Mains Transients from vacuum cleaners, showers, tumble dryers etc

[ocset]

hi

Do you think showers and vacuum cleaners and tumble dryers  produce significant  mains transients?

This website..
https://www.blumelabs.com/faq
..says they do..

Surely the prolifery of multiple  other connected mains devices and their capacitor banks/MOVs  will damp away any transient spikes?

Most standard LED bulbs we have tested do not have basic transient surge protection. When a large domestic appliance is operating, such as a tumble dryer or vacuum cleaner, they generate large voltage spikes or transients which can blow other devices in the same building, such as light bulbs. If you operate your tumble dryer, vacuum cleaner and electric showers when such bulbs are on, don’t expect them to survive for long.

Also, the same page says that high temperatures kill light bulbs....i can appreciate with electrolytic capacitors that applies...but surely not for other components?..as long as they are kept within their temperature spec.

Is it true that high solder joint temperatures above 110degc can eventually go open circuit?

[T3sl4co1l]

"Prolifery"?

Suppose that everyone else is as cheap as you are.  Then what?

There are regulations for a reason.

Tim

[coppercone2]

everything degrades and migrates more and stresses come out when stuff is hot. silicon ages too.

light bulb will lose half its life time at a few extra volts from what I know. filament.

Also, FUCK CHEAP LIGHTS.

I installed a god damn flood light from ebay over my drive way (had to rewire the entire attic). It was a epic piece of shit that looked like your being flashed. Hey baby look under my trench coat, ITS A FUCKING ARC WELDER. I put some film on it to mask out the unpleasant colors, then about 2 days later some LED burn out. I just about climbed on my roof and yelled DAMN YOU TREEZ

No doubt a piece of shit. Now I need to climb a ladder and replace it. 

[coppercone2]

I did however put a LED light on my drill press. Not sure if with as a extra TVS but it still works, however not used frequently.

From what I read on this forum resitive heaters sometimes can spark. 

[dmills]

Old style universal motors are **NASTY** if not suppressed, and very common in vacuum cleaners and some food processing applications.

Most other things are induction motors that are not anything like so RFI happy, but can make for a nasty mess if contactors are used without suppression.

Really however, the mains is hardly an unknown thing, and everyone designing gear to hang on it should be designing for 'sufficient' reliability to meet market needs given the expected nastyness. Who knows there may even be standards documents and app notes that tell you what to expect, a power supply specialist would be able to tell you about those?

Have a look at LED life Vs temperature curves sometime if you think caps are a problem.... Also, semiconductors have an electromigration issue that more or less follows Blacks Eqn, and LEDs are semiconductor junctions.

[rstofer]

And despite the trash and glitches on the mains, everything works.  Large screen TVs, network gear, computers, audio/visual equipment, literally everything.  Somebody must be doing something right.

[dmills]

Yep, I think there must be **SOME** power supply designers out there that actually know their trade.

A few of them may even have done constant current supplies for LED kit that do not suck, but that may just be a vicious rumour.
Regards, Dan.

[T3sl4co1l]

Yeah, nice thing about mains transients is, if you're not trying to be an overly clever idiot*, it basically comes down to spectrum and voltage or power or energy.

*Which is all too common in these days of computer-based everything, with hidden and unintended states accessible through very specific (rare, but often not impossible) sequences.  EMC manifests in many possible ways; inputs momentarily getting tapped is a common occurrence.

And spectrum comes down to filtering, and voltage or energy to clamping, and power to ratings.  It's dumb and easy, so much less trouble than trying to be clever about it.

Tim

[dmills]

I sense someone who has been bitten by the recent tendency to put significant amounts of state machine in switchmode controller chips that should have at most a few flipflops and a monostable or so?

State spaces for this sort of thing should be small, and fully covered by recovery logic, but they are all too often these days, large, sparse and NOT covered by recovery logic for illegal states.

I am guessing TI as the offending party, but it could be almost any of 'em.

Something lossy in series, and something capable of clamping in shunt, that's the way you do it, no need to get clever.

Regards, Dan.

[Benta]

"showers"?

[NiHaoMike]

"showers"?

Someone had the idea to build an instant water heater right into the shower head.

[joeqsmith]

hi

Do you think showers and vacuum cleaners and tumble dryers  produce significant  mains transients?

I guess that depends on what significant means to you.   I can tell you that I have not lost and LED bulb to a transient except when we were hit by lightning last summer.   It seems the higher powered LEDs run hot and people put them into standard fixture which may not allow them to dissipate the heat.   I've taken apart a few that have failed.  One was a cap that had failed from being heated.  A couple have had a mechanical joint that failed.  One used cooling fans that had failed, causing it to overheat.  I have repaired some of these and put them back into service.   

[Benta]

"showers"?

