In my case, SWAG = best guess (how I heard it used growing up in small town USA, along the lines of Wikipedia's entry).
Cheers, Adam in Atlanta [email protected] On Tue, Jun 25, 2024 at 8:29 AM James Pawson (U3C) < [email protected]> wrote: > Could someone define the acronym SWAG in this context please? > > > > Something With Air Gap? > > > > All the best > > James > > > > James Pawson > > Managing Director & EMC Problem Solver > > > > *Unit 3 Compliance Ltd* > > *EMC : Environmental & Vibration : Electrical Safety : CE & UKCA : > Consultancy* > > > > www.unit3compliance.co.uk | [email protected] > > +44(0)1274 911747 | +44(0)7811 139957 > > 2 Wellington Business Park, New Lane, Bradford, BD4 8AL > > Registered in England and Wales # 10574298 > > > > *Office hours:* > > *Every morning my full attention is on consultancy, testing, and > troubleshooting activities for our customers’ projects. I’m > available/contactable between 1300h to 1730h Mon/Tue/Thurs/Fri.* > > *For inquiries, bookings, and testing updates please send us an email on > [email protected] <[email protected]> or call 01274 > 911747. Our lead times for testing and consultancy are typically 4-5 weeks.* > > > > > > > > > > *From:* Adam Dixon <[email protected]> > *Sent:* Tuesday, June 25, 2024 1:24 PM > *To:* [email protected] > *Subject:* Re: [PSES] dielectric strength question > > > > SWAG #2: non-uniformities in materials + multiple breakdown mechanisms > make it difficult to model. Mica shows up in 1940's vintage literature. > Here are some interesting papers that I perused after Rich posed the > question: > > > > https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=9079498 > Space change behavior in cross-linked polymers > > https://onlinelibrary.wiley.com/doi/10.1002/app.49379 > Touches on different breakdown mechanisms (see Figure 3; also the Figure 2 > reference may be worthwhile but I haven't tried accessing it) > > https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764431/ > electron injection and avalanche breakdown process > > > https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=65f577afe99e3253e7e3f38054ce9ea49b16a636 > Electromechanical breakdown mechanism but also states "The exact cause for > the observed behavior remains to be investigated" > > https://apps.dtic.mil/sti/pdfs/ADA635433.pdf > Paschen Curve anomalies (for consideration of gas dielectrics) > > https://www.osti.gov/servlets/purl/1656858 > > Describes influence of polymer chain ends (Figure 1 is a good illustration) > > > > > > Cheers, > > Adam in Atlanta > > [email protected] > > > > On Mon, Jun 24, 2024 at 11:00 PM Patrick <[email protected]> wrote: > > just a SWAG... perhaps dielectric strength is dependent on volume, and > the increased 'thickness' is assumed to be > thickness-for-a-constant-surface-area. If that's the case then an > increasing thickness is also an increased volume which also increases > available charge carriers, reducing breakdown voltage. > > A test of my SWAG would be to incrementally increase dielectric thickness > and determine if breakdown voltage eventually finds a minimum and then > begins to increase with thickness. > > interesting question. > > > > On Sun, Jun 23, 2024, 13:32 Richard Nute <[email protected]> wrote: > > > > Why does air (or any insulating material) have decreasing dielectric > strength, kV/mm, with increasing distance through the dielectric > substance? Assume homogenous field. (I have assumed the dielectric > strength was constant for the material.) In other words, what is the > physical basis for the non-constant dielectric strength clearance tables > in various safety standards? (I have yet to find the answer from the web.) > How can I predict the dielectric constant for a given distance through > air (or any insulation)? > > Charles J. Fraser, in Mechanical Engineer's Reference Book (Twelfth > Edition) > <https://www.sciencedirect.com/book/9780750611954/mechanical-engineers-reference-book>, > 1994: > > If the potential difference across opposite faces of a dielectric material > is increased above a particular value, the material breaks down. The > failure of the material takes the form of a small puncture, which renders > the material useless as an insulator. The potential gradient > <https://www.sciencedirect.com/topics/engineering/potential-gradient> > necessary > to cause break down is normally expressed in kilovolts/millimetre and is > termed the ‘dielectric strength’. The dielectric strength of a given > material decreases with increases in the thickness. Table 2.2 gives > approximate values for some of the more common dielectric materials. > > Table 2.2. Dielectric strength of some common insulators > > *Material* *Thickness (mm)* *Dielectric strength (kV/mm)* > Air 0.2 5.75 > 0.6 4.92 > 1.0 4.36 > 10.0 2.98 > Mica 0.01 200 > 0.10 115 > 1.00 61 > > Thanks, and best regards, > > Rich > > > ------------------------------ > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. 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