@Aleph(0) , @Jazz2C and just anyone who cares!

Below is the ('real-world verified') wiring diagram for the passive EHT indicator -- Please! Everyone/anyone! - Advise me of any ambiguities, drafting errors, omissions, etc!

At your mercy
HP

ETA -- Image edited for clarity

 

Hp please listen to this tune! It so exquisitely describes my feelings that I wish I wrote it myself! Hp I know it doesn't change anything! I'm totally at peace with that! I just want you to know how I feel! Not b/c it will change anything but I just need you to know! I don't really know why other than just that knowing that you totally understand how I feel gives me peace of mind.

Very well... I did listen and I must say it makes me rather sad inasmuch as it speaks of a great deal of 'emotional energy' which could be so much better invested!
Passing fancies are just that!

HP I almost hate to say it but I'm starting to think JC's feelings for you aren't just passing fancy but the real thing! So I say you have to handle it totally carefully cuz a broken heart is usually also like a broken mind which isn't conducive to discipline needed for academic success! Just sayin! Now @Jazz2C sry if I'm embarrassing you but you're the one who keeps making it public!

Later than that in the event of a US Govt shutdown at the end of this month

HP that totally depends on duration of shutdown Anyhow as contractor I'm not obliged to do work of furloughed federal employees and anyhow Troy and Kathleen totally agree that shutdown is breach of contract by feds so I can withdraw and retain funds which I say is tempting on principle alone! By terms of contract I can also sue for damages which would be multiple of funds already received! So withdrawal or bringing lawsuit would be breach of _professional courtesy ethic_ but I say Govt shutdown is silly game played by politicians on backs of American ppl so I say if it comes to shutdown I'll have decision to make!

@Aleph(0) , @Jazz2C and just anyone who cares!

Below is the ('real-world verified') wiring diagram for the passive EHT indicator -- Please! Everyone/anyone! - Advise me of any ambiguities, drafting errors, omissions, etc!

At your mercy
HP

ETA: The values of the shunt and calibration resistors (i.e. RCB, RCN & RCP) shown below represent calculated values under a 'perfect world paradigm' -- The full-values of the corresponding potentiometers are 5k, 1k, 1k (respectively)...

OOPs! The schematic neglects the fact that RCB is a potentiometer -- So noted!

HP ok so NOW I get it! In balanced mode floating DC HV psu goes between RD1 and RD2 then meter and chassis are grounded to prevent corona and electrostatic forces?

So in unbalanced mode HV psu has grounded end connected to chassis and _hot_ end to RD1 or RD2 depending on its polarity?

So to calibrate you set RCB first for balanced mode shunt and then calibrate for each unbalanced mode by adjusting RCN in negative ground mode and RCP in positive ground ground mode?

HP I say make sure instructions say current drain in unbalanced modes is 2X the current in symmetrical mode for given voltage! So unbalanced voltage limit should be 50kv (125uA, 6.25W) which is good plan anyhow to prevent flashover of just the single resistor tower in use!

HP I say you should give formula so ppl with different dropping resistors and meter movements can _ballpark it_ too!

So here:

For 1 to 1 correspondence of input kV to meter uA in balanced mode:
Rcb=Rm*(Rd1+Rd2)/(10^9-Rm-Rd1-Rd2)

Where:
Rcb=Shunt resistor for balanced mode
Rm=meter movement resistance
Rd1 and Rd2 = dropping resistances (which are each ≈400M in HP's circuit)

So for unbalanced modes it follows that:

Rcn=Rcb*Rd2*Rm/(-Rd2*Rm-Rcb*(-10^9+Rd2+Rm))
Rcp=Rcb*Rd1*Rm/(-Rd1*Rm-Rcb*(-10^9+Rd1+Rm))


Now just for example I can plug in values from schematic:

Rcb=750Ω*(400MΩ+400MΩ)/10^9-750Ω-400MΩ-400MΩ)≈3kΩ
So
Rcn=3kΩ*400MΩ*750Ω/(-400MΩ*750Ω-3kΩ*(-10^9+400MΩ+750Ω)) ≈ 600Ω
Rcp=3kΩ*400MΩ*750Ω/(-400MΩ*750Ω-3kΩ*(-10^9+400MΩ+750Ω)) ≈ 600Ω

So my math jibes with HP's but plz remember that in real life RD1 and RD2 won't be exactly equal so neither will Rcn and Rcp

HP all the whys and wherefores make it too easy for stupid mistakes so I say plz fix post #943 and tag ppl who have shown past interest in thread to have a look too!

So I'm thinking of like
@shortbus & @#12 & @JoeJester & @The Electrician & @KL7AJ & @Wendy & @Sinus23 @Robert Clark & @tjohnson and everyone I missed and everyone's totally welcome! Hey ppl plz let us know how it's looking and don't hold back on criticism cuz we can take it!

 

I say plz fix post #943

Done! --- Backatcha later - 'tis been a looong day!

Best regards
HP

 

@HP I just looked at your new email abt EHT meter construction and I like what I'm seeing!

So I say you're totally right to make allowances for readers who don't have 3D printers cuz that's not something everyone has. Also PTFE printing is a PITA cuz of narrow margin between MP and pyrolysis temp (HP I know non crystalline substances don't really have melting points so just chill cuz you know what I mean)

HP Just for a test I printed PVC tube to same dimensional parameters as section of schedule 40 PVC pipe from home center and even using Chemson's best vinyl filament printed version is brittle and much lower tensile strength! So I guess there is a wide range in grades of vinyl but I also say additive methods just can't compete with extrusion where form strength is concerned!

So like you know I should be back to regular schedule by middle of next month but not until early June if protracted US Govt shutdown causes scheduling conflicts BTW plz make sure to vote on my poll in off topic!

