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#1
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As a result of recent events, I have two surge protectors that no longer
function without putting out loud noises on HF. I found that the $5 surge protector that my Yaesu was plugged in to was making a loud whistling noise which was covered up by the louder warbling noise being made by the Belkin I had my computer plugged into. So I decided to break them open to see what was inside. The easiest was Old El Cheapo, held together with screws. Inside was a length of wire, a switch and ONE disc capacitor wired into six plugs. IMO that's little better than a plain old power strip. The Belkin had no screws, so it took a little longer to crack. The results: a switch, two LEDs ("protected" and "grounded"), an inductor coil, a couple resistors and transistors, and about 9 or 10 disc capacitors in series. In October 2002 the Belkin cost me $40. I'm hard pressed to say that it was money well spent, if all that's in there are some capacitors and resistors. Question: are surge protectors worth it if all they are is just a bunch of capacitors? I know that my $40 surge protector apparently rolled over and died when hit with a real surge. |
#2
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Are you sure the "disc capacitor" wasn't actually a MOV (Metal Oxide
Varistor) ? They look similar, but the MOV is a semiconductor device that drops in resistance when the voltage reaches a certain point. |
#3
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On Sat, 15 Nov 2003 0:15:46 -0600, tommyknocker wrote
(in message ): As a result of recent events, I have two surge protectors that no longer function without putting out loud noises on HF. I found that the $5 surge protector that my Yaesu was plugged in to was making a loud whistling noise which was covered up by the louder warbling noise being made by the Belkin I had my computer plugged into. So I decided to break them open to see what was inside. The easiest was Old El Cheapo, held together with screws. Inside was a length of wire, a switch and ONE disc capacitor wired into six plugs. IMO that's little better than a plain old power strip. The Belkin had no screws, so it took a little longer to crack. The results: a switch, two LEDs ("protected" and "grounded"), an inductor coil, a couple resistors and transistors, and about 9 or 10 disc capacitors in series. In October 2002 the Belkin cost me $40. I'm hard pressed to say that it was money well spent, if all that's in there are some capacitors and resistors. Question: are surge protectors worth it if all they are is just a bunch of capacitors? I know that my $40 surge protector apparently rolled over and died when hit with a real surge. Durn betcha! It did exactly as it should have and blew out the (I'm reasonably sure) capacitors (RadioShack used to carry them, btw)). That's why they are "cheap" - as I said earlier - they self-destruct rather than your computers or radio gear self-destructing. Stinger mentioned Standby Power Supplies. I have a 500 watt APC SPS that was pretty decently priced and my wife has one of the itsy-bitsy SPS Power Strips (APC Office 280) and I've seen these "PowerSupply in a Power Strip" /very/ cheap lately - 40U$-55U$. My wife and I used to run to the front door when the Back-Up 500 signaled with a short beep; usually we could get to the front porch to hear the transformer self-destruct. Sometimes we were the ones with a power outage and the two SPS's allowed us to "shut down gracefully". Other times we just knew that some residents not too far away had just lost their power. Gray Shockley ------------------------------------------------- They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown." - Carl Sagan |
#4
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not disc caps! they are metal oxide variable resistors. they look just
like caps. keep the shell and replace the mov's. it will be good as new. buy extras because the mov's can only take so many hits (or just one big one) before they are ruined. if you arent satisfied with the performance of the cheaper surge suppressors then look into a transformer based one. i have two ONAC brand line conditioners. they are more expensive but they never wear out. (excluding direct lightning hits of course) i got them surplus at a junk shop that salvaged computer equipment. its been more than ten years with out power line damage with my set up. i dont have $40 in both of them but i got lucky. when bought new they are not cheap. |
#5
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uh.... thanks for your very productive input barry O grady....... i am
sure that the english lesson was helpful in the understanding of line spike damping. oh by the way, god_freee_jones? i do not think freee is a word. use your spell-checker. |
