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Re: Plate Blocking Capacitors again
开云体育Not always: ?
? 73 Peter ? From:
[email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF Current? rating? on? mica's? decreases as?
freq? increases.? |
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Re: Plate Blocking Capacitors again
I'd be? more? worried? about? the? current? rating..vs? V? rating.? ?What? bands are? you? planning? to? use..and? what? tube(s) ?? ?If? u? are? using? tubes? with? typ stray? C? between? anode? and? grid (assuming a GG? triode...or? ?tetrode..strapped? like a? high? ?mu? triode)....? the? current? through the? plate blocker? can? get? pretty? high? on? the? upper? bands? like? 10m.....? it's? easy? to? calculate? plate? block? current.? ?Alpha? just? uses? a pair? of? 6? kv? disc? ceramics? in? parallel? for the? plate blocker.?
Problem? with? mica's? is.... they? rate? em? for? current at? 1? mhz? (and? in? ur? case,? 300? khz) .? U? might? be? able? to? test? by? feeding? RF? through? the? mica...then? into? a dummy? load.? ?200w? is? 2A? into? ? 50? ohms.? Then? try? all? bands.? Current? rating? on? mica's? decreases as? freq? increases.? Jim? ?VE7RF? |
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Re: Plate Blocking Capacitors again
开云体育?
Many thanks for that Peter.
At 10kV peak working that capacitor looks to have a much lower rating than mine.
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73s Tracey G5VU
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Re: Plate Blocking Capacitors again
开云体育Seems to work ?
? 73 Peter ? From:
[email protected] [mailto:[email protected]] On Behalf Of Sharalyn Koeppe ? I have understood that mica is not suitable for plate blocking due to dielectric migration from the DC applied. 73,?? Roy??? K6XK ? On 1/19/2020 7:36 AM, Tracey Gardner via Groups.Io wrote:
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Re: Plate Blocking Capacitors again
开云体育I have understood that mica is not suitable for plate blocking due to dielectric migration from the DC applied. 73,?? Roy??? K6XK
On 1/19/2020 7:36 AM, Tracey Gardner
via Groups.Io wrote:
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Plate Blocking Capacitors again
开云体育?
I have an 1100pf large block shaped Dubilier?mica capacitor?dating from 1944.
It measures approx. 3.75w x 2.25d x 3.25h inches
It states on it that it was tested as follows
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(a) 6 amps at 300kHz for 1 hour
(b) 28kV dc
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It also states that the max working conditions should be approx. 80% of those ratings.
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Considering its age has anybody got any thoughts on if it would be safe to use?
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It still measures?1106pf
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Thanks
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Tracey G5VU |
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Re: Interesting High Voltage capacitors
OK, I? downloaded? the? entire? catalog on? that? series.? ?Most? are? rated? at? c 100 Amps? of? ripple? current....? but? at? lower? ambient? temps.? ?Per? cornell? dublier? ( who? bought? out? ?Mallory)....? for? applications? like? dc? drives etc,? where? high? currents? are involved,? caps? are? wired? in? parallel? to? increase? the? current? rating.? ?Per? CD,? the? 10-32? screw? terminals? are? rated for? 30A? CCS.? ?The? 1/4-28? terminals? are rated?for? 50A.? ?Caps? can? also? be? wired? series? parallel for? both? more B+? and more ripple current.
Using? PSUD-2? software.....? (and? also Hammond? xfmr? notes), the? ripple? current is? typ? 2.5 X? the DC? plate? current.? ? Similar? results? using? ?Spice? and? LT spice? software.? ?So? if? u? are? sucking? 1A? of? plate? current, ideally,? u? want at? least? 2.5A? ripple? current? rating.? Ripple? current? ratings will? increase? when? ambient? temp surrounding the outside? of? caps? is? less? than? the? typ 85? deg C? rating? (or? 105? deg? C).? ? CD? has? ripple current? multiplier? charts? on?their? site....? for reduced? ambient? temps....and? also? when ripple? current? freq? is? > 120? hz.? I? suspect? those? ?135mm? diam? x? 300mm? long? caps? ?will? be in? the? $200.00? to? $300.00? ?price? range.? Jim? VE7RF? |
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Re: Interesting High Voltage capacitors
开云体育?Friday, January 17, 2020 ?In an RF amp where might be appropriate to use Teflon capacitors? Best regards, ?Chris ? ?2E0ILY ? ? ??mailto:chris@...
