EEVblog #1182 - Mains Interference Simulator Teardown - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: February 22, 2019, 12:44:50 am
content: A look inside a Swiss made Schaffner NSG200E Mains Interference Simulator after it released the magic smoke.A very unusual bit of kit that tests products for mains line interference like lightning strikes, transients, and dropouts.May involve alien crop circles.

author: Ketturi
author_rank: Regular Contributor
timestamp: February 22, 2019, 01:27:10 am
content: Interesting piece of a test kit. It is always wonderful to see specialized equipment just build for specific case, often in small production runs, assembled by hand. Similar eurocard rack enclosures were popular base for one-off prototypes or small volume products where cost was not an issue.I would have bet that smoke came from those translucent plastic filtering caps, not only because they often fail when aging but also due Daves reaction to smell of the smoke. Once you smell it, you will think twice before connecting old devices into mains. They do after all, release a lot of smoke with quite gagging odor. The problem is with those type of caps that when hard plastic ages, it develops cracks that cause moisture to seep in that turns them conductive, and when high energy source is connected over them, heating effect handles the rest. Follow your nose, it is actually sensitive tester to, lets say, date vintage electronics, or to locate blown components.Dark marks on that big choke also do look alarming, but I have seen similar marks in fully working transformers, where lacquer or waxy potting compound has turned to brown due heat and old age. It is also common to see similar drip marks on transformers where coating was applied a bit hastily during manufacturing. Still, I would test it with megger to be sure.

author: lordvader88
author_rank: Frequent Contributor
timestamp: February 22, 2019, 03:25:29 am
content: Wow the only thing I can ever find for free or low cost is modern CRT TV's. And I don't need to salvage from them anymore. I wish I had really old CRT TV's to actually how TV works.What happens to all the cool e-waste here tho? IDK, the dump or metal scarp yard I guess.

author: TurboTom
author_rank: Super Contributor
timestamp: February 22, 2019, 06:52:23 am
content: Seems like you must have some funny issues with gravity in "down under" if the CM choke's varnish melts and forms drops in a horizontal direction...As I interpret it, there's nothing wrong at all with the CM choke, the wire is okay (can't almost bear watching Dave scratching the wire with the screwdriver...), the protective varnish having formed these drops is just the result of manufacturing. It's probably a high viscosity epoxy that the OEM used to pot the inductor, maybe afterwards heat-cured which also caused the slight tanning of the solidified resin. I've seen much worse looking inductors that were completely okay, especially if wound with highly heat resistance enameled wire (polyimide insulation).I rather believe the smoke escaped from the big potted block next to the big-ass inductor, or maybe even the mains input filter... some models of Schaffner filters are notorious for spectacular pyrotechnical effects... Maybe use the EE's most important tool...the nose...for identifying the culprit. It would be a shame if this unit couldn't be fixed.CheersThomas

author: Barny
author_rank: Frequent Contributor
timestamp: February 22, 2019, 08:12:16 am
content: Thanks for bringing the picture of nude virgin gray-beards back in my mind after I sucessfully got rid of them.Joke asside.I would give the old translucend caps a close look.8 of 10 times I set them under power (after desoldering them out of old gear) they makeing a good light-show.At my work, they changed all of this type of caps after they nearly set fire on the main-building.This type of caps is the reason why every bit of gear has to be checked from the spark-cobblers bevore switcheing it on.

author: AndersJ
author_rank: Frequent Contributor
timestamp: February 22, 2019, 08:38:07 am
content: I would check the Rifa caps,on the board and inside the mains filter.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: February 22, 2019, 11:20:06 am
content: Cool video, I would strip all the copper off that filter choke and sell it for scrap metal

author: coppice
author_rank: Super Contributor
timestamp: February 22, 2019, 11:36:43 am
content: This is hardly a rare or niche piece of equipment. Pretty much everything mains powered is tested with this type of equipment these days. If it only goes to two point something kilovolts its pretty useless these days, as people usually need to test to 4kV or 4.5kV. A lot of stuff for dry climates, like the Australian desert, need to be tested to 8kV or more.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: February 22, 2019, 07:50:51 pm
content: The point of the screwdriver @08:08 points to an external discolored blob on the outermost part of the plastic housing.If there was anything wrong with that huge common mode filter it is not because of a black spot on the outside of the plastic frame of the thing.Quote from: johnlsenchak on February 22, 2019, 11:20:06 amWhen my brother went to work on a monday he found the results of such thoughts.EUR 10000 of damage to steal EUR 200 worth of copper from a power distributer cabinet.Please Dave, try to find a good home for the thing. Put it on Ebay or something for a minimum of AUD 100 exclusive shipping and see what happens.