#6
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Any protector that is damaged by the first surge is grossly
undersized. No effective surge protector can be damaged. They are not sacrificial devices as urban myth purveyors will claim. Why are 'whole house' protectors so effective? One reason: properly sized. For example, lets say that plug-in protector can withstand three same size 8/20 usec standard transients. Then the 'whole house' protector is rated to withstand on the order of 400 such transients. Properly sized protectors is but another reason why we install 'whole house' protectors and don't waste money on plug-in protectors. That 'whole house' protector costs about $1 per protected appliance. Why would anyone pay $20 or $50 for a plug-in protector that was both grossly undersized AND ineffective? Appliances already have internal protection. Sometimes surges are too small to even damage the appliance - but destroy the grossly undersized (and adjacent) surge protector. What kind of protection is that? Ineffective, overprices, undersized - and too often recommended by one who says, "My surge protector sacrificed itself to protect my computer". This is where ineffective plug-in protectors get recommended. Gray Shockley wrote: Durn betcha! It did exactly as it should have and blew out the (I'm reasonably sure) capacitors (RadioShack used to carry them, btw)). That's why they are "cheap" - as I said earlier - they self-destruct rather than your computers or radio gear self-destructing. Stinger mentioned Standby Power Supplies. I have a 500 watt APC PS that was pretty decently priced and my wife has one of the itsy-bitsy SPS Power Strips (APC Office 280) and I've seen these "PowerSupply in a Power Strip" /very/ cheap lately - 40U$-55U$. My wife and I used to run to the front door when the Back-Up 500 signaled with a short beep; usually we could get to the front porch to hear the transformer self-destruct. Sometimes we were the ones with a power outage and the two SPS's allowed us to "shut down gracefully". Other times we just knew that some residents not too far away had just lost their power. |
#7
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In article , w_tom
wrote: Any protector that is damaged by the first surge is grossly undersized. No effective surge protector can be damaged. They are not sacrificial devices as urban myth purveyors will claim. The characteristics of MOV's are well known. Every time a MOV turns on due to the device threshold being exceeded they degrade based on how much power is absorbed. If you are whom I think you are the facts won't bother you one bit and further nonsense posts can be expected. -- Telamon Ventura, California |
#8
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A wire also absorbs some power when it shorts a large
current. Does that mean the purpose of a wire is to absorb electricity? Of course not. MOVs are not installed to absorb power. But then if one first consults manufacturer datasheets, then that becomes woefully obvious. http://www.nteinc.com/Web_pgs/MOV.html Let's use the 2V130 as example. This device will shunt up to 4500 amps during the standard 8/20 usec surge. A 1000 volt transient at 4500 amps would be well over 600 joules. But this device is only rated at 39 joules maximum. How can that be? Because MOVs, like wire, are not installed to absorb the energy. They are designed to shunt. If an MOV was absorbing the transient, then MOV voltage must increase as more energy is absorbed. That means more voltage confronts the adjacent appliance. But MOVs don't work that way. If their purpose was to absorb a transient, then they must connect in series with the appliance. But MOVs connect in parallel - a shunt mode device. To be effective as shunt mode devices (like wire), the MOV must conduct massive transients and absorb less of that transient. That is what MOVs do. They shunt. They do not stop, block, absorb, or filter a transient. They operate like a wire during the transient. They shunt. As previously demonstrated from manufacturer datasheets (and not from wild speculation about what 'joules' measures): If that MOV in a plug-in protector that can only withstand 3 standard 8/20 microsecond transient, then the larger 'whole house' protector (that costs about same) will withstand about 300+ such surges. Joules is a measure of MOV life expectancy. MOVs are not designed to absorb a transient - which is in direct contradiction to what many web sites, written by English majors, will claim. The better an MOV, then the more energy it can shunt - per joule. Read manufacturer datasheets; not web sites written by English majors. It is the difference between fact and fiction. Now for your insults - which apparently are due to insufficient electrical knowledge. First learn before insulting others. There