# Surge Protector



## tammy20 (Oct 28, 2007)

Hi, Do I need a surge protector for my new laptop? If so, are the mini 2 outlet ones enough. I really do not know which one to get. I googled it but most of them said you did not need one. Thank you for your help.


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## daniel_b2380 (Jan 31, 2003)

tammy,
couple things come in to play here,
as i asked in your 'configuration' thread,
will you be traveling much with this unit?
for the price of surge protectors today,
a definite yes,
but DON'T buy an 'el-cheapo'
get a decent one,
or just don't bother using one at all,
[false sense of security],
.
for at home use,
i would do a step up to a ups unit,
AND, i like apc brand,
quality units + good support = satisfied customer, 
.
this part may be 'gobbly-****-tech-speak' to you,
but it is important,
with cost-cutting what it is today,
some manufactures use the battery to help filter the power,
some do a better job and add the necessary components,
the more stable the power supply,
the more stable windows will run,


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## tammy20 (Oct 28, 2007)

Hi, I will just be taking it around in the house and when I go to friends houses.


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## daniel_b2380 (Jan 31, 2003)

ok,
and you read the REST of the post?


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## tammy20 (Oct 28, 2007)

Sorry about that...thank you so much for your help today.


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## DoubleHelix (Dec 10, 2004)

You can get a small, portable surge protector to travel with. I would definitely recommend it.


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## w_tom (Nov 29, 2008)

Laptops already contain internal protection and other features. For example, your 120 volt laptop will even work fine when AC voltages peak repeatedly at 370 volts. To a laptop, that is considered normal voltage.

 Meanwhile, what will that portable protector do? If got recommended without a single statement that says what it does. Many just saw the word surge protector and assumed it protects from all types of surges. Not until you have read the manufacturer's numeric spec sheets. Where does it list each type of surge and protection from that surge? Little hint. It only protects from a type of surge that is made relevant by the laptops internal protection.

 Did you really think that silly little $3 box with some $0.10 parts inside was going to stop and absorb what three miles of sky could not? That is what others have claimed. Do you really think that few hundred joules will absorb surges that are tens and hundreds of thousands of joules?

 See those costs? A $3 box with some $0.10 parts. How much does it sell for? $25? Monster sells for up to $150 for the same protector circuit also sold for $10 in the grocery store. What is it protecting? Your computer or a profit margin?

 Just a few damning questions that are asked by those who cannot recommend a protector without also stating why and how it works.

 All electronics need protection so that the rare surge does not overwhelm protection already inside the laptop. However, protection from that type of surge must be installed where the surge enters a building. That protector works even better when the distance between laptop and protector is increased.

 Laptop circuits are even rated to withstand 2000+ volts without damage. Protection for laptops means the rare (maybe once every seven year) surge does not even enter the building. Notice the missing manufacturer spec numbers - that do not even claim to provide that protection. Did they really think that few hundred joules box would stop and absorb a hundred thousand joules? What three miles of sky could not? If it does not do that, then what is it protecting from? Notice that nobody said. Notice even the manufacturer spec does not claim that protection.

If it provided protection, the recommendation also said why and from what - with numbers.


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## daniel_b2380 (Jan 31, 2003)

w_tom Junior Member with 1 posts
About w_tom 
Experience
Advanced



> For example, your 120 volt laptop will even work fine when AC voltages peak repeatedly at 370 volts. To a laptop, that is considered normal voltage.





> Laptop circuits are even rated to withstand 2000+ volts without damage.


right, i know, you know alllll about it,
i know, they just don't understand what you're trying to tell them,
especially when you talk all that technical stuff,
yeah, they're just jealous 'cause they don't understand it like you do,
you sure understand 'bout all them jewels,
and them voltage peaks, and surgings,
yeah, you got it,
.
here, take these little 'candies'
why yes, we do call them valiums,
they'll help you feel better though,
come on now help me here,
we need to get you back into your little jacket,
that's it, just put your arm in here,
oh yes, we'll sure 'nuff roll the cuffs up and fix them just for you,
.
ok, is the ranting temper tantrum over now?
are we feeling better now?


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## K7M (Feb 27, 2000)

I wonder about the validity of what w_tom has said. My laptop adapter is rated for 100 to 240 volts. Now that is quite a range of voltage for a power supply. 
Years ago my friends well got hit by lightning. the power followed the wire for the pump into the house to the service panel, and through the ground wire back to earth. It blew his pump, caught the service panel on fire and blew out all the surge protectors and power supplies in all of his computers. Now this is rather a large hit but why did it not blow his tv's and microwave. All that was gone in those appliances was the fuse, replaced the fuses and all was well. Lightning takes the shortest path to ground, hence the circuits in the surge protectors, close to the computers. I really think in most cases they give a false sense of security. I don't use one on my laptop, and on my desktops I have a UPS on 2 of the 4 in the house. lost 2 power supplies on 2 of the 4 during a storm. One had protection the other didn't. go figure.


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## w_tom (Nov 29, 2008)

K7M said:


> Lightning takes the shortest path to ground, hence the circuits in the surge protectors, close to the computers. I really think in most cases they give a false sense of security. I don't use one on my laptop, and on my desktops I have a UPS on 2 of the 4 in the house. lost 2 power supplies on 2 of the 4 during a storm. One had protection the other didn't. go figure.


 Noted was the important point. What was the best path to earth?

How does a surge protector stop and absorb surges? Surge that obtains earth ground before entering a building need not find destructive paths through appliances. An effective protector does not absorb surges. It makes a short (ie. 'less than 10 foot') temporary connection to earth. Protection increases when the protector is distant from electronics (telcos prefer their protectors up to 50 meters from switching computers).

If a surge is not properly earthed, then it may build an undesirable plasma path. That short circuit means high energy - utility AC power - now conducts causing massive damage (ie the breaker box).

Why does that plug-in protector (or UPS) not claim protection in manufacturer numeric specs? Where is its short connection to earth? If it cannot harmlessly earth surges, then where does surge energy get dissipated?

Again, view joules numbers for both power strips or the UPS. Just enough above zero to claim some protection. Close enough to zero to maximize profits and still get promoted by those who ignore spec numbers.

A laptop rated for 100 to 240 volts RMS is for 90 to 265 VAC. Normal operation voltages can peak at 370 volts. Internal protection found in laptops and all other computers is significantly higher. Protection means a larger and rare (maybe once every seven years) surge is earthed before entering a building. Does not overwhelm protection already inside a laptop. Such protectors, sold by companies with responsible reputations (ie Leviton, Square D, General Electric, Siemens, Intermatic, Keison, Cutler-Hammer (Eaton), etc), earth direct lightning strikes without failure. 

