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Re: [Amps] [ham_amplifiers] RE: The power of an oversized electrolytic c

To: "Roger (K8RI)" <k8ri@rogerhalstead.com>, <ham_amplifiers@yahoogroups.com>
Subject: Re: [Amps] [ham_amplifiers] RE: The power of an oversized electrolytic capacitor /howmuch PS filter C is enough?
From: Bill Fuqua <wlfuqu00@uky.edu>
Date: Fri, 11 May 2012 11:31:08 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
even active feedback systems have a damping factor.
If it is under damped it exhibits a resonant peak just before the
roll off frequency.
73
Bill wa4lav


At 02:46 AM 5/11/2012 -0400, Roger (K8RI) wrote:
>On 5/10/2012 3:21 PM, Carl wrote:
> >
> > Incorrect, it can be either active or passive.
>I think we are running into semantics,  but the way I see it(depending
>on how active feedback is defined)  if the math is done for either the
>flywheel or the caps they do see what I would call an active feedback.
>. In both cases when the energy storage device (which contains potential
>energy) sees less energy in the system it transfers energy into the
>system, or more correctly energy transfers or flows from the higher
>potential to the lower.
>
>Unless active feedback is defined as from an external device the system
>itself senses potential energy on both sides and attempts to equalize
>the energy by transferring from the higher potential to the lower and
>would stop if they became equal. In both cases the storage device is
>recharged when the system contains more energy than the storage device.
>
>73
>
>Roger (K8RI)
> > Carl
> > KM1H
> >
> >     ----- Original Message -----
> >     *From:* Al Kozakiewicz <mailto:akozak@hourglass.com>
> >     *To:* garyschafer@comcast.net <mailto:garyschafer@comcast.net> ;
> >     amps@contesting.com <mailto:amps@contesting.com>
> >     *Cc:* ham_amplifiers@yahoogroups.com
> >     <mailto:ham_amplifiers@yahoogroups.com>
> >     *Sent:* Thursday, May 10, 2012 11:46 AM
> >     *Subject:* [ham_amplifiers] RE: [Amps] The power of an oversized
> >     electrolytic capacitor /howmuch PS filter C is enough?
> >
> >     To continue the physical analogy, you're describing damping, not
> >     regulation. Adding mass to increase inertia may mimic the results
> >     of regulation, but only if the time interval of the measurement is
> >     relatively short.
> >
> >     For the purpose of the amplifier power supply discussion, I get
> >     the point. But regulation is an active process, not passive, and
> >     requires feedback.
> >
> >     Al
> >     AB2ZY
> >
> >     ________________________________________
> >     From: Gary Schafer [garyschafer@comcast.net
> >     <mailto:garyschafer@comcast.net>]
> >     Sent: Thursday, May 10, 2012 11:21 AM
> >     To: Al Kozakiewicz; amps@contesting.com <mailto:amps%40contesting.com>
> >     Cc: ham_amplifiers@yahoogroups.com
> >     <mailto:ham_amplifiers%40yahoogroups.com>
> >     Subject: RE: [Amps] The power of an oversized electrolytic
> >     capacitor /how much PS filter C is enough?
> >
> >     Think about this: if you place a resistor between the transformer
> >     and the
> >     filter capacitor your dynamic regulation will deteriorate. Thus
> >     the need for
> >     low resistance transformer windings and heavy primary lines. This
> >     is just as
> >     much "regulation" as is an active regulator, although not with the
> >     same
> >     precision.
> >
> >     A flywheel on an engine does provide dynamic regulation as well.
> >     It keeps
> >     sudden loads from dragging the rpm down instantaneously as well as
> >     smoothing
> >     the "ripple" of the firing cylinders.
