@Jazz2C --- I crave a single, vital boon -- Inasmuch as we are - and are now known to be - 'real world' acquaintances - please do not 'like' ('up-vote') my posts! -- Lest you be taken as a 'straw-man', 'puppet' or 'kowtower'

Hp! I'm sry! I totally forgot! So I just unliked the two likes I gave you! I hope that's all I have to do? @Aleph(0) plz help me with this!

 

Yo HP! Sry I missed a chance wish you bon voyage

HP b/c you do media clips here I chose this as a farewell tune for you on expedition! You should know I chose carefully so it reflects my true feeling!

Good move bright boy! HP will do her pieces when she sees that! Cuz it's you being too familiar again and giving description info too! Looks like I can watch more fireworks at end of month!

If I were you I'd talk to IT before continuing with that VPN when security counts!

I say better solution is that I contract another it team! It's been every type of dreck from the word go with them!

Hp! I'm sry! I totally forgot! So I just unliked the two likes I gave you! I hope that's all I have to do? @Aleph(0) plz help me with this!

So you made a mistake then you corrected it then you came clean about it in true George Washington style. I say you don't need any lessons in self ingratiation from me!

Tnx HP! Now I just need to know what the little screw in the oil filler plug is for? Mine has one too but it's seized and I'm afraid to use too much torque to loosen it b/c if it shears I'm sol again!

JC That's vent to prevent pressure buildup when oil gets hot. So if you can't loosen screw just loosen plug enough for gas flow when you use dvdr but remember to close it again b4 oil cools off or it will absorb moisture

 

Green Eyed Lady mmmmmm..
Played it for some kids last week. Goggle eyes.
Used to play it a cover band. Like the guitar licks... Some serious octaves.

Yeah, off topic. I will chastise myself...

 

Yeah, off topic. I will chastise myself...

Johnintx You sure don't have to sweat off topic comments on this thread! We hope that will improve when HP is back so we're on with more cerebral topics like fb drivers

Green Eyed Lady mmmmmm..
Played it for some kids last week. Goggle eyes.
Used to play it a cover band. Like the guitar licks... Some serious octaves.

Johnintx I say that song's so old it's pocked by debris from KT impactor

 

HP will do her pieces when she sees that!

Sounds interesting!

Cuz it's you being too familiar again

It's me being honest! That's all

and giving description info too!

Hey now! Hp is using an avatar that anyone who's ever met her would say is a pic of her without hesitation! So revealing her actual eye color isn't a big deal! I think it's funny how you both carry on abt privacy but then use avatars that identify you I understand abt your idea to be recognizable to personal acquaintances but untraceable through avatars but it seems counterproductive to me

So you made a mistake then you corrected it then you came clean about it in true George Washington style. I say you don't need any lessons in self ingratiation from me!

Yeah! Ok! Whatever!

JC That's vent to prevent pressure buildup when oil gets hot. So if you can't loosen screw just loosen plug enough for gas flow when you use dvdr but remember to close it again b4 oil cools off or it will absorb moisture

Huge thanks! Where should the cold oil level be?

I say that song's so old it's pocked by debris from KT impactor

You know what the natural historians say? "It's not the dino's you kill but the Chicx_U_lub(e)". It was all happening in prehistory!

 

Sounds interesting!

JC since you insist on building your own coffin, I say mahogany is nicer than pine

It's me being honest! That's all

IMO it's you being obnoxious, but we'll see what HP has to say!

Hey now! Hp is using an avatar that anyone who's ever met her would say is a pic of her without hesitation!

I think it's funny how you both carry on abt privacy but then use avatars that identify you I understand abt your idea to be recognizable to personal acquaintances but untraceable through avatars

I say "it's funny" how you get it without getting it and NO double entendre intended!

"It's not the dino's you kill but the Chicx_U_lub(e)".

Hey JC relax! With a show of a little initive I'm sure the principal will let you into 7'th grade this year

Huge thanks! Where should the cold oil level be?

Between 5mm and 1mm of the lowest plug threads. Too low is to risk arcing and damage, too high and it spills oil when hot so too much is way better than not enough!

 

You'ze guys is silly. But it is so entertaining to listen in.

 

You'ze guys is silly. But it is so entertaining to listen in.

Enjoy it while it lasts! I guess we're going to get all studious and scientific-like when HP is back!

 

Yo Aleph! I searched the whole site. Hp only mentions solarization twice in passing on two different threads but not on EHT design thread So it must have been among the, as she termed it, "extraneous" material she deleted from the tutorial post?

I can't find it either So like you say she either deleted it from tutorial or posted on another chat site and I had blonde moment about where

 

I can't find it either So like you say she either deleted it from tutorial or posted on another chat site and I had blonde moment about where

I really really really need someone like you in my R.F. lab! What would it take to get you up to the sub-Arctic? I have a warm guest igloo.

