Types of flybacks for HV/HF?

[clone477]

I'm looking for some help on understanding the limits of flybacks.  Im looking for a HV flyback and wondering the highest frequency they can operate at?  Ideally I am looking for 200khz-300khz but I really do not know the upper limit for these.  Ir seems standard frequency is 20khz?  Can anyone provide some basics on the limits or provide a source where I can learn more about this?  Thank you guys.

[Egg]

I think a standard tv flyback can be driven with anywhere around 15-300khz. I don't know much about the upper frequency limit but you shouldnt drive ferrite core transformers with very low frequencies.

[clone477]

Thanks for the response, how would you confirm?  Would you be able to see a clean ac signal on the output get distorted on the scope when the max frequency of the core is reached?

[Egg]

I don’t think the “max frequency” is something you should worry about. If you are trying to use it as a arc source 15-300khz is generally good.
As to confirming if the frequency is unsuitable, too low frequencies will likely short the primary coil.

[alan sailer]

I don't have any hard and fast limits on HV flyback frequency response. But I've bought a few dozen vintage AC flybacks
and the operating frequencies are in the 35-100kHz range.  I have few moden HV transformer from Chirk that runs at about 25kHz.

I messing around right now with an air core AC HV coil designed by another engineer and I have it operating at 120kHz at
resonance. Other than tesla coils this is the highest I've seen.

Cheers.

[davekni]

Im looking for a HV flyback and wondering the highest frequency they can operate at?  Ideally I am looking for 200khz-300khz but I really do not know the upper limit for these.

Most HV flyback transformers have internal diodes and output DC.  For those, I can't think of any reason to run them far above design frequency.  Commonly-available ones are from old broadcast TV sets, designed for 15.75kHz or 15.625kHz to match horizontal scan frequency.  With sine-wave drive, can run fine to 30kHz or so.  Flyback transformers for CRT computer monitors used higher frequencies corresponding to the monitor's horizontal deflection rate.  (Though some monitors separated HV generation from horizontal scan frequency.)
AC flyback transformers (ones without internal diodes) are quite rare, but a few are available.  Upper frequency is limited by resonant frequency of HV winding, probably under 100kHz.  It is possible to drive them at higher frequency, but output voltage will be low.