HP I know you've been working very hard on EHT meter tutorial so thx for recognizing fact that we need _psychological advantage_ of actually completing something for morale going forward!

 

So I say you're totally right to make allowances for readers who don't have 3D printers cuz that's not something everyone has.

Indeed! Lest I chase prospective enthusiasts away via requirement of 'specialized equipment' (granting that '3D printers', etc are now mainstream in 'The West' such conveniences remain akin to 'exotic novelties' in many areas). Moreover, I have extensively tested commonly available 'plumbing grade' PVC and CPCV forms/products for desirable electrical, structural, chemical and thermal characteristics. Insofar as as much of the pertinent data are not readily available from polymer manufacturers, the requirement of testing and 'certification' of specific filament compositions as 'project compatible' would be all of burdensome and, I daresay, dubious -- especially as certain characteristics (e.g. chemical stability in the presence of elevated O3/NO2 concentrations) are not readily ascertained over the short term...

Also PTFE printing is a PITA cuz of narrow margin between MP and pyrolysis temp

Although 'doable', I regard the published disparity in electrical (spec dielectric) characteristics as cause for dubiety as regards 'printable PTFE'...

...but I also say additive methods just can't compete with extrusion where form strength is concerned!

FWIW Such has long been my observation with a wide range of materials (à la the structural superiority of 'cold rolled' iron products)...

HP I know you've been working very hard on EHT meter tutorial so thx for recognizing fact that we need _psychological advantage_ of actually completing something for morale going forward!

---Emphasis added---

Agreed! Moreover said instrument is all of required from the 'get go' (Re: the EHT projects), not readily (commercially) available (Re: balanced operation) and offers the not-insignificant safety advantages attendant to 'hands free' operation (a vital consideration in view of the 'Nube Factor')

Very best regards
HP

 

HP looking on new images in blog it looks like you're just abt done with meter? So b4 you take off on Thursday plz post image of completed project on here so we're on same page for wrap-up when I return!

 

HP looking on new images in blog it looks like you're just abt done with meter? So b4 you take off on Thursday plz post image of completed project on here

Indeed! All that remains is fabrication of the test leads/connectors...

I've several images yet to upload in addition to those of pending work -- So... If you're interested, please keep an eye on my blog --- Important! Inasmuch as new images are added via 'edit' you will not receive alerts to same!

FWIW I plan to post the descriptive images to this thread!

Very best regards
HP

 

@Aleph(0)

FYI - Construction/testing of the passive EHT indicator is complete - I've merely to 'up' the remainder of the photography and compose a cursory step-by-step - All of which must await next week (lest I get off to a late start - as usual)

So... In the words of that 'crazy', retro Englishman (Who's name I can't be bothered to Google at the moment):

"My time has come to be gone..."

See you next week!
HP

ETA -- Please see my email message in regards to the 'merits' of a Faraday mesh...

 

All of which must await next weak (lest I get off to a late start - as usual)

HP I say w/w error smacks more of early start than late start!

So anyhow looking on pic of completed meter in email I say it looks like it could be at home in Frankenstein's lab!

So I'm saying good work and plz have a safe trip!

 

good work and plz have a safe trip!

Thanks! Be advised that I've returned safe and sound! --- That said, I must confess to being a tad 'bummed' at the bleak prospect of nothing to look forward to for a while now the Hamvention has come and gone

So anyhow looking on pic of completed meter in email I say it looks like it could be at home in Frankenstein's lab!

Is that good or bad?

HP I say w/w error smacks more of early start than late start!

Indeed? As with all things EtOH(?) I must defer to your superior experience/knowledge on the subject --- W/W error corrected!

Best regards
HP

 

Is that good or bad?

HP that's hard to say cuz for some ppl it gives it _awesome factor_ but to others it could be more like _Toys R Us factor_

 

HP that's hard to say cuz for some ppl it gives it _awesome factor_ but to others it could be more like _Toys R Us factor_

Probably closer to the latter in the eyes of most -- But hey! It works well and that, as 'they' say, is what it's all about! --- FWIW I expect to post the annotated images within the next few days (which being at my nearest opportunity/convenience)...

Best regards
HP

 

Wow! Just wow!

Why don't you two get a room?

 

Why don't you two get a room?

Well ya see... Apart from the facts that @Aleph(0) and I are straight and of like gender - I'm her 'dear old' mum!

I can but hope this finally clears the air on that point!

Tolerantly
HP

PS Chat with y'all in a week (give or take)

 

Well ya see... Apart from the facts that @Aleph(0) and I are straight and of like gender - I'm her 'dear old' mum!

I can but hope this finally clears the air on that point!

HP I say since you've posted that we're blood relatives like a zillion times b4 they should already know it! Anyhow @KL7AJ since you have to go back like 9 months just to take something out of context I say we must be doing better at staying on topic

 

@Hypatia's Protege:
Thank you for clearing up the mystery. It appears that the apple really doesn't fall far from the tree!

 

@Hypatia's Protege:
Thank you for clearing up the mystery. It appears that the apple really doesn't fall far from the tree!

You might think differently were you privy to our interminable squabbles

Best regards
HP

 

@Aleph(0)
Should you yet wish me to photograph and upload images of the Siemens Polyphos generator components please let me know ASAP! -- As you well know next week is right out!

Very best regards
HP

 

Should you yet wish me to photograph and upload images of the Siemens Polyphos generator components please let me know ASAP!

HP Tnx! That way I can post images with my question on general E. Chat forum!

As you well know next week is right out!

HP I wish it was totally out! But at least it will be a good job well done!

@shortbus
Plz let me know that you received my response to your PM

 

Yep. Did you get mine?

Soon people will think we're conspiring.