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I keep finding anomalies? with? PSUD-2.? Like when a plane jane? L-C?? filter is used, the +? and? -? peak V? across the? choke is beyond? sky high... like? 17 +? KV? !

I tried every possible LC config? you can think of, and still get? sky high? V across the choke.?? Also tried increasing the input Z of the plate xfmr, and increasing the

ESR of the filter caps, lowering the B+, and also? varying the steady state load on the supply.? Using the stepped load feature of PSUD-2, like idle current to normal full

bore plate current.... or vice versa,? still bad results.?

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Another? issue is when a glitch resistor is used, like typ a HV fuse inserted? in the B+? line, followed? by the? glitch resistor,? PSUD?? wont allow? you to insert just the resistor.

It wants to see a RC network tacked onto the existing? filter.?? To get around that,? I used? .01 uf.... which is the smallest value? PSUD-2? allows to be used.??? The idea being the

.01 uf is the? bypass cap at the cold end of the plate choke.???? OK, now the problems start.? PSUD-2? P-P? ripple? goes nuts, and very ..spiky.?? Once the C2? cap is increased to

.03 uf, then the anomalies and spikes? vanish.

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Also noted is that a C-L network or a? C-R network does not improve the p-p? ripple at all,? none.?? P-P ripple is the same as just a plane C filter.

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I was experimenting with both a C-L-C and also a C-R-C? filter setup.?? But once the additional?? glitch R? +? bypass cap was added to the mix,? ripple results are spiky.

The bypass cap value has to be increased to... fool the? PSUD-2? software.?

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If a HV fuse used, followed by a glitch resistor....and? B+? arcs to chassis, or the grounded grid inside the triode, then its an eye opener.?? Peak fault current goes sky high,

then HV fuse opens? up? <? 2 msecs later.?? The back emf on the? choke is? sky high.???? Even if a glitch resistor? +? HV fuse were not used,? and B+ arced,? and mains? breaker /? fuse opened up,

this may still explain choke failures? on henry radio amps.

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A? C-R-C network will reduce? the? ripple in half, vs just a? C? filter by itself.? C filter in the 2nd case would be just the?? C1? +? C2 caps? in parallel.

A? C-L-C? filter? will reduce the ripple down to nothing... like? -113 db.?? Ripple on my drake? supply is? -30 db.

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Duncan? Monro,? M0KGK? responded? a few? hrs ago, that he is working on? PSUD-3.?? IF any of you that use? PSUD-2? note any screwball? results, he needs your files asap.

The idea is the? offending parameters, anomalies,? can be tested on the new PSUD-3 version,? before releasing it.

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There are a? few other items that need to be addressed, like?? outputting ripple results in? peak to peak,? and also in RMS, and also in – XXX? DB.?? For commercial use,

expressing ripple in –db is typ.? Although the stepped load feature of? PSUD is useful, it does not simulate a real world varying load, like you would have on SSB, AM,

or an audio amplifier application.?? IE:? a real world? dynamic load.?? The stepped? load feature on PSUD-2? either removes the load asap, or slams a load on asap.

Thats? good enough for cw use..and thats it.?? The current version of? PSUD-2? will depict?? RMS ripple current into the C1? and also C2 caps.?? It’s the only tool I have found that

will at least depict? ripple current into a simple C filter... which is? typ?? 2 to 2.5? times the loaded DC current.? Which also explains why some caps will internally heat up

using high duty cycle modes like data, AM,?? FM etc,?? and or? dry out quicker.?? Typ larger value caps also have higher? ripple current ratings.

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Filter ringing, overshoot,? and number of cycles? before the? ringing subsides..and also? LP filter cutoff? need to be addressed.?? As is,? PSUD-2? will only handle? single phase power supplies, and only? a choice of

50-60-400 hz.???? 3 phase? would be an excellent addition... but there are also? typ 3 ways to design the? 3 phase supply.?

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What else that needs to be addressed is? ripple at the harmonic freqs,? like??? 240 hz, and also? 360,? 480, 600 hz, etc.?? IF in the UK,? Japan etc, then its

100-200-300-400-500-600 hz.? On single phase,? ripple Freq is? just 2 F.?????? On 3 phase, ripple freq is now? 6F, so ripple is at? 360, 720 hz? etc.

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Hopefully, the anomalies? and enhancements?? will materialize.?? If anybody has other ideas for? PSUD-3,? Duncan can be reached at

duncan@...?? or?????? postmaster@...?

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The idea is to get? PSUD-3? to a pro level.?? Its used by a lot of folks (besides hams)? ?world wide, but as is, it has limitations.

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Jim? VE7RF

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