 

I can't find it either So like you say she either deleted it from tutorial or posted on another chat site and I had blonde moment about where

I really really really need someone like you in my R.F. lab! What would it take to get you up to the sub-Arctic? I have a warm guest igloo.

So my disorganization is a qualification? Now I'm saying you have bad case of igloo fever

 

JC since you insist on building your own coffin, I say mahogany is nicer than pine

Yo Aleph! You set that one up

IMO it's you being obnoxious, but we'll see what HP has to say!

I can take it!

I say "it's funny" how you get it without getting it and NO double entendre intended!

Yes! Aleph! I get it that HP and you want to be recognizable to acquaintances but not strangers. But looking at your respective avatars is totally like looking at photographs of you both. So what's the point of not just using photos of yourselves in the first place?

Hey JC relax! With a show of a little initive I'm sure the principal will let you into 7'th grade this year

The first time I heard the "Chicx_U_lub(e)" joke it was told by that hippy paleontologist from PBS! But I don't know his name and google is ignorant on the subject OBTW with a little "initive" you could learn to spell

Between 5mm and 1mm of the lowest plug threads. Too low is to risk arcing and damage, too high and it spills oil when hot so too much is way better than not enough!

Tnx! It looks good so I took it to 100kv with 10 megohm DMM as the volt meter and no problems

So my disorganization is a qualification?

In which case you should be directly commissioned to principal investigator!

I really really really need someone like you in my R.F. lab! What would it take to get you up to the sub-Arctic? I have a warm guest igloo.

Be careful what you wish for! In all fairness Aleph is phenomenally easy on the eye but her allure ends there!

 

Yo Aleph!

What do you suppose HP has planed for this point in the EHT course?

....WORK IN PROGRESS.....

=======================

It's Step Preq_4 right after task 7
I think it would be thoughtful to do some work on the course prior to her return

 

I think it would be thoughtful to do some work on the course prior to her return

JC leave it be! It's HP's baby! Proofreading is ok but messing around with content is verboten!

 

Be careful what you wish for! In all fairness Aleph is phenomenally easy on the eye but her allure ends there!

even though ethanol can be said to be antidotal for methanol poisoning (b/c of ADH's greater affinity for and resulting prioritization of metabolism of the former) it is a bad mistake to think an abundance of ethanol in a solution containing methanol makes it safe to consume!

JC Here's parallel of the quotes: Mixing complement with insult is still insult just like mixing antidote with poison is still poison so you lose!

 

JC leave it be! It's HP's baby! Proofreading is ok but messing around with content is verboten!

Thanks, Aleph -- Please know that said 'policy' owes not to a 'thirst for autonomy' but, rather, a desire for 'continuity of voice'...

I guess we're going to get all studious and scientific-like when HP is back!

That's the plan!

You should know I chose carefully so it reflects my true feeling!

JC, while I'm genuinely honored by your sentiment - I am, nonetheless, bound to opine that your fancies in this regard constitute a distraction you can little afford! Please endeavor to focus your 'energies' upon your studies - Lackluster 'tho such may now seem, a lifetime's quality time hangs in the balance

So the WX has granted me a 'home visit' - just enough time to rest up and head back -- Play nice the both of you! -- I'll be another week (at least) thanks for your continued patience!

Best regards
HP

 

@Aleph(0) , @Jazz2C et al

This will be my final visit to this site prior to completion of the dive -- No need to worry about the tutorial - we'll sort that out upon my return

Very best regards
HP

 

@Aleph(0) & @Jazz2C
Once again conditions (i.e. 'heavy seas') have resulted in postponement of the raising attempt
So... I'm home today and most of tomorrow then back at it next week --- All ballasts are in-place and ready for deployment - hence, given a few hours' 'reliably calm' conditions, the operation should be completed whiten the next few days -- whether it will have been worth the not-inconsiderable effort remains to be seen
In the meantime, such that we might 'hit the ground running' upon my return, I request that you please resume proofing the tutorial! -- BTW @Jazz2C while I neither expect nor desire that work on the tutorial 'competes' with your studies - Might I ask that you 'go AWOL' from Call of Duty long enough to put forward some effort in this regard?

Very best regards
HP

 

--- Place holder ---

 

LOPT preparation tutorial development
Last action @ 08:37 UTC Jun 26 2016 -- Moved to end of thread @ 7/24/2016

Scope of series:

Central topics:
This tutorial is one in a (prospective) series with focus upon low ripple, relatively high current/power PSU solutions for radiography and other modest photon energy (≤ 2 MeV) particle accelerator applications - and, to a lesser extent, exploration of certain 'current intensive' electrostatic phenomena (e.g. electret photography, electret formation, electrokinesis, establishment of electrostatically 'cordoned' (atmospheric) pressure gradients, high volume ion-flow systems, etc...

