[Amps] Power factor and choke vs resonant-choke input supplies

[Barrie Smith]

Peter:

Resonant-chokes may be placed in the negative lead?

Also, could you elaborate on the "close to it" resonance?

I have a largish power supply, using a Peter Dahl resonant-choke/capacitor
combination,  that has never worked properly.  I'd like to improve or
rebuild the power supply so that it did work properly.

73, Barrie, W7ALW


----- Original Message ----- 
From: "Peter Chadwick" <g3rzp at g3rzp.wanadoo.co.uk>
To: "Borislav Trifonov" <bdt at shaw.ca>; "Harold Mandel"
<hmandel at barantelecom.com>
Cc: <amps at contesting.com>
Sent: Thursday, May 10, 2007 10:34 AM
Subject: Re: [Amps] Power factor and choke vs resonant-choke input supplies


> Why are you particularly worried abuot the power factor?
> Some simulations a colleague did some years back suggests that in fact,
the choke shouldn't be resonant, but very close to it, such that the choke
looks like a very much bigger inductance rather than a straight resistance
at the ripple frequency. This is done for minimum load, as the choke
inductance will decrease somewhat as the load increases. That's how I very
succesfully use tuned choke input: in addition, I filter in the negative
lead, so you don't need to worry about the case to innards insulation n the
capacitor when it's reasonable size metal cased oil cap. Incidentally, the
chokes were always obtained by a process f scrounging - I've never bought
one yet! That includes a massive 10H 1 Amp one set aside for a project....
> I believe Tom, W8JI, has some hair raising tales about his first attempts
at resonant choke input supplies....
> 73
> Peter G3RZP
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