If you do the sums, it cheaper for them to leave out the surge suppressor components altogether and just pay up on any such incident. Power line surges (in the UK at least) is a vanishingly insignificant source of damage.
Haven't had anything break that was plugged into it, although the power has flickered or quit many times during storms. But then, the TV and VCR are still working, and they're not on a surge protector.
A brownout is generally recognized as planned voltage cuts - or undervoltage. My utility in the US routinely implements 3% and 5% voltage cuts to shave or reduce peaks (and thereby save $' when buying power).
There is also the issue of spikes and harmonics.
Given a current laptop/desktop will be ~ $800USD to ~$4000 for a high performance system and a UPS sells for $40 - why subject a computer to unexpected power events? What is the value of the data on the hdd(s)?
This just isn't an issue in the UK, about which the original question was asked. Maybe it's more of a problem in the US for some reason?
No, there's no hardware nor data worth saving in the UK.
A 3 or 5% reduction in voltage, also known as a brownout to the utility, is totally irrelevant to electronics and especially irrelevant to computers. A computer works just fine even when incandescent bulbs dim to less than 40% intensity. Even demanded in Intel specifications. IOW what the utility calls a voltage reduction is full power to the computer. Utility would have to decrease voltage more than
20% for a computer to see a brownout. But if utility voltage drops that low, then electric motors may be damaged. IOW voltage too low to damage electric motors is even full power to a computer - which demonstrates how resilient a computer really is.BTW, utility does not institute a voltage reduction to save money. Voltage reductions are a last ditch effort to avoid rolling blackouts.
Spikes and harmonics are (or should be) irrelevant to a computer. Again, because the computer is so resilient. However that internal computer protection assumes the building has a 'whole house' protector so that spikes cannot overwhelm computer internal protection.
All of which is irrelevant to HD protection. Either the power supply will output correct power or it will shutdown. This, of course, assumes the computer assembler had basic electrical knowledge and did not install those 'defective by design' $25 or $40 power supplies. But again, this was explained earlier.
There is noth> A brownout is generally recognized as planned voltage cuts -
Or to avoid the expense of bringing additional generating capacity online, thereby saving money...
A PSU shutting down is not irrelevant to HD protection. Shutdown at the wrong moment (especially with the wrong operating system) and you end up with a badly trashed filesystem.
I have operated computers much further from 120V with absolutely no problems.
Once at the end of 100ft extension cord along with 1500W heater, lights dimming.
The other time at 130V, light bulbs popping every month.
Even on a generator nearly out of gas I had a minute to shutdown my system, no corruption occured.
True - my opinion as well - perhaps you could convince my local utility re this procedure being used on a daily basis.
Perhaps you could explain the half dozen UPS I have seen that operated correctly and interrupted close in electrical faults. Naturally the UPS were scrap after the electrical event - but the protected electronics were ok. $40 UPS vs $800 desktop or in one situation $200 - $300 UPS vs. $5000 of servers.
Was UPS between AC mains and computer? No. UPS and computer both connect to AC mains just like light bulbs. In fact it would be same protection if both computer and UPS shared same wall receptacle. Any transient from the receptacle confronts UPS and computer equally. However protection inside a UPS is often so grossly undersized that a surge too small to damage a computer might still damage the UPS. Furthermore, some computers can even act as surge protectors - shunt a destructive surge so that it does not seek earth ground via other computers.
Until you define specific circuits - including how every wall receptacle is wired, then I cannot provide more information.
I cannot say exactly why that particular event happened. But above is one reason why a UPS may be damaged and computer is not. Computer power supplies have internal protection. Protection so sufficient that there is little adjacent to a power supply that can enhance protection. But computer internal protection can be overwhelmed if destructive transients are not earthed before entering the building.
Bottom line is this. You had UPS failure. Therefore you have no effective surge protection. Even surge protectors must not be damaged due to a surge.
To provide a better answer, do as I do - autopsy the dead body. Replace the defective part to learn what has actually been damaged. Autopsy only complete when the failed unit is fully functional.
If a server farm has no 'whole house' protection and a single point earth ground, then no UPS or plug-in protector is going to do anything better. In fact, it is just not a reliable operation if 1) every incoming utility line does not enter at the common service entrance all connected to the single point earth ground and 2) building does not have necessary 'whole house' protector on incoming AC mains. From Sun Microsystems planning guide:
If you are suffering transient damage, then the human is reason for failure. What Sun writes is so well proven and understood that it was standard even before WWII. Protection is only as effective as its earth ground.
As for your brownouts - if any voltage is too low for a computer, then the utility has grossly violated nati>> A 3 or 5% reduction in voltage, also known as a brownout to
That's simply wrong/false. A good UPS or good surge protector WILL protect a PC. Do you understand the concept of common mode?
That's simply wrong/false. There is nothing magic about 10 feet except that an electrical pulse travels about that far in 10 nanoseconds. What do you suppose the risetime of a lightening bolt is and how does that relate to that 10 feet? Define "central earth ground" and what it's important characteristics are. Where is the "central earth ground" on an airplane, car, ISS or on the Antartic pole US base(over a mile thick cold pure ice)? Are all PCs and electronics gadgets there doomed? Ever heard on the concept of a Farady cage?
Yes, for those who actually understand it. What does the "central earth ground" look like at a major power station, substation or hydroelectric dam? Where's it located?
Again, the trashed filesystem is a problems of FAT and other simplistic file systems. It is not a problem to superior (journalizing) filesystems.
Will a disk drive write to the platter as voltage drops? Of course not. The disk drive controller is a complete computer that also monitors voltage. It does not matter to disk hardware when power is turned off. But it does matter to some 'simplistic' disk filesystems that power is not removed during a write operation.
