I use a 10H (nominal) with 0.2 microfarad (nominal) and a 60K total bleeder
resistance on a negative filtered 3600 volt supply. I've found that an
empiric approach works well: as you increase the capacity towards resonance,
the regulation improves, but volts drop a bit. If you tune it the wrong side
of resonance, it will look capacitive.
I've always assumed that the you don't resonate the choke, since it would
then look purely resisitive, while what you are looking for is a high
inductive reactance at the ripple frequency in an attempt to maintain
constant current through the choke during each half cycle. This means
getting close to resonance, but still being fractionally HF of the ripple
frequency. This certainly seems to work in practice. As choke inductance
decreases with increasing current, there isn't a danger of actaully
resonating the choke, which could produce some interesting
voltages..........
73
Peter G3RZP
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