Surge protection means people never even knew a surge existed. For example, a Cutler-Hammer protector selling in Lowes for less than $50 is rated to earth direct lightning strikes without failure. Breaker box earthing also must meet and exceed post 1990 National Electrical Code requirements. A 'whole house' protector and earthing means direct lightning strikes need not enter a building. Protection inside a laptop is not overwhelmed.

Essential to surge protection is a short path to earth. Earthing to the same ground used by the telco (installed for free) protector and a direct connection to TV cable. Protection means any wire inside every cable is somehow connected to earth where that wire enters the building. Some wires (ie coax cable) need no protector - are earthed directly. Other wires (ie telephone, AC electric) cannot be earthed directly. So we make that connection with a surge protector. Effective protectors connect surges short to earth - do not stop and absorb surges. 

What does a protector without any short, dedicated earthing do? Again, read what each protector claims to protect from in numeric specs. Notice a shortage of protection numbers and woefully too few joules. Just enough joules to claim "surge protector" on its color glossy sales brochure. Does it provide protection or just sell a half truth on sales brochures? See responsible companies for one 'whole house' protector. Appreciate why your telco installs an earthed protector for free. Appreciate why cable companies recommend no protectors on their cable because cable is earthed where it enters the building. Appreciate what provides protection. Surge energy gets dissipated harmlessly in earth.


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## JohnWill (Oct 19, 2002)

Obviously, surge protectors close to equipment are not designed to take a direct lightning hit! They also won't deal with something like a floating neutral line, something that happens more than you might imagine.

I've see a whole hose surge protector with the cover blown completely off the box, it happened to be a Leviton model. This was the result of a downed pole, obviously a serious overvoltage made it into the panel. That same surge took out pretty much all the "smart" dimmers in his house, as well as a computer, a couple of TV's, and assorted small electronic appliances.

I believe that any surge protector that's properly grounded with a good return is better than nothing, but it's not a bionic shield. FWIW, I've taken my laptops on the road many times over the years with no surge protector in all sorts of environments from hotels, conference rooms, and even running off stand-alone generators. I've never experienced any failures due to surges. I'd also note that the power brick is far more likely to be the victim of a surge, the chance for it to get past that into the DC is much less likely.

My preference for equipment protection is a UPS, since that has decent surge protection and also removes the equipment from the line in an overvoltage situation.


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## w_tom (Nov 29, 2008)

JohnWill said:


> My preference for equipment protection is a UPS, since that has decent surge protection and also removes the equipment from the line in an overvoltage situation.


Nothing claims to be a bionic shield. If that UPS provides protection, well, the same galvanic isolation, required in computer's power supplies, is the same protection.

 That assumes a $500 UPS. A conventional computer grade UPS (that most have) connects a computer directly to AC mains when not in battery backup mode. That galvanic isolation does not even exist. Meanwhile, the safety ground wire is how surges can completely bypass the UPS. So where is this protection?

 'Dirtiest' power occurs when a UPS is in battery backup mode. When its relay disconnects from AC mains; when only a battery powers the computer. How does that relay make better protection? It does not for a long list of reasons. For example, view those manufacturer specs. The relay takes milliseconds to respond. Surges are microsecond events.

 On an oscilloscope, a typically 120 VAC UPS outputs two 200 volt square waves with a spike of up to 270 volts between those square waves. Is this UPS output 'cleaner'? Of course not. This 'dirtiest' UPS power is why UPS manufacturers quietly recommend not connecting power strip protectors or small electric motors to its output. But since protection inside a PC is so robust, then a UPS 200 volt square wave with 270 volt spike is not harmful.

 So where is that UPS protection? If that UPS is decent protection, it would say so in numeric specs. View those numbers. Joules for a UPS is less than most power strip protectors. A UPS only has the same protection circuit found in power strips - but smaller - fewer joules.

 An IEEE standard entitled 'Static and Lightning Protection Grounding' says earthed 'whole house' protection is not a bionic shield:
> Lightning cannot be prevented; it can only be intercepted or 
> diverted to a path which will, if well designed and constructed, 
> not result in damage. Even this means is not positive, 
> providing only 99.5-99.9% protection. ...
> Still, a 99.5% protection level will reduce the incidence of direct 
> strokes from one stroke per 30 years ... to one stroke per 
> 6000 years ...


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## JohnWill (Oct 19, 2002)

All typically true, but a microsecond surge is very unlikely to do as much damage as an extended over voltage condition. I've seen the results of over-voltage in three cases in the last few years, two of them resulted in significant damage to many of the devices on-line at the time. When I had a floating neutral here, I saw one side of the line at 70 volts, and the other side at 175 volts. The UPS systems were screaming away and had isolated all the computer equipment, nothing was damaged in any way. I lost a couple of clock radios that happened to be on the high side, and several dimmers.

I'll keep my UPS systems, thanks. Since you believe a UPS has no beneficial effect, I suggest you not use one. 

The switching power supplies on your computer don't really care if it's square waves or sine waves, since they are just charging capacitors on the primary side of the supply. The RMS value of the output is what's important here, that's the primary goal. Is a square wave ideal? Probably not, but it's also not a major issue and certainly beats a sustained over-voltage situation which is the most damaging scenario.



Also, I really doubt that any of the typical whole house surge protectors offer anything like 99% protection, especially from a direct strike on the lines close to the house. Quite simply, there is no practical protection from that scenario. Now, it's not that common for a strike to hit on your side of the transformer in most cases, so you have pretty good isolation from the full force of the strike. I've seen the effects of a direct lightning strike, it's not a pretty sight.


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## Drabdr (Nov 26, 2007)

Hello, Tammy!

It's actually a good question. For 120V power supplys, I am a firm believer in surge suppressors for equipment. Essentially, what you are trying to protect is Mega over voltage conditions that may find its way into your equipment. As you well know, electricity seeks the path of least resistance. The suppressor (as John mentioned, with an effective ground) will "flow" any excess voltage to ground, and not to your equipment.

I have a small surge suppressor I always keep for my laptop. Actually, I have all my electronic equipment on surge suppressors.

There are surge suppressors that you can have installed on your main panel on your house. Depending on where you live, that would range from $600-1000 dollars. While that sounds like a large amount of money, consider your home deductible cost, should lighting or such hit your electrical system at your home. Remember... you're talking clocks, radios, stereo, TV, computers,.... Just something to consider.

Sorry I got way off track. Anyway... yes, I always have surge suppressors for 120V electronic products.


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## Cookiegal (Aug 27, 2003)

daniel_b2380 said:


> w_tom Junior Member with 1 posts
> About w_tom
> Experience
> Advanced
> ...


Whether or not someone is right, and I don't know who is right here, it doesn't justify such a sarcastic response to another member. Please be more careful in the future.


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## JohnWill (Oct 19, 2002)

Note that many insurance policies will actually cover the damage caused by a power surge. I was somewhat surprised that the one instance I mentioned where there was major damage was covered almost completely. It might be worth checking your insurance policy terms.