Just another reas> w_tom wrote:
Ok sir. Explain to us how a plug-in UPS provides common mode protection. Also cite the manufactuer's spec that claims that common mode protection (and good luck).
Also please explain how those 130 ohms impedance in 50' of
12 AWG wire is not significant when earthing even a trivial 100 amp surge?In the meantime, please explain how earth ground at a hydro electric plant is at all related to single point earth ground for a building, for a PA or stereo system, for the PC board layout of A/D converters, or any other simple electronic system where ground loops can be a problem. You do understand the concept of ground loop? Good. Please then show us how the ground at a power station has any relevance?
Now for the completely irrelevant topic of ground in an airplane:
R>> There is nothing cost effective adjacent to the computer. No
No problem. Here:
Do you understand what common mode means with respect to the above spec and do you understand how that differs/same as the general concept of common mode and how that relates to these issues?
In order to protect a device from an undesirable voltage arriving over the power cable one simply shunts that unwanted voltage such that it appears equally on all the wires on that power cable i.e. AC-hot, AC-neutral and the ground wire which connects to the chassis of the device. That shunt is done with capacitors and surge diodes or MOV devices etc. or in the old days on your phone line with a spark gap. That's basically what a surge suppressor does. The device's input components therefore see no intolerable VOLTAGES and it survives. It makes no difference to the device if the whole device(chassis and all) jumps to a million volts during the episode. Ever heard of a Faraday Cage?
Not relevant. What happens on an airplane? The protection issue isn't grounding a surge current; the issue is maintaining important components at a stable/safe voltage with respect to one another such that nothing gets damaged. Ever heard of a Faraday Cage?
In large buildings as in hydroelectric plants there is NO SINGLE POINT ground but multiple connections to a common ground cage/plane. On an airplane there isn't even one point to ground except an ionized air column t hat chooses its own path for a few microseconds at a time on occasion. Ever heard of the concept of a ground plane? Every heard on the concept of capacitive coupling and AC impedance? How does a Faraday Cage relate to a ground plane?
You're walkin into my backyard now. Now what's the difference in design of that DA for 8 bit 800MHz conversion and 24 bit 200KHz conversion? DAs are more fun that ADs.
It's entirely relevant to demonstrating that you have no understanding of the issues in question.
The answer is that the principles of how to do system input protection on an airplane are IDENTICAL to how to do them at home or in a high rise.
The NUMBER ONE FAILURE of an incompetent designer in this arena is to mistake that a ground connection has much to do with the issue; it does NOT. The ground connection has much more to do with other issues like the safety of the guy who is using the box and the UL and the national electrical code. Why do you suppose that US home wiring didn't even include a 3rd wire(ground) until the 50's? Do you think some new physical law was suddenly discovered?
One can protect a gadget from surges WITHOUT a ground wire or any ground at all; that's the WHOLE point. Shunt the surge voltage such that it's common moded and to the chassis at the input and outputs and the device is protected.
OH, cool but of course it simply proves my points.
You mean beyond you.
No, airplanes are impossible to proactively ground while in flight(save a high energy beam) and much more importantly the is no need to ground an airplane in flight. There is just a need to have a good continuous Faraday Cage. Damn, how did anyone ever survive when planes were made of wood or paper(or are they non-conductors)?
Oh, you mean the Faraday Cage was discontinuous or flawed or maybe it was a super bolt of the kind that has punched holes in heavy gauge steel petroleum tanks. In any case I'll bet that the cockpit radio was undamaged at least until impact.
HUH?
Because device/PC protection design has little to do with earth grounding.
Wrong. Topologically the UPS is "between".
WRONG! About a critical 10 nanoseconds WRONG nevermind the impedances and common mode condiderations!
Not in the critical time domain.
NO, the first component with surge suppression topologically is usually the one that takes the HIT. Do you suppose that's by design?
OH, you mean unless the building is a heavily constructed Faraday cage and all wiring has feedthru bypass and surge suppression, then a destructive transient could get through and that has NOTHING to do with you high transient impedance ground wire.. Why is it that we all knew that?
HUH, frequently good surge protectors are destroyed by big surges just as they are designed to do. The good one FAIL closed circuit where protection is even better!
NO, a large server farm has grid ground and power grid firewalls.
No, you are getting closer to reality.
To a good Faraday cage or ground plane. A circuit of LOW AC IMPEDANCE.
What that all boils down to is design the Faraday Cage or ground plane well and has little to do with actual earth grounding save the UL and electrical code.
Happened here. Power surge, while I was working on a MS-Word document.
Returned, Windows booted, but crashed at the desktop, so I entered using a Win98 boot disk and ran Scandisk.
2 or 3 bad blocks, and some files/Windows' registry were corrupted. []sPlease feel free to show us an MOV datasheet that says
That claim is classic urban myth. MOV data sheets define normal operation. MOV is at end of life typically when it degrades by about 5%. How can it degrade 5% and yet vaporize? It cannot. Bottom line remains - a properly sized protector shunts the transient and remains fully operational. Eventually MOV degrades; does not vaporize. Vaporizing is when the MOV grossly exceeds manufacturer specification - is grossly undersized for the task. But purveyors of undersized and ineffective protectors want consumers to believe their overpriced protector should vaporize on every surge. Scam is the better word.
Well lets see. The Boeing 707 was an entire 'faraday cage' of aluminum. And inside that aluminum 'faraday cage' was a completely enclosed fuel tank - another faraday cage. How did lightning get through two faraday cages to explode the fuel tank on that Boeing 707? And why was the correction to install more grounds inside that 'faraday cage'? Could it be that no sufficient 'faraday cage' exists? Yep.
R>> Transmitted an incomplete post. Sorry for the mistake.
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