By using insanely high switching frequencies. Ten or fifteen years ago, I had a client who wanted to build a 24V, 30A switcher for an on-board wheelchair battery charger; three months later we abandoned the project, because even the guys from the company who sold the magical chip weren't able to teach me switcher design. The chip was rated for 1 MHz. A MEGAHERTZ! In a SWITCHER! =:-O These days, I wouldn't be surprised if they're approaching gigahertz switching frequencies - heck, look at microprocessors these days, that are big enough to be their own antenna!
Have you seen any of these magical mysterious power supplies kill anybody, or even let the magic smoke out?
Money is merely a scorekeeping device. It's inanimate. It just sits there, until somebody uses it to buy something. My Mom, bless her, was very specific in teaching me that it's the LOVE of money that's the root of all evil.
LOVE of money is the root of all evil.
That's LOVE of money as a replacement for love of life, love of pepole, love of love, love of reality, and so on.
--
Love,
Rich Grise
First Member, Church of the Neodruid
In truth, it\'s denial that\'s the root of all evil, but that\'s advanced
metaphysics - for further information, please visit
http://www.godchannel.com
--
Inadequate and Deceptive Product Labeling:
Comparison of 21 Power Supplies
Test Results In Detail
Let\'s not beat about the bush here. The 21 power supplies we tested
are rated by their manufacturers at between 300 and 520 watts. Our
tests showed, however, that only 15 of them actually met their
specifications....
Even if you don't get the fireworks you can get crashes, data corruption etc.. See the above article which had one supply dropping the 12V line to < 6V. I'm sure the typical $99 200GB drive is going to love that.
Yes, even the hassles of restoring a system that has fried itself is probably worth more. Assuming you have full backups.
Best regards, Spehro Pefhany
--
"it\'s the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
I had the same thing happen. Fortunately I keep good backups so I didn't lose anything.
But even the best power supply can fail, or an external device could develop a short between voltages. I've been thinking of a simple crowbar that could be added to the +12V and +5V supplies. Have it short the voltage if a failure raises the voltage above a limit, and plug it in a spare drive power connector to prevent damage if anything goes wrong.
I don't know how power supplies react to a short. If they respond by trying to increase the other voltages, it mmight be necessary to crowbar all the voltages at the same time. I'd probably do it just to be on the safe side.
One problem would be indicating which voltage triggered the circuit so you could troubleshoot it. This might take a small battery powered circuit to store the conditions at failure, and a switch to light the corresponding led to examine the failure.
This could be made real cheap. Anyone know a source for inexpensive 50A or 100A scr's?
Set up a Holding Company, the Holding Company Import loads of chinese ripoffs and sell them to a group of Distributers in the form of Limited Companies, who, in turn, will put whatever sticker on that sell the unit - nevertheless they do not make much profit because the markup is with the Holding Company.
Eventually, someone/something gets hurt and Distributor gets sued; Distributor goes bankrupt; Holding Company gets to keep the profit because
*it* never did anything wrong, it just Imported the stuff.
*WHY* They can get away with this is the Interesting Question!
Some (most?) PC power supplies already have crowbar or some other kind of overvoltage protection built in. For example (this is a beefy server supply):
formatting link
See table 3.5.2.
Here's another:
formatting link
In fact it's required in the Intel's Design Guide:
formatting link
See section 3.4, although the Enermax supply does not meet the overvoltage specification on the 3.3V line.
I always liked section 3.1.5 as well. What exactly constitutes "excessive smoke", I wonder. ;-)
Teccor has some 50A SCRs in TO-3P for about $5 US each one-off (only about $1.70 for 40A in TO-220, so much better value). Much bigger and you're probably into stud package and more money.
Best regards, Spehro Pefhany
--
"it\'s the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
Many years ago I had a no-name PC Power supply take out a motherboard, both hard disks, all the cards, and even the keyboard. Since then I have never powered up a new system without first replacing the PS with one from PC Power and Cooling, which I consider to be the maker of the best PC power supplies available.
..and my data is worth more than both put together. :)
My favorite misquote is "Pride goeth before a fall". The correct phrase is "Pride goeth before destruction, and an haughty spirit before a fall" (Proverbs 16:18).
The physical money are only reflections, copies of mental money, well-being, a feeling of power over yourself, and over others too, if they are scared.
The love of the feeling of money. The satisfaction, the peace in your soul, the social dominance, the power of a powerful mind.