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## w_tom (Nov 29, 2008)

JohnWill said:


> All typically true, but a microsecond surge is very unlikely to do as much damage as an extended over voltage condition. ... The switching power supplies on your computer don't really care if it's square waves or sine waves, since they are just charging capacitors on the primary side of the supply.


 A microseconds surge is the most common source of damage. Therefore surge protection specifications list numbers for the most typically 8 by 20 microsecond surge. Recommended is the only type of surge protector installed where damage must never result - ie. every telco CO, US Air Force facilities, nuclear hardened radio stations, etc.

 Your overvoltage goes right through the typical UPS. Most UPSes do not claim to protect from a sustained 170 volts on 120 VAC - ie open neutral. But then open neutral is also why the building earth ground is so essential - to minimize that problem. Many older homes especially are venerable do to an insufficient or missing earth ground. A 'magic box' UPS to only protect one item often does not even provide that protection. Fix the ground to protect everything. 

 Surge protectors (even in UPSes) typically ignore voltages below 330 volts. Find the 'let-through voltage' number often listed on its cardboard box. Just another reason why a UPS is not for open neutral problems. However some electronics are so robust as to make 170 volts irrelevant.

 Why does your telco use 'whole house' protectors and never use plug-in protectors in every CO (Central Office)? A typical thunderstorm causes maybe 100 surges and must never once damage any switching computer in any telco CO. Yes, the 'whole house' protectors are that effective and were standard even 100 years ago.

 Recently, a 33,000 volt wire dropped onto the local distribution. Hundreds of electric meters were literally blown from their pans. Exploding out 30+ feet from buildings. Many who had plug-in protectors, of course, suffered damage. But my friend had no plug-in protector and only one 'whole house' protector. He had no damage (except that his meter was also blown off the building). 'Whole house' protectors are that effective which is why the responsible companies sell them and why companies such as APC do not. 'Whole house' protectors are so effective as to be part of the protection even in munitions dumps.

 Your UPS is for battery backup - to protect from data loss. Electronics are so robust as to make a UPS's square waves and spikes irrelevant (as you noted). Electronics are that robust which is why we install surge protection so that a rare and destructive surge (a lightning striking to a transformer) does not cause any household appliance failure. Instead we protect everything. Even the dishwasher and furnace need that protection. What appliance is most essential during a surge and can only be protected by a 'whole house' protector? Smoke detectors. That superior solution is installed for for tens or 100 times less money.

 What is that - 12 different reasons to install a 'whole house' protector and fix the earthing? That UPS does not even claim to solve any of them. That and not a UPS is Tammy's better solution.


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## daniel_b2380 (Jan 31, 2003)

cookiegal,
going to try to answer something here,
maybe a specific question that was not asked by you,
but was inferred by your statement directed toward me,
in that it was my post that was 'quoted-in-part'

post #1


> Surge Protector
> Hi, Do I need a surge protector for my new laptop? If so, are the mini 2 outlet ones enough. I really do not know which one to get. I googled it but most of them said you did not need one. Thank you for your help.


post #2


> tammy,
> couple things come in to play here,
> as i asked in your 'configuration' thread,
> will you be traveling much with this unit?
> ...


the above answer i gave i tried to base upon the 'apparent' insinuated level of the op's level of expertise and understanding by the words used by the op in the question in the way that it was asked,
NOT inundate her with hyperbole and misplaced trivial ramblings about a subject, physics, which i spent a whole lot of $$$$ and time, at cal poly learning about to get my degree,
contrary to the next post:

post #7


> Laptops already contain internal protection and other features. For example, *your 120 volt laptop will even work fine when AC voltages peak repeatedly at 370 volts.* To a laptop, that is considered normal voltage.
> 
> *Meanwhile, what will that portable protector do? *If got recommended without a single statement that says what it does. Many just saw the word surge protector and assumed it protects from all types of surges. Not until you have read the manufacturer's numeric spec sheets. Where does it list each type of surge and protection from that surge? Little hint. It only protects from a type of surge that is made relevant by the laptops internal protection.
> 
> ...


[gee, was there any sarcasism in the above post i wonder if one actually reads what is there?],

23-Mar-2009, 03:21 PM #8


> > For example, your 120 volt laptop will even work fine when AC voltages peak repeatedly at 370 volts. To a laptop, that is considered normal voltage.
> 
> 
> 
> ...


was this post truly sarcastic especially if one reads the entirity of the post?
and not just my two quotes from it?
.
i did notice when you quoted my post,
i was only 'quoted-in-part'
you left out even the two questions i did ask,
which likely made the post sound much more sarcastic than if they had been included,
or especially the previous post in IT'S entirety,
.
i quoted just TWO items,
which, without a further explanation,
become to a layperson, TOTALLY egregious errors,
when no further explanation of the hyperbole is produced,
were they ever answered?
or, did the rant continue?

especially when op had asked:

post #1


> Surge Protector
> Hi, Do I need a surge protector for my new laptop? If so, are the mini 2 outlet ones enough. I really do not know which one to get. I googled it but most of them said you did not need one. Thank you for your help.


and in my post #2, i had said:


> this part may be 'gobbly-****-tech-speak' to you,
> but it is important,
> with cost-cutting what it is today,
> some manufactures use the battery to help filter the power,
> ...


really still words that anyone capable of reading a newspaper today could understand,
.
but it continued on:

post #10


> Noted was the important point. What was the best path to earth?
> 
> How does a surge protector stop and absorb surges? Surge that obtains earth ground before entering a building need not find destructive paths through appliances. An effective protector does not absorb surges. It makes a short (ie. 'less than 10 foot') temporary connection to earth. Protection increases when the protector is distant from electronics (telcos prefer their protectors up to 50 meters from switching computers).
> 
> ...


and still continued on:
post #12


> Nothing claims to be a bionic shield. If that UPS provides protection, well, the same galvanic isolation, required in computer's power supplies, is the same protection.
> 
> That assumes a $500 UPS. A conventional computer grade UPS (that most have) connects a computer directly to AC mains when not in battery backup mode. That galvanic isolation does not even exist. Meanwhile, the safety ground wire is how surges can completely bypass the UPS. So where is this protection?
> 
> ...


so read the above,
then consider again WHAT the op was actually asking,
AND the context in which it WAS asked in post #1,

post #1


> Surge Protector
> Hi, Do I need a surge protector for my new laptop? If so, are the mini 2 outlet ones enough. I really do not know which one to get. I googled it but most of them said you did not need one. Thank you for your help.


and the answer i gave in post #2,
then the reply in post #7,
i don't know,
maybe others weren't able to read it very well because of the english and grammar usage,
maybe my degree in english lit helps,
maybe i have an 'edge' over many,
in that because of the business dealings,
i have traveled over a great deal of this globe we call earth,

in all actuality,
if a thread had been started in, say, random discussion,
and a post made in this thread,
posting a link to their 'reasonings'
to the effect that someone wanted to disagree with me,
.
which would not have, at this point, more than likely,
left the op wondering 'WHAT are they jabbering about?'
.
in turn, derailing and hijacking the original poster's question
that the thread was originally started for,
in effect, relagating it to 'nothingness'



> Whether or not someone is right, and I don't know who is right here, it doesn't justify such a sarcastic response to another member. Please be more careful in the future.


therefore, no,
i do not choose to accept full responsibility for what has transpired,
to have caused me to post what i did,
.
thank you,
daniel


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## w_tom (Nov 29, 2008)

Drabdr said:


> ... I am a firm believer in surge suppressors for equipment. Essentially, what you are trying to protect is Mega over voltage conditions that may find its way into your equipment.


