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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#81
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Surge Protectors
westom wrote:
On Jun 19, 12:25 pm, Jeffrey D Angus wrote: What the plug-in suppressors rely on is the impedance (generally inductive) in the house wiring to limit the rise time of thesurgeuntil the circuit breaker (or fusable parts) have time to react by opening up. And why Bud will not discuss wire impedance and earth ground. Poor westom's religious blinders prevent him from reading what gets written. I certainly have written about wire impedance in this thread. But if westom was not hampered by religious blinders he would read in the IEEE surge guide that plug-in suppressors do not work primarily by earthing. They work primarily by clamping the voltage on all wires to the ground at the suppressor. bud's citation Page 42 Figure 8 shows a plug-in protecting earthing a surge 8000 volts destructively through a nearby TV. He hopes you do not grasp the point in his IEEE citation. I hope everyone will "grasp the point" in the IEEE example. - The TV connected to the plug-in suppressor is protected. - "To protect TV2, a second multiport protector located at TV2 is required." So let's put numbers to it. Let's say the plug-in protector and TV are 50 feet of wire from the breaker box. That means it is less than 0.2 ohms resistance. And maybe 120 ohms impedance. So that protector will earth a trivial 100 amp surge? 100 amps times 120 ohms means the protector and TV are at maybe 12,000 volts. With minimal reading skills westom would have read that at about 6kV (US) there is arc-over at the service panel from bus to enclosure/ground - which is connected to the earthing electrode and neutral. After the arc is established, the voltage is hundreds of volts. The same thing happens at receptacles. This is a well established action for people who are familiar with surge protection. westom makes up a 100 amp surge on the branch circuit and 120 ohm impedance - won't happen together. Why did the protector earth that surge 8000 volts through the TV? And the lie repeated - 5th time? In the IEEE example - of how plug-in suppressors protect - the suppressor at TV1 causes absolutely NO damage to TV2. Why do telcos all over the world not waste money on bud's plug-in protectors? Ho-hum - because telco switches are high amp, hard wired, and thousands of phone circuits would have to go through the plug-in suppressor. Learn that no protector works by absorbing energy. True of service panel and plug-in suppressors (but they absorb some energy while protecting). If you put a MOV across a relay coil, it protects by absorbing energy. That is why the protector too close to appliances and too far from earth ground can even earth that surge 8000 volts destructively through a nearby TV. The lie repeated - 6th time? In the IEEE example the surge comes in on the cable service. westom has not explained how his service panel suppressor would provide any protection. That is because it would provide absolutely NO protection. With separated service entry points the IEEE guide says "the only effective way of protecting the equipment is to use a multiport [plug-in] protector." A majority only believe the advertising myths - that protectors magically make hundreds of thousands of joules just magically disappear. Only magic if you suffer from willful stupidity. IOW a protector is only as effective as its earth ground. Ho-hum - still never explained - why aren't flying airplanes crashing every day when they are hit by lightning? They must drag an earthing chain. Still missing - any reliable source that agrees with westom that plug-in suppressors are NOT effective. Still missing - answers to simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why does the NIST guide say "One effective solution is to have the consumer install" a multiport plug-in suppressor? - How would a service panel suppressor provide any protection in the IEEE example, page 42? - Why does the IEEE guide say for distant service points "the only effective way of protecting the equipment is to use a multiport [plug-in] protector"? - Why did Martzloff say in his paper "One solution. illustrated in this paper, is the insertion of a properly designed [multiport plug-in surge suppressor]"? - Why does Dr. Mansoor support multiport plug-in suppressors? - Why does "responsible" manufacturer SquareD says "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use"? - Why don’t favored SquareD service panel suppressors list "each type of surge"? For real science read the IEEE and NIST surge guides. Both say plug-in suppressors are effective. -- bud-- |
#82
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Surge Protectors
Jim Yanik wrote:
