Re: [TCML] DC Coils

[Colin Heath <cohe@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi Carlos,

I would say Scott is correct in his statement. I would also consider your
inductive reactance of choke if you have one along with capacitive
reactance of smoothing cap. These could indeed limit your current, the
break rate test suggested by Scott will prove if this is the case.

Cheers,

Colin Heath






On 10/01/2012 20:23, "Scott Bogard" <sdbogard@xxxxxxxxx> wrote:

>Hi Carlos,
>     Having never built a DC coil you should probably ignore me, but if I
>had to guess I would say your doubler is limiting your current.  If you
>can
>vary your spark gap speed you can determine if this is the issue, if a
>faster break rate improves performance, current is not an issue, it was a
>calculation error, if it worsens performance, I would guess your current
>is
>being chocked by the doubler.  Again, probably best to ignore me, I've
>never built a DC coil, but you are correct for similar power levels
>results
>should be the same...
>
>Scott Bogard.
>
>On Tue, Jan 10, 2012 at 2:27 PM,
><lightningfor@xxxxxxxxxxxxxxxxxxxxxx>wrote:
>
>> Hi List,
>> I recently finished my first DC powered SGTC.
>> I was surprised by the size of capacitor needed to produce a given spark
>> length.
>> The information I used was gathered from Richie Burnetts web site, and I
>> am confident that I correctly understand the information
>> and formula's presented on the page.
>> My assumption was that I could choose a capacitor value, break rate, and
>> charging voltage the same as my large AC fed coils, and I would get a
>> similar performance in terms of spark length and power input.
>>
>> The result I got was quite different... I used 10kv DC input (so 20KV
>> after doubling) and a 0.07uF cap with breakrate of 180bps.
>> With my large AC coil I am getting 16ft arcs with 20kv AC RMS (so i
>>guess
>> 28kv peak), same cap and bps.
>> With the new DC coil, only getting 5ft arcs. Power draw is low, and RSG
>>is
>> clean running.
>> This all equates back correctly to the formulas in terms of BPS, input
>> volts and cap size giving a specific power draw....  I just don't
>> understand why my AC coil draws 3-4 times the power and produces 3 times
>> the arcs, when the cap  size and break rate is the same.
>> Sure, the peak voltage input is a bit higher, but not 3 times as high...
>>
>> Any comments...?
>>
>>
>> Carlos
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