> >
> >     73
> >     Gary K4FMX
> >
> >     > -----Original Message-----
> >     > From: amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>
> >     [mailto:amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>]
> >     > On Behalf Of Al Kozakiewicz
> >     > Sent: Thursday, May 10, 2012 9:29 AM
> >     > To: amps@contesting.com <mailto:amps%40contesting.com>
> >     > Cc: ham_amplifiers@yahoogroups.com
> >     <mailto:ham_amplifiers%40yahoogroups.com>
> >     > Subject: Re: [Amps] The power of an oversized electrolytic capacitor
> >     > /how much PS filter C is enough?
> >     >
> >     > Although I understand the point being made, filter capacitors,
> >     no matter
> >     > how large, do not provide "regulation" any more than a big flywheel
> >     > takes the place of a governor on an engine. Regulation requires
> >     active
> >     > circuitry and feedback.
> >     >
> >     > OK, back to nuclear weapons design.
> >     >
> >     > Al
> >     > AB2ZY
> >     >
> >     > ________________________________________
> >     > From: amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>
> >     [amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>] On
> >     > Behalf Of Leigh Turner [invertech@frontierisp.net.au
> >     <mailto:invertech%40frontierisp.net.au>]
> >     > Sent: Thursday, May 10, 2012 7:19 AM
> >     > To: 'Jim Thomson'; amps@contesting.com
> >     <mailto:amps%40contesting.com>
> >     > Cc: ham_amplifiers@yahoogroups.com
> >     <mailto:ham_amplifiers%40yahoogroups.com>
> >     > Subject: Re: [Amps] The power of an oversized electrolytic
> >     capacitor /
> >     > how much PS filter C is enough?
> >     >
> >     > Hi Jim,
> >     >
> >     > There are two aspects to consider here; the static and dynamic
> >     voltage
> >     > regulation, and the amount of ripple on the B+ plate supply.
> >     >
> >     > In CW and SSB amplifier service the keyed and syllabic
> >     fluctuation of
> >     > load
> >     > defines the requisite dynamic regulation capability of the HV power
> >     > supply.
> >     > Achieving static and dynamic regulation under 5 percent would be
> >     good
> >     > design
> >     > practice. As for rms ripple voltage, a target of less than 2 to 5
> >     > percent of
> >     > the DC supply voltage under full load current would be
> >     considered good
> >     > engineering practice.
> >     >
> >     > A large energy storage capacitance on the HV rail makes sense
> >     from the
> >     > point
> >     > of view the amplifier load current requirements have a large
> >     peak-to-
> >     > average
> >     > ratio in SSB service. A stiff B+ voltage also helps with
> >     minimising IMD.
> >     >
> >     > For common 3 kV @ 1A amplifier power supplies, i.e. a load
> >     resistance of
> >     > circa 3000 Ohms, a reservoir capacitance of about 60 uF would be
> >     > sufficient
> >     > to yield the above respectable regulation and ripple objectives. One
> >     > might
> >     > double the filter capacitance to circa 100 uF for good measure; but
> >     > going
> >     > beyond that amount of capacitance would be a futile exercise in
> >     > diminished
> >     > returns.
> >     >
> >     > Now your 7 kV B+ supply corresponds to a PS load resistance of circa
> >     > 7000
> >     > Ohms, so there is an associated relaxation in the capacitance
> >     required
> >     > to
> >     > meet a given percentage ripple voltage objective.
> >     >
> >     > The tolerable ripple level superimposed on the HV plate supply above
> >     > which
> >     > incidental AM hum sidebands appear on the radiated signal is an
> >     > interesting
> >     > question; the anecdotal experience of Rich's friend with only 2
> >     uF of
> >     > filter
> >     > capacitance suggests there's a large tolerance to ripple on the
> >     plate
> >     > supply
> >     > with the tube and tank circuit exhibiting a good PSRR.
> >     >
> >     > We can note the amplifier in question here uses a 4-1000
> >     tetrode, and
> >     > that
> >     > such tubes exhibit a plate current virtually independent of plate
> >     > voltage,
> >     > i.e. tetrodes are a constant current device. Such a
> >     characteristic would
> >     > make it more immune to ripple and noise on the B+ plate supply.