is a datasheet. Read it before posting. Keep it civil - if you can. Posted previously are accurate electrical engineering facts taken from manufacture datasheets. Any protector that is damaged by the first surge is grossly undersized - an ineffective protector usually sold to those who like to throw money at urban myths. BTW, MOV degradation is not due to power absorption. It is due to energy absorption - a major technical difference that English majors will not understand. Telamon wrote: In article , w_tom wrote: Any protector that is damaged by the first surge is grossly undersized. No effective surge protector can be damaged. They are not sacrificial devices as urban myth purveyors will claim. The characteristics of MOV's are well known. Every time a MOV turns on due to the device threshold being exceeded they degrade based on how much power is absorbed. If you are whom I think you are the facts won't bother you one bit and further nonsense posts can be expected. |
#9
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Mr. Sharp, there is no need for you to continue arguing with an idiot. You
are quite correct an have the documentation to prove it. "Clifton T. Sharp Jr." wrote in message ... w_tom wrote: |
#10
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![]() "w_tom" wrote in message ... [snip] If refrigerators and air conditioners were creating destructive surges, then all would be trooping daily to hardware stores to replace damaged dimmer switches, electronic timers switches, X-10 remote controllers, and touch on-off lamps. Surges created by refrigerators, et al are urban myth because you don't replace those other appliances daily. Well, who'd have figured? Here's a variation on that urban legand. Cut the current to an inductive load such as a motor, and it makes a surge of voltage! I'm so glad the clued-in know better. Furthermore if refrigerators, et al created those surges, then surge protector must be installed in that surge creating appliance - not on every other appliance. As all the Clueminati know, that's a big, big if. If refrigerators created those voltages in excess of 330 volts (as listed on surge protector boxes), then we must remove those appliances as a threat to human life. We don't remove those appliances because they don't create 'urban myth' surges. E-mail is certainly more responsible than appliances for the urban myth surges. We have the case down cold. MOVs have limited life expectancy as defined by joules. If refrigerators and air conditioners were creating destructive surges, then those plug-in surge protectors would be degraded in weeks or months without any indication of failure. What good is a $50 surge protector that must be replaced every month? Ineffective. I ruined my surge supressor by reading posts on AFU. HowStuffWorks on surge protectors has numerous technical errors. It begins accurately, but then makes serious errors. It preaches what plug-in surge protectors promote rather than the principles of surge protection proven in the 1930s. It preaches concept that if accurate, negate any need for 'whole house' type protectors. The author probably did not have sufficient knowledge to see through half truths promoted by his information source - plug-in protector manufacturers. Therefore HowStuffWorks is riddled with errors and misrepresentations. That's right. Don't trust advertising literature! Because plug-in surge protectors don't claim protection from direct lightning strikes, then instead HowStuffWorks claims most surge damage comes from refrigerators, et al. Demonstrated is that such surges don't typically exist. In reality, lightning is a most common source of surge damage - in direct contradiction to plug-in manufacturer claims and to text in HowStuffWorks. Surges occur typically once every eight years. Surges every eight years? Then I gotta ask Art Bell just what's ruining those surge supressors! HowStuffWorks provides so much wrong information that it should be outrightly avoided and should not be recommended - except to demonstrate how to promote urban myths. Example: since plug-in surge protectors don't claim protection from lightning, then an outright lie is declared: You know it, d00d!! Here's what the liar Wendell H. Laidley, President, Zero Surge Inc., wrote: "Myth #10. NOTHING CAN STOP LIGHTNING. While this simple statement is true in absolute terms" This is from: http://www.totse.com/en/technology/c...ogy/surge.html Well, he goes on to claim that his products offer better partial protection from induced lightning surges than the partial protection offered by the supressors offered by other companies. Well, I say protection and partial protection aren't exactly the same thing. I wish I could get one of those surge protectors the Clueminati use. Those supressors must throw the lightning bolts back into the clouds, where