"David" wrote in - september.org: A MOV is somewhat like two back-to-back Zener diodes. It is a voltage clamp. no,it's not. it does not "clamp" the voltage. You do not pass energy to ground, you pass current to ground just like you do with any load. The energy is totally dissipated in the MOV. Uh,"passing current to ground" IS passing energy to ground. David totally wrong. Wiki has a nice article on metal-oxide varistor,I suggest you read it. -- Jim Yanik jyanik at localnet dot com Jim, I am not going to get into a flame war over this topic. Maybe you should check this out: http://www.cliftonlaboratories.com/metal_oxide_varistor_(mov).htm David http://en.wikipedia.org/wiki/Metal_oxide_varistor Varistors can absorb part of a surge. How much effect this has on risk to connected equipment depends on the equipment and details of the selected varistor. Varistors do not absorb a significant percentage of a lightning strike, as energy that must be conducted elsewhere is many orders of magnitude greater than what is absorbed by the small device. -- Jim Yanik This is my final say on this topic. In the quote above, you assume the section saying that "... energy that must be conducted elsewhere ..." goes to ground through the MOV. This is where your error resides. The energy is going elsewhere but being dissipated somewhere else completely such as blowing up a transformer. The article should also use the term dissipated elsewhere to make things clearer. feel free to edit it. You also assume that passing current is equivalent to dissipating energy. No,that's what YOU assume I said. Wrongly. Current can *move* energy somewhere, but electrical energy is only dissipated when the current causes a voltage drop. A perfect ground will not have a voltage drop so that is not where the the energy is being dissipated. HA,now you're talking about "perfect grounds".Sheesh. you don't know what you're talking about. I agree. The vast majority of energy in a lightning strike is passed on to the earth. Assume a surge of 10,000A on a service wire (maximum that has a reasonable probability), a very good resistance to earth of 10 ohms and a duration of 100 microseconds. If I am multiplying right that is 100,000 joules dissipated in the earth. If you had a service panel suppressor with UL let through voltage of 330V (measured at a specified current much lower than 10kA) the actual voltage across the MOV might be 500V and the energy dissipated for the same surge would be 500 joules. Most of the energy that was available at the cloud is dissipated on the trip down - in heat, light, sound.... In about any lightning strike there are multiple paths to earth - multiple utility earthing points, multiple houses, .... BTW,when a lightning strike hits a ground,it dissipates it's energy -in the ground-. literally. Nice example. It even makes a fulgurite.(fused earth) |
#83
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Surge Protectors
Jim Yanik wrote:
"William Sommerwerck" wrote in : "Cydrome Leader" wrote in message ... William Sommerwerck wrote: Many years ago, PC and/or Byte (I forget which) used to test suppressors. If they failed to provide suppression, I assume the mag would have said so. Hilarious, PC magazine is your source for the lowdown on surge supression devices? It was, 20 years ago. I don't think you get the point, though. So what is the point? John Dvorak wrote a story about surge supressors and how they worked with his Cumulus 386 laptop and his CompuAdd 486sx tower? The point is that they were performing lab tests on the suppressors. These tests included determining the clamping voltage. (I don't remember if they were tested to destruction.) The tests were presumably performed in accordance with industry-accepted standards. "clamping" is a misuse of the word WRT surge protectors. It misleads people,as in "david" s post. "trigger voltage" might more accurate. MOVs have a smooth, but nonlinear, curve from not conducting at low voltage to high conduction current at higher voltages. They do not "trigger" like a neon light. And the voltage across the MOV does not suddenly decrease, like it would in a neon light (you probably didn't say it did). "Clamping" is a widely used term, including the wiki article on MOVs. (Gas discharge tubes are like a neon light, and do trigger.) One of the parameters for a MOV is MCOV (maximum continuous operating voltage) which is the voltage at which the current is 1 mA. The increase in current is smooth (but very non-linear) above the MCOV, just like it was smooth (and non-linear) below the MCOV. (When the MCOV for a MOV decreases 10% it is the defined end of life for a MOV - referred to in the wiki article.) A MOV is very much like back-to-back Zener diodes, but does not clamp as sharply. But MOVs have huge current capacity in a small package. The clamp voltage that is usually cited is the UL let through voltage (UL calls it something a little different). This is the voltage at a specified test surge current. If the surge current goes up, the let through voltage will be higher (in a non-linear way). -- bud-- |
#84
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Surge Protectors
On Sun, 20 Jun 2010 14:39:27 -0500, Jeffrey D Angus
