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
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