author: nixxon
author_rank: Frequent Contributor
timestamp: February 22, 2019, 07:53:28 pm
content: Quote from: coppice on February 22, 2019, 11:36:43 amHell, why not test it for an Aussie 1MV!

author: nixxon
author_rank: Frequent Contributor
timestamp: February 22, 2019, 08:03:17 pm
content: Quote from: Doctorandus_P on February 22, 2019, 07:50:51 pmThis shit happens pretty often. Thieves, sometimes from abroad, have an impared cost-benefit judgement. The other day somebody stole copper pipes worth $50 in the capital of Norway (Oslo) resulting in thousands of liters of oil spilling out into a river...https://translate.google.com/translate?hl=en&sl=auto&tl=en&u=https%3A%2F%2Fwww.aftenposten.no%2Fnorge%2Fi%2FMgy0dK%2FTyver-stjal-kobberror--flere-tusen-liter-fyringsolje-kan-ha-lekket-ut-i-fjordenIn case linking to the Norwegian newspaper doesnt work, here is the article's ingress: "- Emergency services are at a company at Ulven. From there, it has probably leaked several thousand liters of heating oil down into the ground and out into the Akerselva river following the weekend. Oslo fire and rescue service has stopped the leak, and is working to suck and collect the oil, "

author: EEVblog
author_rank: Unknown
timestamp: February 23, 2019, 12:35:50 am
content: Quote from: Barny on February 22, 2019, 08:12:16 amYes, 2nd video coming...

author: joeqsmith
author_rank: Super Contributor
timestamp: February 23, 2019, 03:11:34 pm
content: Been waiting for you to show this thing after you pulled it from the dumpster. Enjoyed the video.

author: Towger
author_rank: Super Contributor
timestamp: February 23, 2019, 04:48:44 pm
content: RIFA RIFA RIFA... Actually those Schaffner mains input filters are also ticking time bombs and should be replaced on older equipment, especially when run at 240v.BTW. Did you ever sort out the apparent lack of a RCD in the new lab.?

author: Fungus
author_rank: Super Contributor
timestamp: February 23, 2019, 05:29:31 pm
content: Quote from: nixxon on February 22, 2019, 08:03:17 pmThey don't care what it costsyou, so long as it benefits them.

author: coppice
author_rank: Super Contributor
timestamp: February 23, 2019, 05:53:31 pm
content: Quote from: Doctorandus_P on February 22, 2019, 07:50:51 pmSome large customers for fibre optic cables require that the entire length of the cable is printed with "This cable contains no copper" in the relevant local languages, to reduce the incidence of this kind of damage.

author: Fungus
author_rank: Super Contributor
timestamp: February 23, 2019, 06:41:12 pm
content: Quote from: coppice on February 23, 2019, 05:53:31 pmMaybe they could print that on the copper cables, too. It would reduce damage/theft to zero.

author: glarsson
author_rank: Frequent Contributor
timestamp: February 23, 2019, 06:47:52 pm
content: Only if the thieves can read and process the information.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 23, 2019, 07:32:40 pm
content: The flattened wire for the choke is not that unusual. It allows to wind the coil with less space lost. So it can be found at larger cross section - the extra cost is more on carefully wind it to use the advantage than the wire itself.The cross section is what it takes to safely take 16 A without cutting costs or having a fan.I would too be surprised if the smoke came from the choke.

author: floobydust
author_rank: Super Contributor
timestamp: February 24, 2019, 08:48:38 pm
content: The big CM choke does see kV impulses, so it may have arced from winding to core. Nothing a little Kapton tape would not fixI have also seen loose metal chips get in windings and jab the wire insulation, causing breakdown.That DIP IC that was loose in the socket, seems like the unit got dropped hard.