Peripheral and extraneous topics:
While everyone is welcome to view and post questions (within the confines of this site's TOS/UA) - Please be advised that those having interests confined to the following topics/applications will not likely find this series particularly useful (owing to the availability of significantly less 'labor-intensive' solutions to same):

--'Pedestrian' and 'Quasi'/'Peri'-EHT applications:
(e.g. CRTs, PMTs/Image tubes, Gas discharge devices, LASERs, 'negative ion air purifiers', TC primary drivers, GM tubes, etc...)
--Low current demonstration topics (e.g. 'Lifters', 'Jacob's Ladders', 'Plasma Spheres', 'Kirlian photography', 'Ion Motors', etc...)
--Capacitor discharge demonstration: (e.g. 'Quarter Shrinkers'/'Can Crushers', 'Rail/Coil Guns', 'EMP generators', electrical weapons, etc...)

Please be advised that site policy prohibits my response to most inquiries coming under the latter category...
=================================================

Scope of this tutorial
Provision of a minute, 'step by step' procedure for modification of 'heavy duty'
AC LOPTs for serious EHT application/research...

Said procedure having the following principal goals:
-- Improvement of insulation integrity via removal of auxiliary windings coaxial to the EHT winding.
-- Enhancement of versatility via electrical 'floating' of the EHT winding.
-- Appropriate adjustment of reluctance gaps.


The desirability of LOPTs:
Of the commonly available magnetic components applicable to low through medium power EHT production, the LOPT offers the advantages of relatively high power intermittent operation (several hundred Watts per transformer) and useful continuous power operation (to Ca. 150 Watts each transformer under forced air cooling). Moreover, LOPTs' amenability to resonant (and, hence, sinusoidal) drive permits development of systems productive of highly desirable mean output EMFs (≈70% peak) as opposed to the rather low (1% to 5% 'spike' EMF) characteristic of flyback and similar pulse driven/energy storage topologies. Additionally, the inherent output symmetry attending resonant drive topologies facilitates implementation of effective external EMF 'multiplication' schemes.

Prominent among the LOPT's disadvantages are the common expedient of integral rectification/EMF multiplication circuitry and 'end point' grounding schemes --- While the former objection is readily addressed via judicious transformer selection, the latter requires minor 'reconstruction', said procedure being the topic of this tutorial.

A few words regarding the unsuitability of DSTs and their ilk:
Principally
1) Integral components electrically unsuited to general application.
2) Practical impossibility of modification for improved EHT winding to core insulation.

Re: point 1 (above) Although asymmetric drive may permit peak forward (and hence output) EMFs well in excess of the internal rectifiers' PIVs - such is, of course, inapplicable to 'filtered' or otherwise capacitively loaded schemes sans additional external rectifiers - moreover internal rectification greatly complicates cascading of multiple LOPTs for increased EMF and/or development of balanced output schemes...

Re: Point 2 (above)
'DC' LOPTs are constructed as indivisible units sans 'margin' for modification -- moreover (in the case of DSTs) the rectifiers are 'distributed' throughout the winding...

LOPT Selection:
The most desirable transformers are those intended for direct production of (pre-rectified) accelerating potential for large CRTs -- Contrary to common belief such units are yet readily available from long-established electronics supply houses (whom, in my experience, are only too happy to wave 'minimum purchase' and 'wholesale only' policies at the prospect of disposal of what they regard as 'dead stock') --- That said, one should expect to size their purchase so as to offset the supplier's 'invoicing costs'... Prices as low as $20 (USD) per transformer (in reasonable quantities) are not uncommon...

The following images are offered as an aid to recognition of the desired form factor:

Assorted LOPTs typical of the desired geometry:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/lopts-jpg.101773/

Detail - Axial view:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/lopt2-jpg.101772/

Detail - Transverse view:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/nos_tyre_lopt-jpg.101774/


The modification procedure:
--Please do not commence disassembly of the transformer prior to reading and comprehension of the entire tutorial...

To Begin:
Disassembly of the LOPT unit

=======================

Step Prq_1) Identify construction style of LOPT to be optimized.

Task:
1) Identify construction style via the description most closely matching the reader's device in the following...

Full EMF AC LOPTs feature one of two general construction styles as outlined below:

Style 1) Features a single piece frame ('clamp') -- the rails of which maintain compression on the core via a single linear ligature fashioned of a metallic strap or bolt extending from frame rail to frame rail across the top of the upper form leg 'facet'.

Example of style 1
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/lopt_desc-jpg.101778/

Style 2) Features two independent metallic frame pieces OR a metallic half-frame and a backing plate/PCB -- such assemblies are bound by a single "U- bolt"/"U-strap" or two linear bolts/straps extending along the outer aspects of each horizontal form leg...