 Tammy - I am also a firm believer in a surge suppressor - that actually do provide surge protection. And I am an electrical engineer who even designed some stuff for locations that could never suffer damage. Do you think that silly little 'less than one inch' component inside a portable protector will stop megavolts? Of course not. It does not even claim to. 

Surge protection is not about path of least resistance. It is about path of lowest impedance. But again, that is the difference between laymen and engineers. There is no earth ground in the plug-in protector. Impedance is why an effective protector (ie telco COs) are installed distant from the electronics and as close to earth ground as is possible. Provided was a critical number: 'less than 10 feet'. To be effective, the protector connection must be that short.

A sufficiently sized 'whole house' protector (from Cutler-Hammer - one of the more responsible companies) even sells in Lowes for $50. Not $600. That $50 unit is sized to earth direct lightning strikes without failure (ie 50,000 amps - but again, I provided numbers. Don't take my word for it. View those numbers yourself on the Lowe's store shelf).

Laptops already contain better protection. However a plug-in protector may even contribute to laptop damage (depending on how the building is wired and type of surge). Some actually claim it will absorb what three miles of sky could not stop!

Meanwhile, if a UPS is protection, well, what is also inside a laptop? A battery connected to a UPS. Just another reason why that portable protector does nothing useful for a laptop.

Those portable protectors do not claim to protect from typically destructive surges. But should you feel it necessary, the same protector circuit is inside a grocery store protector sells for about $7.


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## w_tom (Nov 29, 2008)

daniel_b2380 said:


> [gee, was there any sarcasism in the above post i wonder if one actually reads what is there?


I do not know about sarcasm. But I do know facts and numbers. A protector selling for $7 in the grocery store is the protector circuit selling under a Monster Cable label for $150. Little relationship exists between price and protector quality because protectors are so often recommended on myths - not on facts and numbers.

 Noted but again is that any protection afforded by that portable protector is already inside the laptop. Then listed are the many reasons why we know laptops are so robust. They can withstand routine voltage spikes even output by a UPS. Can work even when AC main voltages peak constantly at 370 volts. Laptop supplies are rated to withstand as much as 2000 volts. If a UPS is protection, well, the laptop already contains a UPS internally.

 But if Tammy still needs a protector, the $7 protector in a grocery store has the same protector circuit as other protectors selling for significantly more money.

 The UPS was identified as trivial if any protection. A 'whole house' protector is essential for everything in a house - including the laptop. A laptop portable protector is wasted money and more traveling weight. No sarcasm. No oversized letters. Just straight (and unpopular) technical facts - with numbers.


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## daniel_b2380 (Jan 31, 2003)

discuss = to consider or examine
argue = when one of the minds becomes closed to a different idea
.
since you persist in seeming to want to argue,
i choose NOT to WASTE any further of my time,

post #18


> a subject, physics, which i spent a whole lot of $$$$ and time, at cal poly learning about to get my degree,


post #13,


> I'll keep my UPS systems, thanks. Since you believe a UPS has no beneficial effect, I suggest you not use one.


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## Cookiegal (Aug 27, 2003)

daniel_b2380 said:


> therefore, no,
> i do not choose to accept full responsibility for what has transpired,
> to have caused me to post what i did,
> .
> ...


It was a warning, not an essay question. There is no excuse for being rude to another member. You may want to take a minute and read the rules. 

Also, it would help to make your posts easier to read, and require less scrolling, if you would type in regular sentences without putting unnecessary returns in the text so everything is scrunched over to the left side.


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## valis (Sep 24, 2004)

w_tom said:


> I do not know about sarcasm. But I do know facts and numbers. A protector selling for $7 in the grocery store is the protector circuit selling under a Monster Cable label for $150. Little relationship exists between price and protector quality because protectors are so often recommended on myths - not on facts and numbers.
> 
> Noted but again is that any protection afforded by that portable protector is already inside the laptop. Then listed are the many reasons why we know laptops are so robust. They can withstand routine voltage spikes even output by a UPS. Can work even when AC main voltages peak constantly at 370 volts. Laptop supplies are rated to withstand as much as 2000 volts. If a UPS is protection, well, the laptop already contains a UPS internally.
> 
> ...


actually the ones that cost more do tend to do more.

The ones I like best are the ones that are guaranteed against a lightening strike. Truth told, if the electricity of even a small lightning bolt were to go through one of those 'guaranteed' surge protectors all you'd have left is a puddle of plastic and metal. Last I checked, lightning bolts got pretty hot, somewhere around surface of the sun hot. Some people will say four times hotter, some will say ten times hotter, to me hot is hot. And that's all there is to it.

What they are betting on is whether or not your house will get _hit_ by a lightning bolt. If you do, well, then they'll shell out the 50k guarantee like it says on their box.

As for the differences between a wal-mart special for 5 bucks and something I use, which costs around 60 bucks, most of it back up power and line conditioning. Most pc's will have something built in to compensate for dirty juice coming of a line, but unless you are running a laptop, which I am not, they will not have anything to compensate for no juice. So for 60 bucks I got a really good surge protector and a really crappy ups (uninterruptible power supply). It buys me about a minute, max, to save whatever it is I'm working on. Which does come in handy, as we do get big boomers down here, and even though the thunder is miles away, all of a sudden *blink* no juice.

So yeah, if I was working on a column for a magazine or something and had been so focused I hadn't hit ctrl-s in the last half-hour, I got a few seconds to do that.

Works for me. Has for a decade or so. Of course, when a big boomer goes right over the top of us, I just unplug everything.

Because there isn't a damn thing, last I checked, that can stop a bolt of lightning.


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## tammy20 (Oct 28, 2007)

Thank yall for all the advice. I have been looking at UPS, but do not know how much I need for a laptop.


