[TCML] Dr. Resonance inductors - 1/16th of an inch?

DC Cox resonance at wildblue.net
Fri Mar 6 09:18:04 MST 2009

```Steve --- you are absolutely right.

I have a crate that measures approx 72" x 36" x 24" H. which contains 40 of
these air core units.  I can't imagine this crate containing "50 houses".
Not in my medium size warehouse.

Dr. Resonance

On Fri, Mar 6, 2009 at 2:02 AM, Stephen Hiscock <stephenhiscock at yahoo.com>wrote:

> I think people might be possibly confusing the way they calculate the
> inductance of a coil.
>
> Large inductances are NOT hard to make - and certainly don't need to be as
> big as a house!!!!!
> or are we talking about stacking large amounts of these?
>
> I believe inductance is calculated by
> L= (d^2 * n^2)/(18*d+40*l)  (MicroHenries)
> where:
> L is inductance in micro Henrys,
> d is coil diameter in inches,
> l  is coil length in inches, and
> n is number of turns.
>
> so 25 inch diameter
> length of 50 inches
> and number of turns 2000
> = 1,020,000uH
> or 1.02 HENRIES
> Which is physically quite big! - but so are tesla coils and no-one seems to
> care?!?!
>
> but if wound fairly compact they can be made smaller with more turms
>
> eg
> 15 inch diameter
> and 15 inch length
> and 2000 turns gives
> 1,03 Henries
> (but I guess this might not handle high voltage)
>
> or 5 x 5 x 3500 turns = 1 Henry
>
> or 1x 1 x 8000 turns = 1 Henry!!!
> or 1/16th x 1/16th x 30000 turns = 1 Henry!!!!
> does turns per volt matter?? -
>
> I'm sure you get the point  - it depends on the dimensions and number of
> turns - with the diameter or turns being the dominant factors
> These numbers are NOT unusual -
> Perhaps people are confusing Capacitance for inductance???
> Now a 1 farad HIGH voltage capacitor would be quite large
>
> Regards
> Stephen
>
>
> Jim Mora wrote:
>
>> Hi All,
>>
>> It may be reasonable to assume that DC is confusing the 1mh air core choke
>> or he has a hugh Marx generator much taller than his building!
>>
>> Respectfully,
>> Jim Mora
>>
>> -----Original Message-----
>> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On
>> Behalf
>> Of Lau, Gary
>> Sent: Thursday, March 05, 2009 4:28 PM
>> To: Tesla Coil Mailing List
>> Subject: RE: [TCML] Dr. Resonance inductors
>>
>> Assuming a single-layer close-wound air core solenoid made from 30AWG
>> magnet
>> wire, a 1H inductor would be huge!  12.33" diameter x 36" long.
>>
>> I'll preface this by stating that I know very little about Marx generator
>> construction.  But it seems to me that the inductors would need to support
>> only the charging current of the caps by the PSU.  So if you're using a
>> rectified 15/30 NST, 30 mA is the most that the inductors would need to
>> support.  The discharge current of the erected circuit travels only
>> through
>> the gaps and caps - not the inductors.
>>
>>  The inductance requirement in a Marx generator is less clear, but as the
>> erected pulse duration of a Marx generator is extremely brief, 1H seems
>> WAY
>> larger than necessary.  A little bit of Googling finds typical inductance
>> values between .5-1.0 milliHenry.
>>
>> Regards, Gary Lau
>> MA, USA
>>
>>
>>
>>> -----Original Message-----
>>> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On
>>> Behalf Of Quarkster
>>> Sent: Thursday, March 05, 2009 5:14 PM
>>> To: Tesla Coil Mailing List
>>> Subject: Re: [TCML] Dr. Resonance inductors
>>>
>>> DC -
>>>
>>> You are not implying that your stock of 1H air-core inductors are stored
>>>
>>>
>> outdoors
>>
>>
>>> under a snow bank, are you??
>>>
>>> Would it be possible for one of your employees at Resonance Research
>>>
>>>
>> to provide
>>
>>
>>> a photo of one of these very interesting inductors so we all don't have
>>> to
>>>
>>>
>> wait for
>>
>>
>>> spring to arrive in Wisconsin?
>>>
>>> In the meantime (since these inductors have generated so much interest &
>>> discussion), could you just share some details of their design &
>>>
>>>
>> construction?
>>
>>
>>> Like -
>>> 1. Air insulated, or oil insulated?
>>> 2. Approximate physical dimensions?
>>> 3. RMS current rating?
>>> 4. Approximate weight?
>>>
>>> just
>>>
>>>
>> the top-
>>
>>
>>> level specifications you would provide to a prospective customer.
>>>
>>> Regards,
>>> Herr Zapp
>>>
>>>
>>> --- On Thu, 3/5/09, DC Cox <resonance at wildblue.net> wrote:
>>>
>>> From: DC Cox <resonance at wildblue.net>
>>> Subject: Re: [TCML] Dr. Resonance inductors
>>> To: "Tesla Coil Mailing List" <tesla at pupman.com>
>>> Date: Thursday, March 5, 2009, 9:20 AM
>>>
>>> I can't post a photo until I return to WI shop as they are in frozen
>>>
>>>
>> tundra
>>
>>
>>> Wisconsin.  I'm in Tucson for the winter.
>>>
>>> I've used them in 3 Marx gens so far, and they work excellent.  Inductors
>>> and resistors work the same in this circuit.
>>>
>>> DC
>>>
>>>
>>>
>>>
>>>
>>> On Wed, Mar 4, 2009 at 7:26 PM, Jim Mora <wavetuner at gmail.com> wrote:
>>>
>>>
>>>
>>>> Hi Dc, List,
>>>>
>>>>
>>>>
>>>> I would very much like to see the construction of a 1H air core
>>>>
>>>>
>>> inductor.
>>
>>
>>> I
>>>
>>>
>>>> plan to build a Marx Generator in the future. I know there are
>>>>
>>>>
>>
>>
>>> to
>>>> using an inductor rather than a resistor in the stages besides prices.
>>>>
>>>>
>>> Can
>>
>>
>>> you post a picture and comment on the construction?
>>>>
>>>>
>>>>
>>>> Thanks,
>>>>
>>>>
>>>>
>>>> Jim Mora
>>>>
>>>> _______________________________________________
>>>> Tesla mailing list
>>>> Tesla at www.pupman.com
>>>> http://www.pupman.com/mailman/listinfo/tesla
>>>>
>>>>
>>>>
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>>>
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