Examples of style 2

View of LOPT from 'closed' side of "U bolt" ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/ubolt1a-jpg.101781/

View of LOPT from 'open' side of "U bolt" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/ubolt1c-jpg.101784/

View of LOPT from 'closed' side of "U strap" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/ubolt2a-jpg.101785/

View of LOPT from 'open' side of "U strap" Ligature
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/ubolt2b-jpg.101786/

Step Preq_2) Removal of form frame ('clamp')

Tasks:
1) Remove any tape, looped conductors, ground leads, etc. ensnaring/bonding the frame to the form/core.

2) Free each end of the frame ligature{s}

3A) In the case of cylindrical bolt{s} or a cylindrical shaft 'U Bolt':
Remove backing fasteners (i.e. nut{s}/burs{s},etc...) then carefully withdraw the bolt{s} from the assembly.

3B) In the case of independent strap{s}, or a 'U Strap': Straighten and/or unsolder each fastening 'tab' then splay the frame rails such that the ligature 'ears' clear the ligature 'tabs' --Or-- if so constructed, remove the backing plate/PCB from the ligature ends ('tabs').

4) Remove the transformer (i.e. core and winding assembly) from the framing/clamping/mounting components -- please retain the frame and all associated hardware!

Image of transformer following removal from a single strap-ligature frame:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptdesc2-jpg.101780/


Annotation of assembly features referenced in following steps:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/annotated-jpg.101788/


Step Preq_3) Procedure for removal of strap ligature{s} from LOPT core/winding assembly:

1) Meticulously straighten and deburr the exposed segments of the frame ligature{s}.

2) Carefully 'work' the frame ligature{s} free of the adhesive, then withdraw it/them from the space intervening the form and winding assembly{s} (and, hence, off of the form) -- Under no circumstances apply counter-thrust or torque to the EHT winding!

Ligature partially withdrawn from assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptligwdr-jpg.101790/

Ligature (in foreground) fully withdrawn from assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptligout-jpg.101789/

Note: Inasmuch as same will be removed and discarded in later steps, damage to the external auxiliary windings (i.e. those on the form leg opposite the EHT winding) or coaxial auxiliary windings immediately adjacent to the core/form leg is of no consequence -- Care must be exercised, however, to avoid damage to the brittle ferrite form/core via excessive force or mechanical shock... Also - avoid handling the assembly by the EHT winding!

Step Preq_4) Removal of external auxiliary windings from 'lower leg':

Tasks:
1) Using a utility knife or similar tool, linearly section the full length of the 'external' Aux winding assembly. --- Note, the winding in reference resides on the form leg opposite that carrying the EHT winding!!!

2) Peel, crumble and/or break the 'external' Aux windings away from the lower form leg.

Step Preq_5) Separation of form pieces

Caution: In performance of the following tasks, it is of paramount importance that no torques or linear forces are applied to the EHT tyre! -- Moderate forces may be applied to the auxiliary shell and moderate compressive forces may be applied to the ferrite form longitudinal to the EHT winding 'leg' only!

3) Endeavor to remove (or loosen) any shims intervening the form and central aspect of the auxiliary sleeve -- While damage to the auxiliary sleeve or winding is of no consequence, care must, nonetheless, be exercised to avoid breakage of the form!

Image of wooden shims (indicated by pick)
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/loptshim-jpg.101791/

4) Using a #3 sharp fenestrated uterine curette, or similar non-ferromagnetic stainless steel instrument, carefully 'clean' the lower form leg of superfluous epoxy -- Note: Use of razor blades or other ferromagnetic or 'soft' metallic instruments will likely 'foul' the ferrite via metallic transfer to same!

5) Submerge the lower leg of the form (prepared as per task #4 above) in acetone for a period of ≈ 90 minutes at 16°C 33°C -- Note: the EHT winding assembly must not be submerged, splashed or otherwise wetted with acetone! -- nor should acetone be allowed to condense on same! Owing to the flammability of ketones, said procedure is best preformed in open air or in an open container under a fume hood -- a closed container is not recommended owing to liability to condensation...

6) Immediately following removal from the acetone bath, drive the reluctance spacer out of the lower form joint using an appropriate feeler gauge leaf --- Note that during and following removal of the reluctance spacer/adhesive from the 'lower' joint, application of even moderate distensive or constrictive forces to the form will result in significant cantilevered forces at the 'upper' form joint with (almost certain) breakage of one or both form pieces!

Of special concern in this regard:
A) Do not attempt to expand the gap while removing the spacer! -- The leaf thickness must be less than the gap width! Maintenance of an absolutely parallel relationship between leaf and form piece ends (i.e. gap 'walls') is imperative!