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## valis (Sep 24, 2004)

for a laptop a ups is not necessary. A laptop *is* a ups.  Just keep them charged up, and you'll do fine. When you are running on house current, just put something between your laptop and the house; such as a surge protector. I, personally, would recommend getting something in the 30 dollar range, as I think that's where the conditioning starts to come into play, but I could be wrong on that. JohnWill would know. He likes electricity. I do not. I find it to be, while extremely useful, also a bit dangerous and a touch on the shady side. Likes to bite you when you aren't looking.

But no, there is no need to go overboard and buy some super duper $400 surge protector that protects against lightning because one of those does not exist. JohnWill will back me up on that one.

Heck, I'm still trying to figure out what he meant by 'floating neutral line'. Sounds to me like something I'd expect to see on a fishing boat.

but then, I don't fish that much either.


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## Drabdr (Nov 26, 2007)

valis said:


> for a laptop a ups is not necessary. A laptop *is* a ups.  Just keep them charged up, and you'll do fine. When you are running on house current, just put something between your laptop and the house; such as a surge protector. I, personally, would recommend getting something in the 30 dollar range, as I think that's where the conditioning starts to come into play, but I could be wrong on that.


In general, yes you are correct. Just go to Home Depot, and get something for your computer (and possibly the phone line too) that protects against surges. It's not that difficult or expensive to protect an individual device.



valis said:


> But no, there is no need to go overboard and buy some super duper $400 surge protector that protects against lightning because one of those does not exist.


They don't protect against lightning; but will minimize damage due to a power surge from lightning.

Basically you're trying to protect yourself against lightning hitting a power line, phone line, or find entry into your home some other means. That electricity wants to go to earth ground, and will travel the path of least resistance. Without surge protection, that electricity will travel along the electrical conductors. For things like simple lamps, it may just burn out a bulb. For electronic equipment, it will overload the circuitry. That's $$$$ out of your pocket, your deductible, whatever.

A licensed electrician can install, at the main panel, a surge suppressor for the main power. Typically that involves driving a ground rod outside the home, and connecting the ground to the surge suppressor for the system. Then when the surge goes through the main panel, the surge suppressor is a lesser path than the house electrical grid. Thus, the main panel surge suppressor will absorb most of that power; thereby minimizing damage through the home.

The surge suppressors for the main panel are not that much. But when you get a decent 240 volt suppressor, have an electrician install and drive a ground rod, you're upwards of $600-1000.

Again, this is one option of many for folks, and like everything else, has risk/return.


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## JohnWill (Oct 19, 2002)

In the US, most residential power is 230V with a neutral center tap from the transformer. This is how 115V is obtained, connections between the neutral center tap and one of the hot legs from the transformer. If that neutral line is broken, a _floating neutral_ is the result. Now, any 115V device has to have it's common return through other devices on the opposite side of the transformer. If the loads aren't balanced (they rarely are), the result will be that one side of the 115V feed has a much higher voltage than the other side. It's the same as connecting two resistors in series to a power supply. If the resistances are unequal, one side will have a greater voltage drop.

230V devices switching on and off will also change the voltage balance, it's interesting to watch.


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## w_tom (Nov 29, 2008)

valis said:


> actually the ones that cost more do tend to do more.


 If it costs more, then you have numbers to show that "better". No number and no manufacturer specs are provided because numbers say otherwise. That $60 protector is same as the $7 protector.

Its warranty is so full of exemptions as to not be honored. For example, one APC product defined using protector anywhere in the building from another manufacturer voided their warranty. That warranty comes with at least 10 reasons to not be honored. Obvious by reading the fine print. Warranty on a $60 protector is, for all practical purposes, same as the warranty on the $7 protector. Same protection circuit. Same protector but with a $50 higher profit margin.

Laptop already contains a UPS. Any protection provided by a separate UPS is already inside the laptop. The laptop remains at risk (with or without the UPS) if a 'whole house' protector is not installed. Only solution to a safer laptop is earthing one 'whole house' protector. Same reason why telcos all over the world use the 'whole house' solution and do not waste money on plug-in solutions.

Floating neutral causes half a house to see low voltage while the other half sees a high voltage. Basic electrical knowledge means a floating neutral is easily understood. Same knowledge is also necessary to recommend surge protectors. How do some make recommendations and not know about floating neutrals?

No protector protects from a floating neutral. Essential is a short term solution: a required earth ground. Floating neutral is identified by incandescent lamps that glow brighter or dim when a major appliance powers on. John Wills implied his always required earthing was missing AND he did not understand this basic electrical concepts. Instead of fixing the earthing, he would recommend surge protection? Yes, most plug-in protectors recommendation come from those who don't understand basic electrical concepts- but heard the popular urban myths.

No surge recommendation protects from floating neutrals. Numbers make that obvious. Surge protection is about making lightning irrelevant.

A sufficiently sized 'whole house' protector from Cutler-Hammer is sold in Lowes for less than $50. Some $10 earth ground rods may be installed to meet post 1990 National Electrical Code requirements. Homes constructed after 1990 should not need those $10 ground rods. Some spend $600 for these same parts. Anyone having any electrical work done would be irresponsible not having that electrician also upgrade earthing (essential) and install one 'whole house' protector. After all, most of that $600 is the cost of him getting there. The work and parts are cheap. Easily installed by anyone who can install a circuit breaker. Essential for any effective surge protection.

This engineer did not make recommendations quoting urban myths. Numbers from an IEEE Standard were quoted. We properly earth one $50 'whole house' protector for protection this effective:
> Even this means is not positive, providing only 99.5-99.9%
> protection. ...
> Still, a 99.5% protection level will reduce the incidence of direct 
> strokes from one stroke per 30 years ... to one stroke per 
> 6000 years ... 

A more expensive power strip is simply the same circuit and same protection found in a $7 grocery store protector. But it does have a big buck warranty that will not be honored. Anything that a UPS would accomplish is already inside the laptop. Those who did not grasp "floating neutral" also make protection recommendations. When an urban myth is popular, even the most electrically naive suddenly become experts.

Solution that better protects a laptop means protection for everything at $1 per protected appliance. One 'whole house' recommendation that actually improves laptop protection. Unlike others, this recommendation comes with numerous reasons why, without a warranty chock full of fine print exemptions, and from one with a few generations of professional experience.


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## valis (Sep 24, 2004)

JohnWill said:


> In the US, most residential power is 230V with a neutral center tap from the transformer. This is how 115V is obtained, connections between the neutral center tap and one of the hot legs from the transformer. If that neutral line is broken, a _floating neutral_ is the result. Now, any 115V device has to have it's common return through other devices on the opposite side of the transformer. If the loads aren't balanced (they rarely are), the result will be that one side of the 115V feed has a much higher voltage than the other side. It's the same as connecting two resistors in series to a power supply. If the resistances are unequal, one side will have a greater voltage drop.
> 
> 230V devices switching on and off will also change the voltage balance, it's interesting to watch.


