Message-ID: <576D2454.7000306@posteo.de>
Date: Fri, 24 Jun 2016 14:15:16 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <579355A36AEE9D4FA555C45D556003AB53C65519@servigilant.vigilant.local> <576CEFAF.4040701@posteo.de> <3f5412f0-8fee-5fa9-fd0e-6e7d6d3071f1@kabelmail.de>
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Subject: Re: LF: RE: Re: Cumiana OOS
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Hi Tom,

I doubt that these voltage transformers will handle 1 kW. Actually their 
power is rated at a few 10W at 50 Hz. You would then suggest to use them 
in a non-resonant antenna matching? I am also quite sure that they will 
not manage 2970 Hz at a reasonable voltage. Another thing is their 
self-resonance frequency or internal capacity. I have tried various 
methods, also ring core mains transformers which gave the 2nd best 
results in my tests.

What i'm starting next is a multi-layer 'air-cored' coil with stacked 
windings, as announced. The 250 mm PVC tube, 2 kg of 0.4mm and the 
Kapton tape is already here. I will need 6 km of wire!! The goal is 40 
kV at 2970 Hz :-)

73, Stefan

Am 24.06.2016 11:55, schrieb DK1IS:
> Am 24.06.2016 um 10:30 schrieb DK7FC:
>> Ignition coils, well, they may handle the voltage but i think the 
>> winding will become to warm at 30 mA 24/7. But the main problem would 
>> be that i need a certain inductance because it is a resonated 
>> circuit. So i need an adjustable air gap into the ferrite material, 
>> like i have in my arrangement. Also, the ignition coil may generate 
>> (and temporary hold) 20 kV but i don't assume that it can generate 
>> that voltage at 2.97 kHz but just on higher frequencies. It is the 
>> same with the old TV transformers (LOPT). They may generate 3 kV but 
>> not at 2.97 kHz. There, they would saturate. Of course i already 
>> checked that a long time ago :-)
>>
>>
> Hi Stefan,
> just another idea: what about old voltage transformers 
> (Spannungswandler) from your local utility company, at least for a 
> test? The 20-kV-versions should have an insulation test voltage of 50 
> kV against ground and secondary winding, the nominal secondary voltage 
> is 100 V at 50 Hz. They have high-quality iron cores and should 
> core-wise be able to handle more than 1 kW at 3 kHz. Following your 
> own transductor idea, you could superimpose a DC component in series 
> to the AC signal on the secondary (now primary) winding to tune the 
> inductivity. Weak points could be the current capability especially of 
> the primary (now secondary) windig and its resonance frequency - this 
> has just to be tested.
>
> 73 es gl,
> Tom, DK1IS
>
>