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RE: [TCML] Ballasting my Homemade Transformer.



Jim
The cross sectional area decides how many primary turns you will need to get
a decent flux created. Once you have enough flux created in that particular
core you will then know how many turns your primary must have. Then you can
then decide on the turns ratio between the primary and secondary, and thus
the final output voltage.
The bigger the core area the less turns you will need on the primary. Which
means less room taken up, so more secondary turns can be added.
There is also the question of saturation. A small core will saturate sooner
if the primary current is too high. The primary current needs to be highish
though if you want a decent current in the secondary. Decent current =
decent sparks. So everything boils down to the core size ultimately. Size
does matter!

Regards

Phil
www.follytowers.co.uk/tesla

     




-----Original Message-----
From: Jim Mora [mailto:wavetuner@xxxxxxxxx] 
Sent: 05 May 2009 05:53
To: 'Tesla Coil Mailing List'
Subject: RE: [TCML] Ballasting my Homemade Transformer.

Hi Bart,

Great shot! That almost says it all. Clearly, this opens the winding window
to get the copper in there! Stacking the E cores affects the current by a
mathematical function, yes? This discussion simplifies the math challenged
such as myself :-^)

It seems weird to me that the cross section area is mostly discussed in this
vein. If I knew the answer to this, the simplified, pseudo functions of core
geometry would be clear to me.

Thanks Much,
Jim Mora

-----Original Message-----
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of bartb
Sent: Monday, May 04, 2009 6:40 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] Ballasting my Homemade Transformer.

Hi Jim,

I should show an NST 12/60 broken down:
http://www.classictesla.com/photos/nstrepair/Image4.jpg

There you can see the two E cores.

Take care,
Bart


bartb wrote:
> Hi Jim,
>
> Sure. For example a Franceformer 12/60 NST uses 2 E-cores in just this 
> fashion. The primary is located in the center leg and center to the E 
> cores. There is a secondary on the same center leg to each side of the 
> primary (with of course shunts between the primary and secondaries top 
> and bottom of the center leg).
>
> As Phil mentioned, it may not make the most ideal transformer and some 
> slight leakage if the cores do not butt together nice and flat, but 
> that's not a big deal if you used the cores for a high voltage 
> transformer. If the ends are not flat, then you'll certainly want to 
> ensure it's potted to prevent buzzing. BTW, if you use a potting 
> compound like wax or other that gets relatively hard, when the potting 
> material is about half cured, energize the transformer (this will pull 
> the two cores together nice and tight and any potting material that 
> had seeped between the two cores is squeezed tight providing a nice 
> packed seal between the two cores). Makes for a silent running 
> transformer. I energize the tranny two or three times for about 5 
> seconds at different stages during the curing process (while the wax 
> or whatever is still very soft).
>
> Take care,
> Bart
>
> Jim Mora wrote:
>> Hello,
>>
>> Good reference material! Since we are on the topic, I was wondering 
>> if (2) E
>> cores could be used (opposing each other) without the I core. This would
>> double the winding window and still allow for some leakage spacing. (4)
>> would double the core size yet again (two deep). I have a number of 
>> beefy
>> transformers from an inverter cabinet.
>>
>> My goal is to make a seriously stiff filament transformer, So in 
>> review: 150
>> -200 turns for 240, wired sized for current in and out, 2.25-2.5 
>> inch^2 for
>> each kwatt. Good stuff!
>>
>> Jim Mora
>> Anyone see issues with using dual inverted stacked E cores?
>> -----Original Message-----
>> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On 
>> Behalf
>> Of David Rieben
>> Sent: Sunday, May 03, 2009 6:37 AM
>> To: Tesla Coil Mailing List
>> Subject: Re: [TCML] Ballasting my Homemade Transformer.
>>
>> Hi all,
>>
>> I took the core of a gutted defunct x-ray transformer (I
>> seem to burn them out a lot ;^(), and rewound each
>> "leg" with 105 turns of #8 THNN building wire,>>>
>> <snip>
>>
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>>   
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