Someone had the idea to build an instant water heater right into the shower head.

That's one of the scariest devices I've ever seen...   

[IanB]

Do you think showers and vacuum cleaners and tumble dryers  produce significant  mains transients?

Some of us may be old enough to remember how running the vacuum cleaner filled the television picture with snow?

Whether all that emitted energy was actually dangerous to other electronics remains an open question. In the old days I don't remember anything being harmed by it. It probably only affected televisions and radios because it was being picked up by the antenna circuitry.

[T3sl4co1l]

I sense someone who has been bitten by the recent tendency to put significant amounts of state machine in switchmode controller chips that should have at most a few flipflops and a monostable or so?

That's a recent topical example, but more generally, it's seen at all levels of development.  I'm doing EMC mitigation on a soon-to-release product, that they wouldn't be having nearly so many problems with if they used one MCU (I think an STM32F0 would be enough for what they're doing) and a bunch of logic gates and transceivers to fan everything out.  Instead they made essentially an ARM PC (complete with PCIe expansion slots), with multiple levels of vulnerability both in EMC terms, and likely in software terms.

Tim

[ocset]

And despite the trash and glitches on the mains, everything works.  Large screen TVs, network gear, computers, audio/visual equipment, literally everything.  Somebody must be doing something right.

Thanks, thats right,  though the site referred to in the top post seems to say that generally, light bulbs dont work...at least not for very long, and its due to transients.
When I look inside other devices, i notice they dont have much special stuff for transient protection......the filter, the big electrolytic, and usually no more than a single 10mm MOV.
So i am wondering, are transients over-exaggerated.?

Seriously, if i put the hoover or shower  on, and then connect my diff probe across live and neutral, am i going to see anything other than 50Hz sine?

[chris_leyson]

IEC 61000-4-4 calls for 1kV for basic EFT testing, reidential environment, but you can test at up to 4kV.

So i am wondering, are transients over-exaggerated.?

Nope, as Tim has already said "There are regulations for a reason". As part of my job I design small flyback supplies and if they don't pass EFT at 4kV then they get rejected never to used again. EDIT: One controller chip actuall blew up at 3kV, I won't ever be using those again. I've had some designs work at 7kV EFT only because the generator wouldn't manage 8kV.

EDIT: Had a washing machine that went through four controller boards in less than five years and at one time the service engineer advised putting a transient suppressor at the wall socket, wtf. Perhaps they only tested at 1kV but I won't be buying their products again. I guess it's one of the hazards of living in a house supplied by overhead lines but now that they've been replaced by underground cable it's probably less of an issue.

[IDEngineer]

In my son's racing drone community (I'm talking international here, so folks from everywhere), there's a persistent rumor that hanging a bit fat electrolytic cap across the LiPo battery "kills noise" and suppresses transients.   Meanwhile, my son installs an actual Littelfuse tranzorb, plus small ceramic caps at the power inputs to each PCB on his aircraft. Guess which approach has proven the most reliable?

Folks also believe that those big fat electrolytics provide makeup power under short-term heavy load conditions (such as extreme acceleration). These aircraft can burst 150+ amps from a LiPo, and both he and I have tried to explain to people that the ESR of the battery is WAY lower than the ESR of the electrolytic cap... but do they listen? AND run the numbers, just how much actual energy is available from that electrolytic as compared to the LiPo even if the ESR wasn't dissimilar?

There are some AMAZING transients coming off those three phase motors. The supply rails are a study in noise. And just imagine what happens when they hit a gate when the motors are spinning at 10K RPM... that field collapse is going somewhere, in almost zero time. dI/dT where dT approaches zero can be a very large number.

You won't experience these extreme cases in most home-based, mains-powered motors but the principles are the same.

[vk6zgo]

Transients, by their very name, are "transient", with a low duty cycle, so the total energy available is quite small.
They are also rich in high frequency components, which will have trouble passing through most power supply filters.
Vacuum cleaners & clothes dryers have coexisted with electronic equipment for years.

[coppercone2]

sure but keep in mind those are just 1500W-3000W.

I think we all assumed the OP meant industrial?

[IDEngineer]

I think we all assumed the OP meant industrial?

I did not.

[coppercone2]

what the hell is a tumble dryer? I thought its for drying/cooking sand/ferrite?

[IanB]

what the hell is a tumble dryer? I thought its for drying/cooking sand/ferrite?

Please explain the question. I cannot make sense of it.

[coppercone2]

I thought he meant one of those kiln stirring things for preparing powders for sintering. I guess he means a clothing dryer. I saw tumble dryer and I just associated it with powder metallurgy/ceramics manufacturing.

[IanB]

Then I guess hot air tumbling clothes driers aren't called tumble driers everywhere in the world then? That is the only name for them where I am from...