B) Following removal of the spacer, take care to avoid application of transverse pressure or piece-to-piece torsion to the form! -- The safest handling method is manipulation of the assembly from one 'side' (i.e. by one form piece) only!

7) Following clearance of the lower form joint of its reluctance spacer and adhesive, continued half-to-half form tenure owes to the upper form joint adhesive (at the center of the EHT winding assembly) - and, to lesser extent, adhesion of each form piece to the form sleeve of said assembly.



....WORK IN PROGRESS.....

=======================







=================================================


For these purposes we will consider four (coaxial) features of the EHT winding assembly:

To Wit:
(Peripheral to central).
1) The EHT 'tyre' (comprised of the EHT winding proper, potting material and bunting).
2) The Auxiliary shell (a paperboard or polymer 'collar' intervening the central aspect of the EHT winding and the peripheral aspect of the Aux winding...
3) The Aux Winding{s}.
4) The form sleeve (intervening the medial aspect of the Aux winding and the ferrite form).

Please note said features in the image below:

Image of intact EHT winding assembly.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_1-jpg.101749/


Step 1) Locate the lug carrying the EHT return:
The EHT return generally emerges with one or more AUX leads from the peripheral circumference of the AUX winding whence they are tied to a shell lug...

In this instance, said lug occupies the 2-o'clock postilion -- The image below shows said leads emerging from the Aux winding immediately below the CCW edge of the lug (as indicated by the ball-point pen) -- of special significance is the extreme peripheral position of the break-out point.

Image of the bundle containing the EHT return.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_2-jpg.101750/

Step 2) Separate and identify the EHT return:

Tasks:
1) Carefully unsolder all leads from the lug identified in Step 1 (above).
2) 'Untwist' and otherwise separate said leads.
3) Using a resistance indicator, check each lead for continuity to the EHT output contact --- the return lead will show a resistance of between 400Ω and 1000Ω All other leads should show infinite resistance (i.e. no continuity).

In the case of the demonstration transformer, three leads were tied to the lug -- the continuity examination identified the 38 AWG lead as the EHT return (said lead indicated by the pen in the attached image).

Image of separated EHT return --- Note that the associated lug was broken out of the way.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_3-jpg.101751/

Step 3) Remove the form sleeve:

Please note: Far and away the most significant challenges attending this procedure owe to the 'gossamer' nature of #38 and #40 AWG conductors... From this point onward it will behoove the reader to remain alert to the location of the EHT return whenever handling the assembly - while a severed or broken return lead is not necessarily 'fatal to the cause' - such will greatly complicate matters via the requirement of 'teaseling out' the end of a #40 or even #42 (AWG) lead from the lacquered winding!

Tasks:
1) Carefully dress the return lead out of 'harm's way'.
2) Twist, pry and/or break the form sleeve out from the center of the Aux winding.

Image of EHT winding following removal of the form sleeve. Note the EHT return at ~ "2 O'clock"
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_4-jpg.101752/

Step 4) Remove the AUX winding:

Precautions:
A) While 'unraveling' the Aux winding, apply counter-thrust only to the shell --
as opposed to the tyre!
B) While debriding residue from the 'medial gap' following removal of the Aux Shell - great care must be exercised is damage to the medial layer{s} of the EHT winding to be avoided!

Tasks:
1) Cut all leads attached to all remaining lugs.
2) Using a surgical pick or similar instrument, pry a few 'layers' of the Aux winding into the center such that they may be grasped with forceps.
Image of Aux winding prepared for removal.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_5-jpg.101753/

3) Grasp the the loosened layers and begin withdrawing ('unraveling') the Aux winding -- Taking great care to avoid application of tension to the return lead as you progress toward the periphery.

Image of Aux winding in an intermediate stage of removal.
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_6-jpg.101754/

Note: The EHT return will typically be 'laminated' between the penultimate and ultimate layers of the auxiliary winding bunting
4) Cautiously break (not tear!) the bunting material away from the return lead.

In the image below you may observe the end of the EHT return (as per the pen) and its emergence from the bunting in the gap intervening the shell and the deflected bunting medial to the remaining lug at 4 O'clock

Image of EHT return embedded in peripheral Aux winding bunting.
∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨
http://forum.allaboutcircuits.com/attachments/i1_7-jpg.101755/


Image of EHT winding following complete removal of Aux winding
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/i1_7-jpg.101755/

Step 5) Remove the AUX Shell:

Tasks:
1) Carefully break, crumble and/or fold the auxiliary shell into the 'medial gap' via symmetrical application of force to the distal labra of same at quadrature to the plane of the return.

Under no circumstances attempt to pry the shell from the interstices!!! Doing so will almost certainly damage the EHT winding beyond repair!

2) having thus loosened the shell, carefully remove the fragments being ever mindful of the return...

