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I built a 4 X 7.5KV = 240ma Jefferson coil that was quite awesome. Don't
really need 15kv NSTs for amazing results.
On 2/20/2015 9:02 PM, Gary Lau wrote:
> The only reason to have transformers be identical is a matter of
> aesthetics. As long as the output voltage is remotely similar, one can mix
> France, Jefferson, whatever, flavors of NST's, if the phasing is correct,
> and you'll know immediately if it's wrong. It's _nice_ to have them
> identical but functionally unnecessary.
>
>> There would be a lot more changes than just caps and gaps.
>
> I would like to amplify the above point. Assuming you want to do
> everything needed to extract the maximum arc length from the additional
> power at your disposal, repeat over and over - Bigger is Better. You'll
> want a larger top load, and you'll want a taller secondary to space the top
> load farther from the primary to avoid strikes to it. The larger top load
> and secondary will require a significantly larger primary, not just another
> couple of turns. I ended up building a 2-layer primary to keep
> the dimensions sane. Higher inductances and lower frequencies are all good!
>
> Also, a 15/120 power supply is probably going to push the limits of what a
> static gap can handle. You didn't mention what you're planning for a gap
> but you might wish to consider a rotary. I highly recommend the propeller
> gap configuration - http://www.laushaus.com/tesla/sync_gap.htm If you're
> thinking about a synchronous rotary, the capacitor size needs to be much
> higher than for a static gap, and will require comparably more primary
> inductance.
>
> And, a 15/120 power supply is going to pull a LOT of juice from the wall -
> you'll want to make sure you have an adequate PFC capacitor to minimize
> current draw. My single 15/60 pulls in excess of 20A with a sync rotary
> and 240uF of PFC caps.
>
> Bottom line - you should plan from day 1 what the final configuration is
> going to be - you'll not be able to go back and forth with 1 or 2 NST's.
>
> Regards, Gary Lau
> MA, USA
>
>
>
>
>
> On Fri, Feb 20, 2015 at 1:32 PM, Timothy Gilmore <tdg8934@xxxxxxxxx> wrote:
>
>> Great videos on Phasing (both parts 1 and 2). I will watch those again when
>> ready to set up.
>>
>> On Fri, Feb 20, 2015 at 9:36 AM, John Paul Grippa <pupman@xxxxxxxxxxxx>
>> wrote:
>>
>>> There is a great video from the Geek Group on YouTube that explains how
>>> this works extremely well. It will also give some good tips on how to
>>> ensure proper phasing. Check it out!
>>> https://www.youtube.com/watch?v=KSlQjw9OPG4
>>>
>>>
>>>> Date: Fri, 20 Feb 2015 08:26:17 -0600
>>>> From: tdg8934@xxxxxxxxx
>>>> To: tesla@xxxxxxxxxx
>>>> Subject: [TCML] Dual identical FRANCE neon sign transformers (15000v
>>> 60mA each) in parallel
>>>>
>>>> I currently have a France NST at 15kv 60mA and built a nice jacobs
>> ladder
>>>> with it. Yesterday on eBay I found what looks to be identical model NST
>>> for
>>>> a good price (no GFI). From what I have read about NST phasing, having
>>>> identical NSTs don't require testing the HV outputs and I should be
>> able
>>> to
>>>> connect them up in parallel identically using the same sides. What a
>>> jacobs
>>>> ladder at 120mA would be! Anyway I'm assuming that I should start
>>> building
>>>> my tesla coil with 1 NST and when it works add the next NST in parallel
>>> and
>>>> double the capacitors and change the tap on the primary. Does this
>> sound
>>>> like all I would need to do?
>>>>
>>>> Thanks - Tim
>>>> _______________________________________________
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>>>
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