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Re: Interesting High Voltage capacitors
开云体育Those are DC link Capacitors. I have used them for years now in
amplifiers. Not that brand though.? I used the 944U. They make
them up to 1.4KV at 70UF.? Or 1.2KV at 100 UF.? That is full
working voltage and you are allowed 50% more at less current. They
are rated in AMPs. So in HV B plus service you would never pull
any serious current. They look like a hockey puck and are easy to
mount. I will look into this new brand.? C On 1/16/2020 6:50 AM, Jim VE7RF wrote:
I? downloaded? their? entire? catalog? in? that? series.....4? days? ago.? ?Now? I'm? having a helluva? time bringing? it? up. -- Please let me quote you for your parts needs! I offer a discount on Protunes with parts order! Clark Turner 480-695-2898 |
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Re: Silly as it gets
开云体育G’Day Jim, ? You made a very good post to round-off this entertaining thread of posts largely by Ned Flanders type insufferable puritans. ? My other two takeaway quips from the most amusing read were those of: ? RAF flying ace Douglas Bader who once said "Rules are for the guidance of wise men, and the blind obedience of fools" ! ” ? and ? “Just get on the air and have some fun, don't worry about what everybody else is running!!! ” ? With just one overriding proviso: As long as your QRO signal is clean in respect of spectral emissions and not interfering with others sharing the band…..easily attained if the operator is technically competent. ? 73 ? Leigh VK5KLT ? From:
[email protected] [mailto:[email protected]] On Behalf Of Jim VE7RF ?
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Re: Interesting High Voltage capacitors
I? downloaded? their? entire? catalog? in? that? series.....4? days? ago.? ?Now? I'm? having a helluva? time bringing? it? up.
Can't? remember? if? they? stated? ESR at? ?100/120? hz? (and? also? 10? khz) ?? ?Some? of? their? biggest? caps? were? huge? monsters...? like? 150mm? /? 6"? diam !? ? Are? these? caps? electrolytic's? on? steroids ??? ? ?Are? they? constructed internally? like? conventional? lytics ?? ?Did? not? see a price? tag.? ? On? paper,? they? should? do? the? trick.? ?Is? the? ?Neg? terminal bonded? to the? outer? aluminium? casing? like a regular? lytic ?? ? The? 900/1100 etc? vdc? types,? strung? in? series,? will? still? have? to? be? isolated from? each? other..and? chassis,? like? conventional lytics...+ a 100K? resistor across? each? cap.? I? THINK? they? had? em? rated? as? high? as? 3? kv?? I? believe? you? are? onto? something? here !? ? ?My? 10,000uf? @? 450? vdc? lytics? work? fine,? but? I? need? a lot? of? em? in? series? for? my? 5700/7700? vdc? supply.? My? ?10,000 uf caps? are? .0159? ohms? ESR? @? 120? hz...(each).? ? ? You? should? contact? the? manufacturer? for? more? detailed? info.? ?Then if? possible,? buy a? bunch? of? em.? ? Then? let us? know? the? results.? Jim? ?VE7RF? |
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Interesting High Voltage capacitors
I came across these capacitors while searching for HV electrolytics.
They are available upto? 2kv, are dry sealed, and available upto 1000uf or more. They are also rated for high current DC operation It might be a quick? and compact way of creating a 10kv high voltage dc capacitor. EPCOS TDK Brand. Anyone used them? |
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Re: Coil 3.72 software
He? took? SS? off? the? list.? It's? beyond? piss? poor......sky? high? RF? resistance.
N6BT,? original owner of? F12? tried? using? 8? gauge? solid? SS? wire? for? the helical? hairpin? coil? on? a? 40m? yagi. Like? 5? turns? on a 3"? diam? coil, large? spacing,? air? wound. Dead? center? in? the? coil,? it? turned? BLACK,? with just 1.5? kw? SSB !? ? The? exact center of? a helical? hairpin? coil? is? an electrical? neutral? point.? (extreme? high? current,? zero? voltage) Te? exact? center? can? either? float..(hairpin)? or? bonded? to a boom,? (beta? match).? The? point is,? SS? is? the? worse? conductor? for? RF,? bar? none.? ?Forget? making? a? coil? out? of? it,? plus? u don't? want? to? use? SS? screws? and? bolts? the? way? F12? did? at the? feedpoint? of a yagi. where? they? double? nutted? the? 10-24? SS? machine? screw,? with balun? wires? terminating? on a crimped? ring? connector....? ring? connector? sandwiched? between? the? SS? flatwashers? and? SS? nuts? on? either? side? of the? ?ss? flat? washers.? ? In? that? case? all? the? RF? flows? through? the? SS? machine? screw.? ?IF? the? ring? terminal? is mashed? against? the? AL? tubing.. and? a machine? screw +? SS flat washer +? SS? nut? used? to mash? the? ring? terminal? against the? al? tubing,? its? then? ok.? I? had? to? replace? the SS? machine? screw? on? my? vac? tune? cap,? where? I? had? stupidly? put that? small? tubing? coil? between plate block? cap? and? C1? vac? tune? cap.? Replaced? with? silver plated? brass? hardware. Problem? solved.? ? SS? is? fine,? as? long? as? it? doesn't? have? RF? flowing? through? it.? ?Brass,? bronze, and? phosphor? bronze? is? preferred,? and? also? easy? to? silver? plate? all? 3.? Jim? ?VE7RF |
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Re: Coil 3.72 software
开云体育Wow!. I got the hang of it. Good fun and very useful for my current project. 73, Alek. On 9/01/2020 7:09 am, Alek Petkovic
wrote:
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Re: Coil 3.72 software
开云体育Ah. I think I have it! I was waiting for the fields to clear when I clicked on the
arrow/s. For some reason, they don't but it is ok, because you
just have to type over the existing numbers. Found it by accident. Never would have guessed in a million years otherwise. Thanks and 73, Alek. On 9/01/2020 12:16 am, Jim VE7RF wrote:
Did? u? ?read? the? notes ?? ? ? Use? the? up and? down? arrows? to? ?change the? parameters? in? the? center? ?section.? ?Or? use? the? mouse.? Use? mouse? for the? 2 x end? blocks.? I? have? 2 x? coil 3.78s? up? right? now.?? |
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Re: Coil 3.72 software
Sand,? salt,? rock salt? have? been? used? by a buddy.? ? ?Then? ?u? have? to? get? it? all? out !? ? ?Buddy? tried? suction? at? one? end.....and? compressed? air? at? the? opposite end.? ? Sorta works.