John, you lost me about 7 words in.  I'm serious, electricity is a realm that I am completely and utterly deficient in. I got cooked as a kid pretty bad, and once bitten twice shy. I'll study what you wrote and of course learn from it, but if that was the dumbed down version for me, you are going to have to try a LOT harder.


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## valis (Sep 24, 2004)

w_tom said:


> If it costs more, then you have numbers to show that "better". No number and no manufacturer specs are provided because numbers say otherwise. That $60 protector is same as the $7 protector.


and again, I beg to differ, but I'm not going to sit here and argue the point all day. You obviously know far more than I when it comes to electricity, but unfortunately, that ain't saying a whole lot. My level of expertise with electricity is on par with that of, say, a golden retrievers.

That having been said, I have had the lovely job of installing dozens of networks on dozens of ships for the company I work with. If you have had any experience with big boat (or ships, forget what you are supposed to call the big ones) you'll know that the juice coming off the generator is not exactly clean; after a few hiccoughs and blown mobo's, we started going with the standard apc shoebox upc/ surge protector. It conditions the juice as it comes in, and serves as a wimpy backup battery when power drops.

Now, that one is over a hundred bucks. I do not know enough of the product or the electricity to argue with you on a 10 dollar version vs a 60 dollar version, so I'll take your word as I have no reason not to. I will say that it somewhat surprises me, but at the same time it doesn't, as I am very, very familiar with marketing, unfortunately. 

Whatever. If it works, it works, and I can definitely say that I've probably learned about a year's worth of high school electricity 101, so thanks all around. 

AND I didn't get zapped.


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## w_tom (Nov 29, 2008)

valis said:


> ... the juice coming off the generator is not exactly clean; after a few hiccoughs and blown mobo's, we started going with the standard apc shoebox upc/ surge protector. It conditions the juice as it comes in, and serves as a wimpy backup battery when power drops.
> Now, that one is over a hundred bucks.


 We saw this often. Equipment bought on price. Therefore a computer supply that must make 'dirty' electricity irrelevant, instead, did not. Computer power supplies are required to be that robust. Saving $20 or $30 on a cheap supply then required $hundreds in electrical conditioning hardware. Curing symptoms rather than addressing the problem - the person who cut costs - the bean counter mentality.

A solution starts by first locating the problem rather than throwing $hundreds at its symptoms. If motherboards were being zapped, the technical informed first discovers what is being zapped - then why. What is the power supply's job? To make irrelevant any 'dirt' from AC mains. Nothing output by a power supply must ever zap a motherboard. That was even standard in the 1960s - hinting at how far my experience goes.

A $100 UPS connects a computer directly to AC mains. No filters. No magic conditioning. Only a relay that switches over to battery when voltage drops. That confirmed using an oscilloscope to first and also find the problem. 

ATX computer specs are even blunter. Nothing output by a supply can harm a motherboard. Lights can dim to less than 40% intensity and a computer must still work just fine. Just another function that all computer power supplies must provide.

If a technical purchaser has an accountant's mindset, then a power supply may be missing numerous required functions. He saved $20. And so $hundreds are spent, instead, curing a symptom traceable to his cost control mindset.

Laptops are even more robust. Whereas a computer may be harmed by a constant AC voltage peaking at 300 volts, a laptop is perfectly happy. That $100 UPS would simply leave a computer connected to that 300 volts until excessive voltage harmed the UPS's supply. That $100 UPS would do nothing except maybe also fail.

A $100 (computer grade) UPS only provides battery backup power during blackouts and extreme brownouts. Read its numeric specs. It does not claim to eliminate spikes, harmonics, noise, or other electrical problems. Worse, in battery backup mode, it outputs some of the 'dirtiest' electricity with spikes and harmonics (as described earlier with numbers). That UPS power is so 'dirty' as to be harmful to power strip protectors and small electric motors. But computers and laptops are more robust. Therefore it is called a 'computer grade' UPS ... because its power is so 'dirty' when in battery backup.

Technology takes longer to explain than popular urban myths. Superior UPS functions exist inside laptops which is why a UPS (not to be confused with a building wide UPS) also does nothing useful for Tammy's laptop.


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## valis (Sep 24, 2004)

w_tom said:


> We saw this often. Equipment bought on price. Therefore a computer supply that must make 'dirty' electricity irrelevant, instead, did not. Computer power supplies are required to be that robust. Saving $20 or $30 on a cheap supply then required $hundreds in electrical conditioning hardware. Curing symptoms rather than addressing the problem - the person who cut costs - the bean counter mentality.
> 
> A solution starts by first locating the problem rather than throwing $hundreds at its symptoms. If motherboards were being zapped, the technical informed first discovers what is being zapped - then why. What is the power supply's job? To make irrelevant any 'dirt' from AC mains. Nothing output by a power supply must ever zap a motherboard. That was even standard in the 1960s - hinting at how far my experience goes.
> 
> ...


okay, got all that, and proved myself right that you know a bit more about this than I do. But I can put a reader on that boat I was telling you about, plug it into any outlet and just watch that thing swing left to right. And that's while she's at dock, mind. Engines idling.

What I was told (and that's all I have to go, as I am from colorado, biggest body of water there you can either step over in the summer or skate on in the winter) is that ships are notorious for have dirty juice coming off their generators. The older the ship, the worse the issue. This ship dates back to good ol' 1982. Hello Knight Rider and A-Team.

So let me ask you; do you think that the info I got was incorrect? I'm not trying to be wise here; remember, I freely admit that ships AND electricity are two things I can't really argue about because I don't know squat about either of them. But the info I got was from a guy who is 53 years old with over 30 years as captain; one of the youngest captains for this type tonnage (big as hades, IMO) in US maritime history. He's seen it all over the past 30 years, and going out to dinner with him is a treat, because of the stories he can spin. Guy can't be over 5'6" tall (actually wanted to be a professional jockey, but got too big for that) (daughter IS a pro jockey) but he's the dude you would either want on your side or keep one eye glued to in a bar fight. When he tells me that ships are notorious for having dirty juice, and the older the ship, the worse the problem, I tend to believe him.

But I'd love to hear yours or JW's input on it. As I said, what I don't know about the two could fill a warehouse quite easily.

Matter of fact, I got 12 of them filled with what I don't know out back already.

v


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## w_tom (Nov 29, 2008)

valis said:


> So let me ask you; do you think that the info I got was incorrect?


  The information would be correct. However the term 'dirty' is a basket for numerous unrelated electrical anomalies. For example, a typical $100 UPS has serious problems when operating off a cheap generator. Variations from some generators cause some UPSes to constantly switch to battery backup mode - never recharge. Computer might work fine directly from that power source, but UPS refuses to charge. It measures 120 VAC. But an electrical characteristics cause a UPS to believe no electricity is present. Many spend a little more money for a Honda generator that outputs 'cleaner' power. But moreso eliminates the reason why that UPS does not work with some 'dirty' power.

