Part of my issue is that given my living situation, I am often using a
counterpoise, not a fixed earth ground, as the RF ground. I use a large
(24" x 24") metal sheet for the RF ground This has worked well at least as
far as the coil seems to be producing decent arcs even in the "untuned"
state.
Connecting my NST ground to the counterpoise also connects it to the safety
spark gap. As I want overvoltages to go away from the NST, it seems
counterintuitive to have the NST ground connected to the counterpoise. NST
referenced to mains ground gives the NST center-tap a fixed ground
reference; the safety gap over-voltages divert off to the counterpoise.
Alternatively: If you were going to run a tesla coil inside a building,
where the only available fixed ground was mains ground, what solution would
you use?
Joshua Thomas
On Tue, Nov 23, 2021 at 9:07 PM Chris Reeland <chrisreeland@xxxxxxxxx>
wrote:
> Hi Joshua,
>
> Well, me I have some issues with how you have grounded now...you have a
> case of the coil circuit using 2 grounds from what you are saying.
> Hopefully some others will chime in soon and possibly agree with me.
> Probably reopening this "can of worms" now...
>
> Me on my coil , I use RF ground on the NST.
>
> Can not really help on winding myself...too busy with so many things...
> maybe someone here will volunteer at a decent price...and possibly not.
> Some commercial offerings I have seen in the past is not cheap at all for
> secondaries!
>
> Chris Reeland
> Ladd Illinois USA
>
> Sent from my Lenovo Tablet
>
> On Tue, Nov 23, 2021, 7:52 PM Joshua Thomas <joshuafthomas@xxxxxxxxx>
> wrote:
>
>> I haven't had the chance to change the wiring yet, but I have decided to
>> have the NST grounded to mains earth. This seems to be the best option from
>> among the available options.
>>
>> I've tried winding by hand and it was.... tedious. I may just lack the
>> patience, but spending 4 hours carefully winding a coil is not my idea of a
>> good time.
>>
>> > Your coil is running better with smaller toroid. Is this with all the
>> primary tapped?
>>
>> I had adjusted the tapping several turns in when using the small toroid,
>> based on some JavaTC calculations. It's hard to quantify how much longer
>> the arcs were, but I would not say more than 10%. I need a function
>> generator so that I can find the primary and secondary resonance
>> frequencies, and adjust my tuning with better accuracy. Perhaps after
>> Christmas....
>>
>> Joshua Thomas
>>
>>
>> On Tue, Nov 23, 2021 at 8:08 PM Chris Reeland <chrisreeland@xxxxxxxxx>
>> wrote:
>>
>>> Hi Joshua,
>>>
>>> You have not mentioned it...but I take it you corrected the NST centered
>>> tapped RF ground issue?
>>>
>>> Can not really help you on toroid construction...it took me several
>>> years to collect what I have in spun toroids on the used/NOS that I have
>>> acquired at decent prices.
>>> I can not ever justify buying direct brand new. They get extremely
>>> expensive when getting large. I have been lucky on most of the prices I
>>> have paid.
>>>
>>> On your secondary, I would suggest winding by hand... your secondary is
>>> not really big at all...it doesn't take as long as you would think...just a
>>> little patience.
>>>
>>> Your coil is running better with smaller toroid. Is this with all the
>>> primary tapped?
>>> If so, your bigger toroid does not work good because you are out of
>>> primary tuning available.
>>>
>>> Chris Reeland
>>> Ladd Illinois USA
>>>
>>> Sent from my Lenovo Tablet
>>>
>>> On Tue, Nov 23, 2021, 6:33 PM Joshua Thomas <joshuafthomas@xxxxxxxxx>
>>> wrote:
>>>
>>>> Thank you!
>>>>
>>>> My topload is covered with copper foil. The base is dryer tube. While
>>>> cheap, it is difficult to get a strongly smooth surface from it. I am
>>>> jealous of those who can get the smooth spun-aluminum toroids.
>>>>
>>>> On the topic, can anyone recommend a service that will create secondary
>>>> coils to specification? I am fairly bad at this and itâ??s one area I
>>>> would
>>>> be willing to spend a little money.
>>>>
>>>> Joshua Thomas
>>>>
>>>> On Tue, Nov 23, 2021 at 10:20 AM <pupman.com@xxxxxxxxxxxxxxxxxxx>
>>>> wrote:
>>>>
>>>> > Hi Joshua,
>>>> >
>>>> > The arcs look and sound great in this video. They grow and move vs.
>>>> > appear once and vanish. It does looks like there may be too many
>>>> > breakout/sharp points on the toroid though, and lots of energy is
>>>> being
>>>> > lost. A light wrap of foil might smooth things out enough to allow
>>>> > fewer, but longer and more developed streamers.
>>>> >
>>>> >
>>>> > On 11/21/2021 4:03 PM, Joshua Thomas wrote:
>>>> >
>>>> > <content trimmed>
>>>> > > These were used with 3 between each HV rail and RF ground. The caps
>>>> > caught
>>>> > > on fire after short use. You can see video of that event here:
>>>> > > https://youtube.com/shorts/Sx_lHwjR_bs?feature=share
>>>> > >
>>>> > > (I should likely have shut this down sooner)
>>>> > <content trimmed>
>>>> > _______________________________________________
>>>> > Tesla mailing list -- tcml@xxxxxxxxxxxxxxx
>>>> > To unsubscribe send an email to tcml-leave@xxxxxxxxxxxxxxx
>>>> >
>>>> --
>>>> Joshua Thomas
>>>>
>>>> My new email address is: joshuafthomas@xxxxxxxxx
>>>> Please update your information if you have not already done so.
>>>> _______________________________________________
>>>> Tesla mailing list -- tcml@xxxxxxxxxxxxxxx
>>>> To unsubscribe send an email to tcml-leave@xxxxxxxxxxxxxxx
>>>>
>>>
>>
>> --
>> Joshua Thomas
>>
>> My new email address is: joshuafthomas@xxxxxxxxx
>> Please update your information if you have not already done so.
>>
>
--
Joshua Thomas
My new email address is: joshuafthomas@xxxxxxxxx
Please update your information if you have not already done so.