With respect, this is out of the dark ages.
Look for www.duncanamps.com ( I think).
There you will find a computer programme that permits you to model any power
supply you can visualise and check regulation (static and dynamic), ripple %
etc etc etc.
73
Barry
end
Barry Kirkwood PhD ZL1DD
Signal Hill Homestay
66 Cory Road
Palm Beach
Waiheke Island 1240
NEW ZEALAND
ph/fax 64-9-372-5161
www.waiheke.co.nz/signal.htm
----- Original Message -----
From: "Will Matney" <craxd1@ezwv.com>
To: <amps@contesting.com>
Sent: Wednesday, August 18, 2004 2:15 PM
Subject: [Amps] Filtering capacitor in a HV PS
> Geo,
> Here's pretty much what I know on the subject going from the
> manufacturers point of view. Taking both sides from the component
> manufacturer and the OEM's. First, keep in mind that a choke input
> really shouldn't be used on SSB service by what I was taught, only a C
> input. In my opinion, I would use a C with a capacitance just as high as
> I would for a C input. The reason being is the changing inductance of L
> due to the varying DC load will allow more AC product to be at the
> output of the choke. In a C input, this would be a lesser value as C1
> would deal with the AC first before the choke. Now the formula which
> Rich gave is correct in determining C for the capacitance value (70,000
> / RL). The voltage rating however of X2 is something I don't quite agree
> with. This is due to some papers written in "Passive Component" magazine
> by the capacitor manufacturers. According to them, the dialectic is
> designed around a certain voltage for the capacitance needed. They said
> that by not using a capacitor close to its voltage value, the
> capacitance itself can change over time. Needless to say, this is very
> unwanted. I will have to try and dig this info up if I still have it as
> this is a printed magazine I get bi-monthly. A lot of this finds file
> 13. It could possibly be in an archive somehow at their website, I'm not
> sure. Now, I'm strongly thinking that one would be better off using a C
> with a voltage rating of only 1-1/2 X voltage. As Rich points out, the
> actual failure voltage is considerably more than the rating itself
> anyhow. I can also state from experience that a cap bank of two (2) 450
> Vdc caps will withstand a +900 Vdc source on them for years too as I
> have seen it time and time again. I have actually seen + 1000 Vdc on
> only this same 900 Vdc setup without any pre-mature failure. I myself
> use 6 X 450 Vdc caps for 2500 Vdc with no premature failures. All
> electrolytics will fail over time as they age and the dialectic gives
> out. From what I've read and from general experience of 22+ years of
> making amps, I would have to concur with the capacitor manufacturers.
> Hopefully, I might locate this article, but if not, one might find
> something on the net about it.
>
> Will Matney
>
> Interesting information Will, Can you tell me what C is typical for a
choke input?
>
> Geo W7LFD
>
>
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