Table? salt? is? easier? to? get out....? toss? the? completed? coil? into? SS? kitchen? sink? full? with? hot? water.? ? Salt? just? dissolves.? I? have? NOT? needed? to? use? salt? on 1/2"? tubing...? with? an ID? of? 2.5? to? 3.0? inches.....? ditto? with? 1/4"? tubing with a 1.5"? ID.? I? did note? that when? 3/8"? tubing? is? wound on a 1.5"? ID, (NO? salt)? that? the? tubing? ends up? flat.... on? top? +? bottom....and? curved on? both? sides.? ? I? like? the? results.? ?That? coil? was 6.5? turns,? aprx? .66 uh,? installed? between? plate? block? assy..and? C1? tune? cap? on? my? hb? 3CX-3000A7.? ?Coil? was? silver? plated..after? the? fact. I? wind? all? the tubing? coils,? with? turns? TIGHT? together.....? wound on? an? appropriate form,? al /steel tubing.? or PVC,? spray? can,? doweling? etc...with? plenty? of? slack / excess/ lead? length? ? Coil? is then? slid? ?off? the? form.? Biggest? flat? bladed? screwdriver I? own,? is? then? used? at? beginning? of? coil,? and? rotated,? to? induce the? correct? space between? turns? 1+2.? ?Blade? moved? along,? then repeat? the? process? over? and? over,? spiraling? around? ?and? around? the? coil,? till? u? get to? the? other? end.? Then? some? minor? tweaks here? and? there.....? then? done.? ?Coil installed...? leads? formed? a bit ( tubing? spring? ?slid? over leads,? so? tubing does? not? flatten.? ? Any? excess? cut off in bandsaw.? ?Ends? flattened..and? then? punched? with? correct? hole? size.? ?Coil? and? leads? are then? silver? plated.? The? entire? mess free stands.?? Check? out? the? YC-156? ?80-10m? amp? pix? I posted on? the? photo? pages.? ?There? u? can? clearly? see the? tubing? coils? and also? strap? coils.? And? also? the tapped? tubing? coil? used for the? tuned? input.? ?All those? coils? +? straps are hb,? and? all? silver plated with? cool-amp? glop.? Entire? process is? cheap....just takes? some? time.? ?End? result? is? professional? looking.? ?IMO,? these? hb? amps? are just? one? big? metal? work? project.?? Jim? VE7RF |
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Re: Coil 3.72 software
开云体育Make sure you read the text files.? You will need to create a shortcut and change some of the parameters before it works correctly. ? Jim – KR9U ? From: [email protected] [mailto:[email protected]] On Behalf Of Alek Petkovic
Sent: Tuesday, January 7, 2020 11:34 PM To: [email protected] Subject: Re: [ham-amplifiers] Coil 3.72 software ? I got 3.79. Question. How do you change any of the values/parameters? When I open the program, it shows a pre calculated example and there seems to be nothing I can do to change frequency, wire size, inductance, etc, etc. Everything just stays the same. The whole thing is a waste of time, in my view. 73, |
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Re: Coil 3.72 software
开云体育I got 3.79. Question. How do you change any of the values/parameters? When I open the program, it shows a pre calculated example and there seems to be nothing I can do to change frequency, wire size, inductance, etc, etc. Everything just stays the same. The whole thing is a waste of time, in my view. 73, Alek. VK6APK On 8/01/2020 1:52 am, Jim VE7RF wrote:
Latest? version? is? now? 3.78 |
Leigh Turner
