EEVblog #1182 - Mains Interference Simulator Teardown

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.

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[Seegalgalguntijak]

LOL @ "you don't see many Elkos" - after all, Elko is just an abbreviation of "Elektrolytkondensator", which means electrolytic capacitor. And those are basically everywhere ;)

[maxtorque]

The large input filter and Common mode choke make sense when you realise that this device must keep the DUT nicely isolated, both in terms of receiving any perturbations from local noise on the mains used to drive the test, and to prevent the noise and surges it actually injects into the DUT from coupling back up the supply and into the mains powering the unit!

[douro]

I didn't know Schaffner made these. They are certainly one of the leading manufacturers of noise filtering equipment, and the ubiquitous integrated noise filter we're all familiar with was an original invention of this company.

[LittleRainGames]

That dumpster is a gift that just keeps on giving

[AZREDFERN]

My guess is it let the smoke out before they threw it away. Then the contact between the exposed coils oxidized, pushed apart, and created an air gap. Then it worked fine for you until you put any kind of load on it.

[richfiles]

At my old job, we had a massive California Instruments rack mount 90° 2phase inverter that could generate 400 Hz outputs anywhere from a few volts to a few hundred volts. We used it for testing motors and synchros intended for Defense and aerospace applications. The inverter was far too large for me to salvage intact, but I did salvage the old waveform generator from it when we scrapped it. The chokes and transformers in it put this to shame... Though at least it's wires were standard round solid copper wire, and not freakin' bus bars! WOW! Your bit of kit wins in that department!

[CraftAero]

... and here's me testing my audio power supplies by plugging in circuit and cycling incandescent/flourescent lights, vacuum cleaners, blenders, microwave ovens, etc.

[Glimmrelais]

KACO is an old german company - Kupfer Asbest & Co. They made vibrators for vibrator power supplys and relays in the past, nowadays they only make sealing elements. I have a really old 12V DC to 220V AC inverter with a massive vibrator cartridge made by KACO, a wonderful thing that wheighs a ton and produces a nice humming sound when energized :)

[gregadams]

Calibration Not Required. That needs to be a t-shirt.

[MaxKoschuh]

8:24 it is very unlikely that there's only one tiny hot spot on a large coil like that
10:12 one of the RIFA caps might have a hidden vent hole for magic smoke

[geronimostade]

The 400 Hz tab is most likely for aviation based testing. They usually will have 115 Volts by 400 HZ driven by the engines.

[__qqq__]

It let the smoke out because you turned it on before taking it apart :)

[brucepickess]

Hi, I have used this equipment for post office pre submission testing to meet post office security approval. The testing was on mains powered electronic postal franking machines. These machines effectively hold post office revenue . And very stringent testing was required to ensure that there could be no corruption or possible fraudulent attempts to defraud the postal authorities. Testing was to UK, US, and European postal authoritie standards. I also did ESD testing using Schaffner equipment. I worked for a company called Neopost which at one time came under Alcatel.

[cambridgemart]

Perhaps it was tossed after failing an insulation test due to a breakdown in the CM choke.

[DasMrOSi]

Elko is short for Elektrolyt-Kondensator (Electrolytic Capacitor)

[lp]

Maybe the loose IC popped out when the unit was tossed. Could the meltdown been caused by that?
Anyhow, we see an old rule again: When obtaining gear in an unknown state, always first open it and check for anything that could be wrong! That rule exists for that very reason!

[sickparrot]

Brings back memories, we used one of those bringing our range of PLCs up to EN specs in the late 80's

[mrnmrn]

Dave! Please check those RIFA paper EMC caps at 10:21, I'm pretty sure they are the culprit, the choke should be fine. The black spot is probably some paint, dissolved from the core into the potting laquer. Also the ITT cap might be a PIO, and if so, it should be replaced. There's an other RIFA paper cap in the injection module at 17:08 on the back of a switch.

[timmgiles]

Loving the R&S PSUs in the background :-) Another interesting teardown.

[williamsquires]

Check the resistance between the windings of that common-mode choke - I can’t see it failing due to a short in one of the windings themselves; they’re not operating as a step-up/down transformer, so they’re not rated to have mains across them. It’s also possible that something else failed, not the choke; the crud might just be something that got spilled in there and dried up.