> >     >
> >     > Leigh
> >     > VK5KLT
> >     >
> >     >
> >     > -----Original Message-----
> >     > From: amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>
> >     [mailto:amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>]
> >     > On
> >     > Behalf Of Jim Thomson
> >     > Sent: Tuesday, 8 May 2012 5:19 PM
> >     > To: amps@contesting.com <mailto:amps%40contesting.com>
> >     > Subject: [Amps] The power of an oversized electrolytic capacitor /
> >     >
> >     > Date: Sat, 5 May 2012 20:59:29 +0930
> >     > From: "Leigh Turner" <invertech@frontierisp.net.au
> >     <mailto:invertech%40frontierisp.net.au>>
> >     > Subject: Re: [Amps] The power of an oversized electrolytic
> >     capacitor /
> >     > overkill
> >     >
> >     >
> >     > I agree Rob; a fraction of that massive HV PS capacitance would
> >     create
> >     > an
> >     > unperceivable difference in the Tx performance and signal at a
> >     distant
> >     > Rx
> >     > station :-)
> >     >
> >     > Leigh
> >     > VK5KLT
> >     >
> >     > ### Leigh, how many uF in your opinion, do you suggest I use on
> >     a 7.7 kv
> >     > No
> >     > load B+ supply.
> >     > What is the bare minimum I could get away with. I'm being
> >     serious here.
> >     > Rich Measures has a friend with a 4-1000 amp...and he only uses
> >     2 uf for
> >     > a
> >     > filter cap...and No choke anywhere. Nobody hears any hum.
> >     >
> >     > On a similar note, a friend was on one night, toggling between
> >     his SB-
> >     > 220
> >     > and his Alpha 9500. Nobody could tell the difference between the
> >     1200w
> >     > of
> >     > the SB-220.....and the 1500w of the Alpha 9500.
> >     >
> >     >
> >     > -----Original Message-----
> >     > From: amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>
> >     [mailto:amps-bounces@contesting.com
> >     <mailto:amps-bounces%40contesting.com>]
> >     > On
> >     > Behalf Of Rob Atkinson
> >     > Sent: Saturday, 5 May 2012 8:53 PM
> >     > To: Jim Thomson
> >     > Cc: amps@contesting.com <mailto:amps%40contesting.com>
> >     > Subject: Re: [Amps] The power of an oversized electrolytic capacitor
> >     >
> >     > 832 uF at 7.7 KV. No offense, but that's a waste of capacitors.
> >     >
> >     > Rob
> >     > K5UJ
> >     >
> >     > On Fri, May 4, 2012 at 9:28 AM, Jim Thomson <jim.thom@telus.net
> >     <mailto:jim.thom%40telus.net>> wrote:
> >     >
> >     > > ### BTW, My latest creation uses 24 x 10,000 uf @ 450 vdc
> >     caps, all
> >     > in
> >     > > series... and charged up to 7700 vdc. That's one bank. I built
> >     a 2nd
> >     > > identical bank of 24, and parallel the 2 x banks together...
> >     onto a
> >     > common
> >     > > buss....
> >     >
> >     > ### I got them for dirt cheap. There is No way I would build
> >     something
> >     > like this by paying full price for new caps. I wouldn't buy a
> >     brand new
> >     > vac
> >     > cap from Jenning's either, they are cost prohibitive. But I have
> >     > managed to
> >     > buy surplus, nib, sealed in the box, Jennings ceramic vac caps. They
> >     > come
> >     > encased in a metal foil bag which has been vac sealed. You poke
> >     a pen
> >     > knife
> >     > into it, and whoosh, the air rushes into the bag. Once bag is
> >     removed,
> >     > then
> >     > you unseal the box...and the new vac cap is inside a box, lined with
> >     > foam
> >     > rubber on all 6 x sides.
> >     >
> >     > later... Jim VE7RF
> >     >
> >     >
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