
> >>the primary supports. This keeps everything nice,
> neat, and compaq
> >>with out having six million wires all over the
> place.
> >>
> >>However, the problem is that i am not quite sure
> how the board
> >>would act in close proximity with the primary coil
> which is only
> >>about 2-3 inches above this PCB board.
> >>
> >>Option 2 and 3 both seem to be the worse of the
> group since they
> >>will couple with the primary like a shorted or
> partial turn, respectively.
> >>
> >>Option 1 seems like a possible alternative, but
> i'm not sure how
> >>that would work. And Option 4 with the flying
> leads may be the only
> >>feasible option.
> >>
> >>Anyways, what are your thoughts on Option 1?
> >>
> >>Any other thoughts or ideas you may have???
> >>
> >>Again, my concern isn't how the PCB board would
> affect performance
> >>of the coil but rather it is the concern of
> induced noise onto the
> >>PCB board which would screw up the control voltage
> powering the LEDs.
> >>
> >>Attached image shows application and possible
> options for PCB board
>
>>http://www.easternvoltageresearch.com/led_question.jpg
> >>
> >>Thanks
> >>Dan
>
>
>