Images of the EHT winding following removal of the auxiliary shell...
∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨
http://forum.allaboutcircuits.com/attachments/i2_1-jpg.101757/

∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨
http://forum.allaboutcircuits.com/attachments/i2_2-jpg.101758/

∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨
http://forum.allaboutcircuits.com/attachments/i2_3-jpg.101759/



Image of EHT winding and debris following removal of Form sleeve, Aux winding, and Aux shell:
∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨∨
http://forum.allaboutcircuits.com/attachments/i2_4-jpg.101760/


Note: Should the reader's EHT winding be potted in silicone (as opposed to merely 'jacketed' as in the case of the demonstration transformer) it will be desirable to arrive at this juncture sans disruption of the potting material -- Should a breach occur, prompt repair via application of electronics grade RTV is advisable...

Step 6) Prepare The Dummy Shell:

Note: Owing to the 'brittleness' of 'Purell' grade polypropylene, use of a sharp instrument is recommended!

Tasks:
1) Excise the the base of the pharmaceutical vial.
2) Section the (resulting) cylinder longitudinal to its axis.
3) Temporarily mount the dummy shell on the ferrite form -- Verify end-clearance ≥ 5mm (form pieces in firm apposition) If end-clearance < 5 mm, trim the dummy shell to 'compliance' but try to keep end-clearence < 1 cm

Image of prepared dummy shell:
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http://forum.allaboutcircuits.com/attachments/i2_5-jpg.101761/


Image of correctly 'trimmed' dummy shell on leg of LOPT ferrite form:
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http://forum.allaboutcircuits.com/attachments/i2_6-jpg.101762/

Step 7) Prepare Return Lug:
Tasks:
1) Form a #4 solder lug such that the 'tab' is at a right angle to the plane of the fastener surface.
2) Drill a #66 (~0.83mm) hole through the lug immediately above the bend.

Image of properly prepared lug -- Notice the small (#66) hole near the fastener angle.
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http://forum.allaboutcircuits.com/attachments/i2_7-jpg.101763/

Step 8) Installation of the dummy shell:

Image of EHT winding at this juncture - note return lead:
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http://forum.allaboutcircuits.com/attachments/i2_8-jpg.101764/

Tasks:
1) Furl the dummy shell, then position it in the medial gap from the side of the winding opposite the return lead such that the 'cut' faces opposite the output 'tower'.
2) Using a stylus, etc, mark the dummy shell at the point axial to the emergence of the return and 5 mm back from the edge of the dummy shell.
3) Carefully remove the dummy shell.
4) Using a drill bit commensurate with a #4 bolt, bore through the dummy shell at the point marked in task #2.
5) Liberally coat the dummy shell and gap surfaces with electronics grade RTV. -- Avoid application of RTV to the return lead!
6) Reinstall the shell as described in task #1, taking care to position the cut opposite to the output 'tower', and the bolt hole axial to the emergence of the return lead.
7) Mount the EHT winding/Dummy Shell assembly on the ferrite form.
8) Adjust the (linear) position of the winding tyre on the shell such that the former is equidistant from the form piece angles while the end of the shell emerging from the 'return lead side' of the winding tyre extends as far as possible from the winding sans contact with the form piece.
9) Remove the form from the assembly taking care not to alter the relative position of the shell/winding.
10) Manually expand the shell as much as possible -- smooth and 'touch-up' the silicone... --- Again keep the return lead free of adhesive!
11) Allow RTV to cure for at least 72 hours at temps of 45°F through 60°F -OR- for at least 48 hours at temps > 60°F

Step 9) Installation of the Lug and connection of the return:
Tasks:
1) Carefully insert the #4 bolt from inside the shell.
2) Secure the lug to the top of the shell as shown in the images below.
3) Solder-tin the end of the return lead.
4) Insert ~ 2 mm of the return lead into the #66 hole near the base of the lug then secure it with solder.

Note: It is imperative that you neither trim nor glue the return lead at this point! - Please loop any slack as shown in the images.

Images of the assembly; Dummy shell & Lug installed, return connected:
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http://forum.allaboutcircuits.com/attachments/i2_9-jpg.101765/

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http://forum.allaboutcircuits.com/attachments/i2_10-jpg.101766/

5) Verify that the DC resistance (lug to output tower connector) -- is that measured in step #2, task#3


Anticipated FAQs
Note: the following questions approximate the 'mean' of copious feedback received at this 'stage' during composition of the original draft...

Q) The lug screw head will short the EHT return to the form -- and anyway, who wants the winding rattling around on the form like that?
A) We're not done yet! --- Patience!

Q) One centimetre is insufficient spacing of lug and winding for 50kV operation!?
A) That's why we're going to intervene lug and tyre with a thickness of PTFE in a subsequent step.