 Some power supplies may be missing required line filters. These filters serve many purposes including FCC regulations. European supplies may also include active filters so that a power supply does not generate and is more immune to harmonic problems. IOW 'dirty' power can be any unrelated conditions. Whereas 'UPS in battery backup' is not harmful to computers, that same power may be harmful to power strip protectors. Whereas low voltage (a completely different 'dirty') would be harmful to electric motors, it is not harmful to electronics.

 The problem is not 'dirty' power. The problem is which 'dirty'.

 A 'dead body' is always best evidence. An autopsy can identify what caused a failure. But destructively 'dirty' AC mains harms power supplies - not the load supplied by a power supply.

 Safety ground wire means destructive currents can bypass a supply and the motherboard's protection. IOW a motherboard is directly connected to wires ranging elsewhere on the ship. If safety ground is somehow compromised elsewhere, that may explain motherboard failure.

 But again, 'dirty' electricity is a summary word for numerous unrelated problems. If ship electricity is 'unstable', that is the perfect time to be using an oscilloscope. For example, to find an undesirable current flowing from a safety ground wire, through motherboard, to something else. Yes, it is an interesting mystery. One that cannot be solved from contemplation without further information. One that can be 'fun' - depending on who one is.


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## valis (Sep 24, 2004)

well, that 'one' ain't gonna be me. I'll gladly pay you a few hundred bucks, I'm assuming you've got several oscilloscopes laying around, and the next time this particular vessel makes it back to Galveston, why, I'll even follow you around and listen to you talk. Heck, you play it right, you may get a lunch out of me.


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## w_tom (Nov 29, 2008)

You do not need me to do an analysis. The world has people who actually know this stuff - even own oscilloscopes or a simple digital meter that now does same graphics. Meanwhile, anyone without basic electrical knowledge should not be making electrical recommendations.

 Demonstrated in a previous post are a long list of electrical anomalies that can cause operational failure or damage. No 'magic box' solution to all anomalies exists. When one promotes a single device for all problems, then a consumer should recognize symptoms of recommendations without learning basic concepts.

 A solution without also identifying the problem too often results in curing symptoms. Same reasoning even resulted in seven Challenger deaths.

 Essential to any responsible recommendation are underlying reasons why. Especially numbers. A recommendation made without underlying facts and numbers is the symptom common in scams, junk science, and 'Saddam had WDMs'. We all learned what happens when claims exist without those facts and numbers. One need only consult a manufacturer's specifications to learn what it actually does; to see through half truths printed in color glossy sales brochures. Effective surge protection means it lists each type of surge with numbers that define the protection.

 Surge protectors are for one type of anomaly. Another anomaly called 'open neutral' requires a different solution that must exist in every building (according to code), but is too often missing. A protector will not alleviate this problem. But the same thing essential to an effective 'whole house' protector is also the short term solution to an 'open neutral'. Just another example of why solutions always require answers with numbers and reasons why.


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## valis (Sep 24, 2004)

w_tom said:


> You do not need me to do an analysis. The world has people who actually know this stuff - even own oscilloscopes or a simple digital meter that now does same graphics. Meanwhile, anyone without basic electrical knowledge should not be making electrical recommendations.
> 
> Demonstrated in a previous post are a long list of electrical anomalies that can cause operational failure or damage. No 'magic box' solution to all anomalies exists. When one promotes a single device for all problems, then a consumer should recognize symptoms of recommendations without learning basic concepts.
> 
> ...





> A solution without also identifying the problem too often results in curing symptoms. Same reasoning even resulted in seven Challenger deaths.


what was the problem that resulted in the Challenger situation? That is a failure in engineering that I eminently familiar with, and last I checked, it was the o-rings not functioning in below freezing weather. NASA knew of this problem, and had known about it, for several years. They simply failed to address the issue.

But as far as NASA was concerned, there was never any doubt as to the integrity of the o-rings in sub-freezing weather. This is all public knowledge in the Rogers Commission. How does that tie in with dirty electricity coming off a ships generator?

Back to the original issue; we have a 30 year old ship that produces dirty juice out of her generator. We went through several motherboards before I came on hand and was given the problem. Among the first things I had them check in the investigation was the juice, and I personally spoke with with the Captain, who had told the IT personnel in charge of maintaining our fleet for years that it was dirty power coming off of the generator that was cooking these motherboards. I held a meeting in which the CIO of the company, the Captain and the vessel's electrician were present, and said this is the problem, how to fix it? The ships electrician said that his personal laptop was hooked up to a line conditioner that was also a UPC. So was the Captain's. At the time, both had been aboard the vessel for well over 5 years with no computer related issues.

I ordered two dozen of the identical UPS's, two for each machine on board, problem solved.

So I guess I don't know what you are saying.

I'm looking at a real world problem here with a real world solution that, if I am reading you right, is completely against what you recommend. I trust your input; you've been doing this since I was in diapers. But I am also saying that those line conditioners that the ship's electrician reco'd seem to have done the job. I've been here 4 years now, and not a single blown mobo has come off of that ship.

I think we are looking at the same problem only from different angles.

thanks,

v


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## w_tom (Nov 29, 2008)

Challenge is to identify the problem. Obviously you don't want to sacrifice motherboards to determine where the problem does and does not exist - what does and does not solve it.

Meanwhile, what makes other sensitive electronics (ship radio station, navigation electronics, clocks, etc) also immune to this 'bad' power?

Studios that want power even cleaner purchase a serious line filters that is beyond what must be standard inside all electronics. See .coms such as zerosurge, surgex, or brickwall. These may be a useful; are a more robust solution.

If the UPS is doing something protective, then quite likely a few MOVs are sufficient. Those $0.05 parts (selling retail for as much as $2 in Radio Shack) may also do the actual 'cleaning'. A $7 protector sold in the grocery store has the same protector circuit inside a UPS. But again, solutions without any practical way of confirming a solution since nobody wants to risk a motherboard.

How do those other electronics work without damage? IOW someone must have solved the same problem before you.

Finally, diagnostics tools. A cheap stereo with its inferior power supply may permit anomalies to be heard in its speakers. A tool to hear the anomoly, then connect it to various solutions to hear what eliminates and what does that job better.

I have never done this, but this might be a good diagnostic tool. A 2 watt speaker (from Radio Shack or any cheap radio), a 4 watt or 7 watt incandescent night light (from a Dollar store), a quarter or half amp fuse, and an AC power plug all connected in series. And a box to safely hold this circuit. Connect this series circuit between various AC prongs. Hot to neutral (the typical 120 VAC), Hot to ground, and neutral to ground. Most should result in a low, smooth hum. Spikes would create higher frequency or raspy sounds. This tool may hear the electrical anomaly. Then connect it to various 'solutions' to learn what removes that anomaly sound. Construct and test this tool before trying it on ship.

