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From: Bill Sloman <bill.sloman@ieee.org>
Newsgroups: sci.electronics.design
Subject: Re: CCFL transformer
Date: Fri, 26 Apr 2024 12:34:29 +1000
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On 26/04/2024 7:40 am, John Larkin wrote:
> On Thu, 25 Apr 2024 21:10:14 -0000 (UTC), Jasen Betts
> <usenet@revmaps.no-ip.org> wrote:
> 
>> On 2024-04-25, legg <legg@nospam.magma.ca> wrote:
>>> On Wed, 24 Apr 2024 01:57:36 +0200, Klaus Vestergaard Kragelund
>>> <klauskvik@hotmail.com> wrote:
>>>
>>>> Hi
>>>>
>>>> I need a low distributed capacitance winding transformer, for a HV
>>>> stepup function (3.5kV)
>>>>
>>>> I am zeroing in on similar concept as CCFL transformers with
>>>> sectionalized bobbin.
>>>>
>>>> For example:
>>>>
>>>> https://www.coilcraft.com/en-us/products/transformers/power-transformers/ccfl-transformers/fl/
>>>>
>>>> Possibly using Triple Insulated Wire to create some distance between the
>>>> individual turns.
>>>>
>>>> Not many sells CCFLs these days.
>>>>
>>>> Guess I will keep it alive....
>>>>
>>>> Regards
>>>>
>>>> Klaus
>>>
>>> Stress between turns is limited by v/n limit of core. It's layer
>>> stress and section stress that you have to deal with.
>>> That's what the multisection bobbin and pancake windings do.
>>>
>>> If the CCFL transformer will allow only 1600V, imagine the
>>> precautions required for 3x that stress. I'm not sure you
>>> can avoid vacuum impregnation / potting in anything 'small'.
>>
>> I see trandformers claimed for 15kV with 6 sections of loose wound
>> magnet wire.  This is however Chinese consumer marketing kilovolts.
>>
>> https://www.aliexpress.com/item/1005002225061453.html
>>
>> Given the ~2mm spark gap it suggests something less than 15kV
> 
> How dinky. This one is 400 KV.
> 
> https://www.amazon.com/AEDIKO-Voltage-Generator-400000V-Transformer/dp/B09L18GG2Z

If you believe that, you will believe anything. This looks like the 
usual bankrupt stock retailer - they get stuff they don't know much 
about from businesses that have gone bust, and try to sell it.

-- 
Bill Sloman, Sydney