The taste is corrupting. The experience of becoming both strong and happy, enjoying good treatment everywhere, is difficult to question. It is a very convincing feeling. Or we look at the situation from a faulty angle.
Maybe we all have sick souls, been trained to live "in the fear of God" for thousands of years, this has affected the human mind, and affects each mind very often still in our modern world.
The social field still works after stone age principles.
A guru on tv yesterday said: "Bravery is to be very scared, but to use will power to overcome the fear and become a real man. It wouldn't be bravery if there was no fear."
Power needs helplessness in others, power through mind needs a deep fear in others to work.
If that fear is used to control a person, to make him very happy, the fear will also affect others in the same society.
The anger he needs to produce to control his own fear might spill over here and there, so we get some violence in the society for this system to work.
Male honor demands that you are always ready to fight physically.
Men need money, they need conviction. Power and well-being are based on conviction in the creationist system.
The women are trained to be very convincing, so they can convince a neurotic and violent man to believe in a good world, to become a nicer and kinder person as he gets older. That is how the current social system works.
But women are also trained to treat weak men, boys, badly. The women want strong men, men who are ready to defend themselves, men with strong minds.
Both men and women are trapped in a social system from the stone age, inherited generation for generation through personal contact, traditions, rules, ideologies.
Why do people use alcohol, tobacco, coffee, drugs medicines to feel good?
Because we are all forced to live at a high stress level, we have become used to a frenetic lifestyle. And the conviction and will power which was strong enough when we were young is not so strong anymore.
The reason are old religious traditions, based on the creation of marriages, the creation of the male mind, the holy spirit, the holy wrath, created love, the manipulation of people, the social power of the church.
We have been trying to abolish this old system and all its negative consequences for thousands of years, but the wise voices are few and the majority in the social field are still very occupied with administering and prolonging the stone age traditions, gender roles, fear and violence, strong convictions, stiff minds.
Yes, I as thinking along the same line. What about a separate unit that monitors the voltages, crowbars them in case of a fault, and removes the ac power to the computer?
As Speff points out, modern supplies are supposed to have the crowbars built in. However, Win 3.1 and Win 95 run fine on older computers, so they still have plenty of useful life. For example, I use Win 3.1 for internet access and have zero problems with trojans, viruses, popups, etc. They won't run on my system. Also have zero problem with upgrades breaking things. They don't exist:)
Thanks, Speff. The Teccor 40A scr looks very good.
Although the newer supplies may already have protection, many older computers still have plenty of use. For example, I log on the web with a 200MHz machine running Win 3.1, and have zero problems with viruses and trojans. They simply won't run. I use Win 95 on a 166MHz machine to view pdf files that need Acrobat 4, and my main computer is 450MHz running Linux. Each computer needs a backup, so I am looking at a triple boot machine running 166MHz. I also use several other cpu's for process control.
This gives a number of machines without protection, and I have already lost two due to power supply failure. So I'm thinking of a small ac-powered unit that crowbars the voltages and removes the AC to a faulty supply. A 40A scr probably won't even need a heat sink:)
The Intel failure section is hilarious. I copied it below for those who don't have the time to download it:
I wonder about a 'gentler' way. If you simply disconnect the main energy storage cap, then the supply won't stay pumping power into the output caps for more than a few microseconds.
I'm recently seeing more cheap PC supplies on the market which appear to be fake, in that the clammed output power not impossible for the size of parts inside. e.g I have a 500W "Shaw" brand ATX supply, and its output inductor uses a piddly T106 (26mm OD) core. The 5V is specified at
35Amps yet the output inductor winding is 2x1.2mm diam wire and the rectifiers for the 5V is a 15Ax2 Schottky device. This is typical for these very cheap power supplies. Similarly the 12V @ 18A output uses
2x8A diode (STPR1620).
I've also seen several other PC supplies that have completely omitted EMC components, and simply used wire links where the CM inductors are meant to go. Some PC supplies I've come across have even used standard ceramic/polyester capacitors in place of the Y and X2 rated safety capacitors.
They can, and they will, until these underrated and dangerous PSUs generate sufficient fires/casualties/deaths to trigger a judicial/coroners enquiry. A negative finding will cause ALL the companies who make the PSUs to disappear, and the importers/resellers to wave their certified performance/compliance paperwork as a shield against prosecution.
Hmmm, would you have brands in mind that are bad/good?
So, should we be buying those Antec Power Supplies (TruPower or soemhting the name is I think)? But they are so expensive!!! (well, 2-3 times cost of cheap Power Supply...)
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