Would you trust your life to this?

Thread Starter

Ian0

Joined Aug 7, 2020
3,756
https://www.allaboutcircuits.com/ne...reakers-extract-dc-from-ac-without-magnetics/
This e-mail from AAC arrived in my inbox the other day, and I still can't make any sense out of it.
Extracting DC from AC without magnetics - well - that's easy - it's called a diode. But extracting DC from AC without rectifiers and smoothing capacitors?
The whole thing seems like a bunch of marketing nonsense to me, and they are expecting us to replace our MCBs with these things that can supposedly decide within a millisecond whether an overcurrent situation is a fault of just an inrush?
Give me a fuse any day.
 

Thread Starter

Ian0

Joined Aug 7, 2020
3,756
Ah, those were the days when you had to make sure you kept a couple of rolls of the right gauge on hand at all times! :D
Remember those little cards of fuse-wire in 5A, 15A and 30A that you kept on top of the fuse box? I'm sure MCBs and modern fuses are rather better than semi-enclosed-rewirable fuses, but what is this device they claim they have invented?
 

MaxHeadRoom

Joined Jul 18, 2013
23,912
Remember those little cards of fuse-wire in 5A, 15A and 30A that you kept on top of the fuse box?
Remember them well, also we had pay as you go meters, (UK) Essential to keep a two shilling piece handy in case the power timer ran out.
Electric and Gas.!

1630616838330.png
 

SamR

Joined Mar 19, 2019
3,607
Here in the states, it was screw in glass plug fuses. You put a penny under them when they blew or a dime if you didn't have a penny. Burned down a lot of houses...

1630619011337.png
I don't like being out on the "Bleeding Edge" of technology. I prefer to let others take their lumps while all the bugs are getting ironed out. But then I am a bit of a Luddite...
 

nsaspook

Joined Aug 27, 2009
8,902
https://www.allaboutcircuits.com/ne...reakers-extract-dc-from-ac-without-magnetics/
This e-mail from AAC arrived in my inbox the other day, and I still can't make any sense out of it.
Extracting DC from AC without magnetics - well - that's easy - it's called a diode. But extracting DC from AC without rectifiers and smoothing capacitors?
The whole thing seems like a bunch of marketing nonsense to me, and they are expecting us to replace our MCBs with these things that can supposedly decide within a millisecond whether an overcurrent situation is a fault of just an inrush?
Give me a fuse any day.
“We are pleased to announce this highly disruptive upgrade to the world’s old circuit breaker technology,”
The magic word is 'disruptive'. I'm sure I remember seeing that word in every engineering book I've read.
1630619986128.png
 

MisterBill2

Joined Jan 23, 2018
9,801
I looked at that link and it is a great example of weasel-wording!! Based on the description that it uses a mosfet, it seems like it must include a switching circuit to just pass a small segment of one polarity of a sine wave. Quite an interesting idea, but certainly over-complex, and subject to a wide variety of serious failure modes.
I suggest not waiting until the device comes to market, because your project will be delayed a very long time. Just because something can be done does not mean that it can be produced in quantity at a reasonable price and an adequate production yield.
 

Thread Starter

Ian0

Joined Aug 7, 2020
3,756
I'm not holding my breath either. I think that the most serious potential failure is if the MOSFET fails short before it manages to switch off the fault current that it is trying to break.
I can't imagine it being possible to make a 16A breaker this way, as it would need the same heatsinking as a 16A SSR.
Generating a 5W low-voltage supply by using a small segment of a mains sinewave needs quite a large current very briefly, which suggests that there might be some interference caused which would need magnetics to filter out.
 

MisterBill2

Joined Jan 23, 2018
9,801
The details were very sparse in that link, while the hype was burdensome and plentiful. And based on what was left out, it almost seems like a scam or an April 1 posting..
 

dcbingaman

Joined Jun 30, 2021
497
Here in the states, it was screw in glass plug fuses. You put a penny under them when they blew or a dime if you didn't have a penny. Burned down a lot of houses...

View attachment 247135
I don't like being out on the "Bleeding Edge" of technology. I prefer to let others take their lumps while all the bugs are getting ironed out. But then I am a bit of a Luddite...
That is literally what happened to my Grandfathers house over 40 years ago. My father bought it. It burnt down shortly after he bought it. My grandfather had placed a penny in the back of the fuse to avoid the fuse blowing! House fire was pretty much a guarantee it was just 'when' not 'if'.
 

dcbingaman

Joined Jun 30, 2021
497
If it fails to stop a short and burns down a house, this company is going to be paying out big in liability suits. The lawyers will jump on it.
 

MisterBill2

Joined Jan 23, 2018
9,801
Maybe I missed it but the company seems to have zero actual commercial products using this technology.
That was part of my point! Lots of fancy talk but no actual description of the mechanism of the process. To this engineer the words did not even make much sense. They were just fancy phrases

And another point, what is so bad about rectifiers? Or regular switching mode power supplies? AND, why does a circuit breaker need a DC power supply anyway? I have seen published circuits for "electronic fuse" protection schemes, but they were not competitive with the simpler mechanical systems for most applications.
 

Thread Starter

Ian0

Joined Aug 7, 2020
3,756
I also have to say that it's a poor piece of journalism. If all she is going to do is quote the press release verbatim, why do we need journalists? Isn't the point of journalism to disseminate the technical information for the general public? Is strikes me that she didn't understand the press release either, and didn't question it, and she claims to be Editor in Chief of All About Circuits, with a degree* in English and Philosophy. Is there anyone anyone at all who is technically qualified on staff?

*It just says "studied at" so I assume she passed the exams.
 
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