they belong. Actually lightning only overpowers the undersized surge protector sold by plug-in manufacturers. Visit real surge protector manufacturers to learn why man has shunted direct strikes without damage since before WWII. Man has shunted direct strikes without damage since before WWI. Man has shunted direct strikes without damage since before the Spanish-American war. Man has shunted direct strikes without damage since before the Civil War. Man has shunted direct strikes without damage since before the Mexican American war. Man has shunted direct strikes without damage since before the War of 1812. Man has shunted direct strikes without damage since before the Revolution. Man has shunted direct strikes without damage since Ben "Freemason" Franklin figured it out. But why? Why shunt protection when series protection is claimed to be better? And why is such manly knowledge parceled out by the manufacturers of real surge protectors? Must be a Clueminati thing. 'Whole house' protectors are properly sized to avoid lightning damage. HowStuffWorks is biased towards grossly overpriced, undersized, ineffective, plug-in surge protectors - that cannot protect from the most common source of surge damage - the common mode transient. Yes! Finally we get to the all damaging common mode transient! There are still morons who discount the dangers!! To quote from the idiotic, inane fools at the ZeroSurge website: "We can readily see the common mode surge risk is not just low, it is nonexistent." This is from: http://www.zerosurge.com/HTML/mode2.html Thank goodness the unnamed makers of Real Surge Protectors who know what the hell they are talking about. More errors are about those indicator lamps. The OK lamp does not report that a surge protector is functional. Remove all MOVs and the indicator lamp would still claim the surge protector is OK as demonstrated in these scary pictures: http://www.zerosurge.com/truth.htm Did Art Bell clip those out? HowStuffWorks provides so much wrong information that it should be avoided. Only a grossly undersized surge protector will fail catastrophically. Only catastrophic type of failures can be reported by the light. Properly sized surge protectors only degrade. A degraded surge protector will still indicate OK on that lamp. Indicator can report that a surge protector has grossly failed (because it was undersized) BUT cannot report that a surge protector is good. Scary pictures demonstrate this problem by removing all MOVs - and still the surge protector indicator lamp says it is OK: http://www.zerosurge.com/truth.htm HowStuffWorks has outrightly mislead about that indicator lamp since the English major did not really understand how that light works. They forget to mention that phone lines have been installed with 'whole house' surge protector for decades. Yes. The telco provides a 'whole house' protector on household phone lines - for FREE! Again propaganda from ineffective plug-in manufacturers that routinely forgets to mention, for example, that surge protection is earth ground. An effective surge protector only connects to surge protection - earth ground. A surge protector is not surge protection - as they would have everyone believe to sell their overpriced product. The HowStuffWorks article ignores the most critical component in all surge protection 'systems' - central earth ground. However *real* surge protector manufacturers discuss earthing extensively: http://www.polyphaser.com/ppc_technical.asp Why does HowStuffWork ignore fundamentals of surge protection? Why does it completely ignore the most critical component of a surge protection 'system'? Urban myths are common even though those fundamentals have been proven since the 1930s. Unfortunately, HowStuffWorks mixes accurate information with urban myths. For example, we are not replacing damaged dimmer switches and other appliances daily. Therefore refrigerator and air conditioner are not creating those damaging surges claimed by HowStuffWorks. Here's another related urban myth for 'ya. Underwriter's Labs requires electrical devices to withstand these surges or they don't get approved! The HowStuffWorks surge protectors article is chock full of such misrepresentations. So full of errors and misrepresentations as to best avoid. Fundamental to surge protection and not mentioned by HowStuffWorks - a surge protector is only as effective as its earth ground. HowStuffWorks does not even mention the most critical component in any surge protection 'system' - single point earth ground - because it is not discussing effective surge protectors. What can you expect? They hardly mention the miracle of shortwave radio!! Maybe you could write some clear articles about grounding and SW radio. Show those English majors a thing or two! Frank Dresser |
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