[Amps] Power factor and choke vs resonant-choke input supplies
bdt at shaw.ca
Thu May 10 09:01:07 EDT 2007
I intend to use it for low power, low voltage stuff. :) I asked here
since it's the place most people would be familiar with resonant chokes.
My main question remains: that of power factor.
Harold Mandel wrote:
> Dear Boris,
> The closer you look at power supply chokes, the worse the situation
> Firstly, the sheer weight of copper and iron is daunting.
> Secondly, the cost of copper approaching that of gold nowadays
> makes winding them a mortgage-qualifying event.
> Thirdly, the total amperage through them, considering the peak
> talk power and the bleeder resistor load, etcetera, etcetera, means
> for the average 3KW amplifier a hunk of metal equaling, if not
> surpassing the weight of the anode iron. Where ya gonna put it?
> Resonant chokes are not a simple deal either. Their resonant
> frequency is determined by their inductance and the paralleled
> capacitance, and that's the rub, because you just can't pick a cap
> off the shelf and hope it will work with a particular choke to achieve
> resonance at let's say 120 Hertz right off the bat.
> A manufacturer of commercial chokes talked with me about this. His
> suggestion was to design the choke/cap circuit, do the math for
> 120Hz resonance, and find a suitable cap at the exact value, oil-filled,
> plenty of overhead voltage capability and buy a crate full so when the
> choke is wound the winder can use the sample capacitor as the test
> jig to measure 120Hz resonance, and there will be exact spares on
> hand when the caps periodically burn out.
> All this for right around 1400 bucks for a two-amp, 9 Henry, 6KV
> resonant choke that would tip the scales at 845 pounds, delivered.
> I went to the C-input design.
> Hal Mandel
> I don't like the need for big chokes.
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