A seven watt bulb may be too small. You may need two or three in parallel or a twenty five watt bulb to make sufficient noise. Again, I have not done this. Experimenting (and watching accidental electrical fireworks) may be useful or only entertaining.

Should this make you nervous, test the circuit first on a GFCI protected circuit (kitchen or bathroom) so that accidents can never cause you a surprise.


Challenger. Previous shuttle flights had almost suffered a same failure. But those flights did not explode. Therefore no problem existed - according to management that could not bother to first learn the seriousness of what occured. Therefore a backup O ring became the solution. Not one engineer said it was safe to launch. So the solution was "it worked before, we don't care why." They launched by ignoring the underlying reasons why.

Responsible engineering identifies a problem, then solves it. Just because something works (ie previous Shuttle flights did not explode) is not proof that a solution is sufficient. 

Apparently a solution also exists elsewhere so that sensitive bridge electronics operate without problems.


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## valis (Sep 24, 2004)

w_tom said:


> Challenge is to identify the problem. Obviously you don't want to sacrifice motherboards to determine where the problem does and does not exist - what does and does not solve it.
> 
> Meanwhile, what makes other sensitive electronics (ship radio station, navigation electronics, clocks, etc) also immune to this 'bad' power?
> 
> ...


well put. There are many other sensitive electronics onboard before my minuscule computers go on. And you must be correct, that somebody notice this as an issue and either solved at the other end or compensated for it out the output end. IMO, it was a compensation deal, because if it was fixed at the source, it wouldn't have any issues across the vessel.

You are correct. This is a fun puzzle. I had completely forgotten about the other electronic devices aboard. But the fact does remain. Once that variable about the UPS's was cleared, we stopped frying motherboards. Now I know how sensitive system boards are. The zap you generate walking across a carpet can and will kill a system board. I've both done it and seen it done. So we know we are dealing with ultra fine soldering here.

Interesting puzzle. I'll see if I get any bad pc's back from the boats. I'm no longer overseeing the vessels, but next time I hear of a pc coming back from a ship for any reason I'll be sure to look into it, and if looks to be power related, you can bet it will be in my office awaiting yours and JW instruction as to what to look for wrt bad power killing the pc.

Now then. On to the shuttle.



> Challenger. Previous shuttle flights had almost suffered a same failure. But those flights did not explode. Therefore no problem existed - *according to management* that could not bother to first learn the seriousness of what occured. Therefore a backup O ring became the solution. Not one engineer said it was safe to launch. So the solution was "it worked before, we don't care why." They launched by ignoring the underlying reasons why.
> 
> Responsible engineering identifies a problem, then solves it. Just because something works (ie previous Shuttle flights did not explode) is not proof that a solution is sufficient.
> 
> Apparently a solution also exists elsewhere so that sensitive bridge electronics operate without problems.


I bolded the only relevant part that matters. The management overrode the engineers and that was that. EOD, end of discussion. From none other than Richard Feynman, a quote from his appendix (F) to the Rogers Commission:



> It appears that there are enormous differences of opinion as to the probability of a failure with loss of vehicle and of human life. The estimates range from roughly 1 in 100 to 1 in 100,000. The higher figures come from the working engineers, and the very low figures from management. What are the causes and consequences of this lack of agreement? Since 1 part in 100,000 would imply that one could put a Shuttle up each day for 300 years expecting to lose only one, we could properly ask "What is the cause of management's fantastic faith in the machinery?"


Again, management. I don't know how to sugar coat this or what not, but the bottom line is that the factors that attributed to the failure were managerial; i.e., the voices of the engineers were completely overridden and silenced, and the NASA management gave the green light when it simply had no right to do so.

Bottom line, the Challenger never should have even been on the pad that day. I'll let it stand at that.

v


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## w_tom (Nov 29, 2008)

Richard Feynman's book (they all are amusing) should be 'must reading' for anyone - especially for business school graduates. Especially those in GM who were routinely stifling innovation in the name of cost controls. BTW, every major innovation in a GM product this past 30 years could not occur until required by government regulation. That reality (like every engineer said to not launch) is often unknown to the public majority.

 Static electricity: semiconductors can easily be damaged by tens of volts. Then as integrated into systems, those same semiconductors can withstand 2000 and 15,000 volts without damage. Those numbers from international standards for what interface semiconductors must now confront without damage.

 Appreciate why wrist straps are so necessary when working on electronics. Once removed, protection is diminished or temporarily eliminated. Wrist strap wired so that charges located under the feet (that is the relevant ground not to be confused with receptacle safety ground) are discharged on a path that does not go through electronics.

 Static electricity is also a powerful diagnostic tool. For example, use leather slippers to maximize a static discharge, then discharge to various corners of the chassis. Computer must never crash (let alone have damage). Better assembled computers easily pass that test. However, for the test to be useful, the computer should be located on a glass table. Other materials such as wood are too electrically conductive - would undermine the test.

 If that static electric discharge causes any software crash, then the solution starts with how that computer is defectively assembled.

 Static electric discharges can also identify improperly safety grounded circuits. Properly wired circuits mean more pain during the discharge. 

 In one location, an industrial machine was crashing when they touched a switch. First, a new floor wax created static electricity. Second, metal was epoxy painted where the switch mounts therefore eliminating standard static protection. Just another example of a 'fun' problem.

 Should those series filters (brickwall.com, etc) prove useful, then maybe hardwire one in engineering spaces for everything on selected circuits. Another possiblity - how is the safety ground wire routed back to the generator? Unfortunately, too much 'fun' and often insufficient time.


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## valis (Sep 24, 2004)

interesting stuff. All of it. Me and you need to sit down and have dinner some and put the tab on JohnWill chit. He can afford it.

All I know is that I leave the electrical stuff to the guys who really understand it, and deal with everything else.

Too much crazyness going on in there.


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## JohnWill (Oct 19, 2002)

valis said:


> interesting stuff. All of it. Me and you need to sit down and have dinner some and put the tab on JohnWill chit. He can afford it.


And one wonders why we spend so much time discussing computer security and identity theft.


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## valis (Sep 24, 2004)

well, *I'm* certainly not the retired jet-set high-falutin' plane building type that some us are. I'm a working schlub with a toddler. 

In short, I have no money, and to top it off, I have no time.

Besides, I never said you weren't invited, now, did I?


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## JohnWill (Oct 19, 2002)

When it's my wallet, I issue the invites!


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## valis (Sep 24, 2004)

picky, picky. sheesh. 

next thing you know it's going to be the whole 'they are my bullets and my gun, so why are you firing it again' thing ALL over again.......


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