Q) Why not trim the return lead to length or at least glue it to the shell?
A) Prior to complete curing of the shell-to-tyre adhesive, and robust securing of the lug, provision for 'immunity' to relative motion of the parts makes good sense.

Q) What do spools of solder and capacitors have to do with rebuilding an LOPT?
A) The extraneous items in the images assist to achieve optimal focus -- especially as regards diminutive objects (IOW I'm using an inexpensive camera).

Step 10) Prepare the CPVC Form sleeve:
Tasks:
1) Cut a length of 3/4" (id) CPVC tubing equal to the total length of the form-leg on which it will be placed (In this case of this demonstration 8.5 cm) See the two images immediately below...

Image illustrating desired sleeve dimension
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http://forum.allaboutcircuits.com/attachments/i3_1-jpg.101767/

Image of form and adjacent CPVC section cut as per step #10
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http://forum.allaboutcircuits.com/attachments/i3_2-jpg.101768/

2) Cut shoulder stirrups in CPVC Sleeve:
Note: the stirrups must be sufficiently deep as to allow a slight amount of end-clearance when mounted upon the form (such that form-piece apposition is assured).

Image of form pieces and 'prepared' CPVC sleeve
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http://forum.allaboutcircuits.com/attachments/i3_3-jpg.101769/

Image of form and CPVC sleeve in an intermediate state of assembly
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http://forum.allaboutcircuits.com/attachments/i3_4-jpg.101770/



Image of (temporary) fully assembled form and CPVC assembly
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http://forum.allaboutcircuits.com/attachments/i3_5-jpg.101771/

Step 11) Install CPVC form sleeve in EHT winding assembly:

Image of components referenced in this step:
(L to R) CPVC sleeve, EHT winding assembly, Form [core] pieces
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http://forum.allaboutcircuits.com/attachments/1-jpg.101711/


Tasks:
1) Assemble EHT winding, CPVC sleeve and form as shown (below).
2) Using PTFE shims, center EHT winding assembly about CPVC sleeve (both sides).
Note: While the adhesive does not bond PTFE it is, nonetheless, essential that the shims be so formed as to preclude (interlocked) captivity therein!

Images of mounted and centered EHT winding as seen from 'EHT return side':
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http://forum.allaboutcircuits.com/attachments/2-jpg.101712/

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http://forum.allaboutcircuits.com/attachments/3-jpg.101714/

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http://forum.allaboutcircuits.com/attachments/5-jpg.101717/

4) Using acrylic-based 'hot-melt' adhesive, tack the CPVC sleeve to the polypropylene shell at several points each side.
5) Remove form pieces.
6) Fill the space intervening the CPVC sleeve and the PP shell with acrylic-based 'hot-melt' adhesive taking care not to disturb the relative positions of said structures!
7) Allow the adhesive at least 60 Minutes to cool/cure.
8) Withdraw the shims.

Image of assembly immediately following withdrawal of shims as seen from EHT return side.
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http://forum.allaboutcircuits.com/attachments/7-jpg.101719/

9) Fill the 'shim gaps' with acrylic-based 'hot-melt' adhesive.

Image of EHT winding assembly following completed installation of CPVC sleeve.
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http://forum.allaboutcircuits.com/attachments/8-jpg.101721/


Identification of components referenced in steps #12 through #15 (inclusive):
1) PTFE insulator.
2) EHT Winding assembly.
3) Form pieces.
4) LOPT Frame.
5) Polyolefin (heat shrink) sleeves.
6) Elastic cushions.
7) Frame ligature.
8) Form standoffs.
9) Reluctance gap spacers (see text).
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http://forum.allaboutcircuits.com/attachments/lopt_partsnum-jpg.101730/

Step 12) Prepare form guides

Prior to proceeding, it is imperative that the form pieces are absolutely free of adhesive residue, etc...!

Tasks:
1) Trim two pieces of polyolefin tubing such that they extend the full inside length of each 'winding leg' of the assembled frame (as shown below).
2) With the sleeves in place on the form, clamp or otherwise place form pieces in firm apposition with close attention to alignment of same.
3) 'Heat-shrink' the polyolefin tubing -- Note: expeditious completion of this step will significantly reduce liability to ferrite breakage (secondary to uneven application of heat) and/or permanent shift of magnetic properties (secondary to excessive temperature)...
4) Allow at least 20 Minute 'cool down' period then carefully disassemble the form such that the heat-processed polyolefin tubes remain installed on each 'half-leg of a single piece.
5) Trim another sleeve then repeat the above procedure such that one leg is bound by a double layer of polyolefin.

Image of assembled form 'sporting' the unprocessed polyolefin sleeves (Post task #1)
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http://forum.allaboutcircuits.com/attachments/preshrink-jpg.101742/

Image of form piece following processing of sleeves (Post task #4)
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http://forum.allaboutcircuits.com/attachments/separated1-jpg.101743/

Image of form piece following processing of second sleeve on (arbitrarily chosen) EHT winding 'leg' (Post task #5)
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http://forum.allaboutcircuits.com/attachments/separated2-jpg.101744/

Step 13) Fashion and place reluctance gap spacers

Note: Reluctance gaps will be incorporated to reduce liability to saturation (in all cases) and to leave the transformer compatable with 'flyback' drive topology should same be desired... --- That said, this series prefers forward transfer paradigms (as explained in the introduction to this tutorial).

Note: The (.95mm) reluctance gap spacers salvaged from the disassembly process are shown in the "component identification image" for completeness of presentation only --- Based upon core material properties and desired output current, optimal operation requires development of reluctance gaps consistent with the inequality: 0.25mm < Gap < .5mm -- To this end 0.4mm (nominal) PTFE sheet stock will be used.

Tasks:
1) Cut two small disks of PTFE having maximum diameters (as a practical matter, major axises) slightly less than that of the form piece 'ends'...
2) Check actual spacer thickness with a caliper -- then verify with a mechanical micrometer.
3) Very lightly smear one side of each spacer with electronics grade RTV.
4) Place each spacer ('siliconed' side down) flat upon each form piece end (inside each polyolefin sleeve).
5) Via firm tamping with a pencil eraser or similar implement assure that the RTV film 'tacks' the spacers to the form piece ends...

Images showing representative spacer and measurement of thickness:
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http://forum.allaboutcircuits.com/attachments/airgapcal-jpg.101725/

http://forum.allaboutcircuits.com/attachments/airgapmic-jpg.101728/

Image showing correct pre-assembly placement of spacers:
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http://forum.allaboutcircuits.com/attachments/airgapinplace-jpg.101727/


Step 14) Assemble LOPT

Tasks:
1) Tack elastic cushions and form standoffs to frame then position as shown:
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http://forum.allaboutcircuits.com/attachments/loptframechoks-jpg.101732/


2) Verify that the reluctance gap spacers are fast to the form piece.
3) Hold the frame ligature in lengthwise apposition with the utmost facet of the form's EHT winding leg. (i.e. the leg carrying a double thickness of polyolefin).
4) Carefully place the EHT winding assembly over the form piece leg and ligature such that the shoulder stirrup engages the the form piece as shown below:

Form ligature in pre-assembly position:
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http://forum.allaboutcircuits.com/attachments/asm1-jpg.101729/

Views of EHT winding, form piece and form ligature in intermediate state of assembly.
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http://forum.allaboutcircuits.com/attachments/lopt_preasmby-jpg.101731/

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http://forum.allaboutcircuits.com/attachments/loptpartialasmby-jpg.101735/

Slowly press opposite form piece into place allowing time for displacement of air from the polyolefin tubes.
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http://forum.allaboutcircuits.com/attachments/loptpreframe-jpg.101737/


5) Install transformer assembly into frame such that the ligature strap ends extend through the 'ears' of the frame.
6) Very carefully but firmly clamp assembly preparatory to fastening...
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http://forum.allaboutcircuits.com/attachments/loptpresoldered-jpg.101739/


7) Solder ligature ends to frame
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http://forum.allaboutcircuits.com/attachments/loptpostsoldered-jpg.101736/

Step 15) Install lateral insulator

Tasks:
1) Form a carotid of 0.093" (AKA "93/1000'ths") PTFE sheet stock as per item #1 in the image (immediately below):
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http://forum.allaboutcircuits.com/attachments/lopt_partsnum-jpg.101730/

2) Size, shape and fit the insulator to the EHT winding assembly in a manner consistent with the following images but do not apply adhesive at this time.
Note that the insulator must trimmed to closely fit the shell and extend beyond the distal aspect of the EHT winding by at least 1 cm.

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http://forum.allaboutcircuits.com/attachments/final-jpg.101745/

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
http://forum.allaboutcircuits.com/attachments/strikeshldside-jpg.101748/

3) Having properly formed the insulator, 'de-gloss' one side of same using '00' grit emery cloth/paper.
4) Apply liberal quantities of electronics grade RTV silicone to the appropriate surfaces of the EHT winding assembly and the entirety of the 'sanded' side of the insulator.

5) Attach the insulator to the EHT winding assembly as shown in the above images
6) Apply an excess of electronics grade RTV to the exposed side of the insulator and adjacent areas of the EHT winding assembly...
7) Distribute the RTV over the insulator and EHT winding assembly surfaces such that an interlocking bond is established.
8) Position the LOPT 'insulator up' then allow at least 48 hours curing time.



To be continued/refined via edit...

Best regards
HP