wrote: David wrote: http://www.cliftonlaboratories.com/metal_oxide_varistor_(mov).htm Amazing coincidence that they act much like the old NE-2 neon bulb across the antenna leads of old receivers for protection. They would conduct around 65 volts and suddenly go to near zero impedance, safely shunting what ever energy on the antenna line to ground. And although most receiver inputs couldn't handle a steady state of 65 volts (or 130 vpp), they could handle them long enough for the neon bulb to conduct and then shunt them to ground. We used to test our radios with 117vac on the antenna terminals. While not a required test, it happened often enough that it was worth testing and protecting. The AC plug to PL-259 test cable on my cable rack generated quite a few odd questions. Neon lamps, MOV's, back to back diodes, PIN diodes, and such are generally a bad idea in high RF environments. Any non-linear device between the antenna and the RF amp is going to act like a mixer and create the dreaded intermodulation products. MOV's and diodes are particularly bad because they start to slightly conduct at nearly zero voltage, and increase exponentially with increasing signal. The MOV also has 100-1000pf of unstable and unpredictable capacitance, which is not a good thing on the antenna input. The closest approximation of an ideal protection device are the one-time gas filled spark gaps used in lightning protectors. No conduction at all until they arc over. Then, they're dead. Question: What's the peak to peak output voltage of a 50 watt transmitter into 50 ohms? Answer: V = 2.828 * 50^2 / 50 = 141 volts p-p Now, do you REALLY want a device that conducts at 65 volts across the xmitter antenna terminals? I actually tried a varistor across the antenna terminals of an HF 150w PEP xmitter and confirmed the big bang theory. Hint: Things work differently at 60Hz than at RF frequencies. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#85
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Surge Protectors
On Jun 20, 1:36*am, Cydrome Leader wrote:
William Sommerwerck wrote: Many years ago, PC and/or Byte (I forget which) used to test suppressors. If they failed to provide suppression, I assume the mag would have said so. hillarious, PC magazine is your source for the lowdown on surge supression devices? It was, 20 years ago. I don't think you get the point, though. So what is the point? John Dvorak wrote a story about surge supressors and how they worked with his Cumulus 386 laptop and his CompuAdd 486sx tower? My news reader sees a problem in these postings .. Mark Waller wrote an article for Byte. I have his book PC Power Protection from 1988. Great reading. I should also have that mag article if anybody is interested. I should look it up. From worrying too much about protection, Mark is now a Family Therapist. greg |
#86
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Surge Protectors
On Jun 21, 11:19 am, bud-- wrote:
Poor westom's religious blinders prevent him from reading what gets written. I certainly have written about wire impedance in this thread. Bud promotes plug-in protectors. It is his job. Either that protector connects energy harmlessly to earth. Energy absorbed without damage. Or energy is inside the building - bud's IEEE guide Page 42 Figure 8 - hunting for earth destructively via appliances. 8000 volts destructively through the TV because bud's miracle protector cannot absorb destructive surges. bud's NIST citation also describes bud's "profit center" protectors: A very important point to keep in mind is that your surge protector will work by diverting the surges to ground. The best surge protection in the world can be useless if grounding is not done properly. No earth ground (bud's high profit protectors) means no effective protection. Even the NIST says so. All of bud's citations say that. Meanwhile IEEE Standards (the Red Book) - where the IEEE makes all recommendations - state what is always necessary for surge protection - and what bud denies: In actual practice, lightning protection is achieve by the process of interception of lightning produced surges, diverting them to ground, and by altering their associated wave shapes. Or IEEE Emerald Book: It is important to ensure that low-impedance grounding and bonding connections exist among the telephone and data equipment, the ac power system's electrical safety-grounding system, and the building grounding electrode system. ... Failure to observe any part of this grounding requirement may result in hazardous potential being developed between the telephone (data) equipment and other grounded items that personnel may be near or might simultaneously contact. Protection is always about where energy dissipates. That means an effective protector connects short (ie 'less than 10 feet') to single point earth ground. But somehow bud's protectors magically make energy just disappear? It is what he is paid to promote. It is why he gets angry. Reality would harm profits. Surge protection means energy dissipates harmlessly in earth; outside the building. A protector without that dedicated and short connection to earth does not claim protection in its numeric specs - as bud tacitly admits. So bud's protector magically makes that energy disappear? That is also what bud tacitly claims. |
#87
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Surge Protectors, how do you tell if they still good
On Jun 20, 3:54*pm, mike wrote:
I've been following this thread, and I got to wondering are there any accepted methods to tell if asurgearrestor setup is still usable as such? Assuming they are MOV based, read MOV datasheets to learn how MOVs work and obtain relevenant numbers for the test. Perform a 1 milliamp test to confirm these numbers on that protector. This test is described in some manufacturer application notes. The test only confirms the protector can conduct. Does not say anything about what makes a protector effective - the earth ground and how it connects to earth. The best surge protection in the world can be useless if grounding is not done properly. |
#88
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Surge Protectors
westom wrote:
On Jun 21, 11:19 am, bud-- wrote: Poor westom's religious blinders prevent him from reading what gets written. I certainly have written about wire impedance in this thread. Bud promotes plug-in protectors. It is his job. westom just continues to repeat the same lies - a la Goebbels. And the same misrepresentations - a la religious fanaticism. All the sources westom uses, including even his favorite manufacturers, say plug-in suppressors are effective. In particular, the IEEE and NIST surge guides both say plug-in suppressors are effective. Links have been provided to these reliable sources. There are 259,615,938 other web sites, including 23,843,032 by lunatics, and westom can't find another lunatic that says plug-in suppressors are NOT effective. Also still missing - answers to simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why does the NIST guide say "One effective solution is to have the consumer install" a multiport plug-in suppressor? - How would a service panel suppressor provide any protection in the IEEE example, page 42? - Why does the IEEE guide say for distant service points "the only effective way of protecting the equipment is to use a multiport [plug-in] protector"? - Why did Martzloff say in his paper "One solution. illustrated in this paper, is the insertion of a properly designed [multiport plug-in surge suppressor]"? - Why does Dr. Mansoor support multiport plug-in suppressors? - Why aren't airplanes crashing daily when they get hit by lightning (or do they drag an earthing chain)? - Why does "responsible" manufacturer SquareD says "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use"? - Why don’t favored SquareD service panel suppressors list "each type of surge"? Why can't you answer simple questions westom???? -- bud-- |
#89
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Surge Protectors, how do you tell if they still good
In article , westom wrote:
On Jun 20, 3:54=A0pm, mike wrote: I've been following this thread, and I got to wondering are there any accepted methods to tell if asurgearrestor setup is still usable as such? Assuming they are MOV based, read MOV datasheets to learn how MOVs work and obtain relevenant numbers for the test. Perform a 1 milliamp test to confirm these numbers on that protector. This test is described in some manufacturer application notes. The test only confirms the protector can conduct. Does not say anything about what makes a protector effective - the earth ground and how it connects to earth. The best surge protection in the world can be useless if grounding is not done properly. IEEE 587 and UL 1449 Talks of 3-6KV and 500 amps typical test produces eventual failure. greg |
#90
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Surge Protectors
In article , GS wrote:
On Jun 20, 1:36=A0am, Cydrome Leader wrote: William Sommerwerck wrote: Many years ago, PC and/or Byte (I forget which) used to test suppress= ors. If they failed to provide suppression, I assume the mag would have said = so. hillarious, PC magazine is your source for the lowdown on surge supres= sion devices? It was, 20 years ago. I don't think you get the point, though. So what is the point? John Dvorak wrote a story about surge supressors an= d how they worked with his Cumulus 386 laptop and his CompuAdd 486sx tower? My news reader sees a problem in these postings .. Mark Waller wrote an article for Byte. I have his book PC Power Protection from 1988. Great reading. I should also have that mag article if anybody is interested. I should look it up. From worrying too much about protection, Mark is now a Family Therapist. Here is the article. http://zekfrivolous.com/misc/waller.pdf |
#92
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Surge Protectors, how do you tell if they still good
westom wrote: Assuming they are MOV based, read MOV datasheets to learn how MOVs work and obtain relevenant numbers for the test. Perform a 1 milliamp test to confirm these numbers on that protector. This test is described in some manufacturer application notes. Been awhile since I looked inside, I'll have to open 'em back up and see what numbers are on them (if any, I can't remember). The test only confirms the protector can conduct. Does not say anything about what makes a protector effective - the earth ground and how it connects to earth. The best surge protection in the world can be useless if grounding is not done properly. Makes sense, I'll confirm that the service entrance ground is in good condition, too. Thanks, Mike |
#93
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Surge Protectors
On Jun 21, 1:40 pm, bud-- wrote:
westom just continues to repeat the same lies - a la Goebbels. An honest bud would simply post numeric specs to prove what he claims. He cannot. No plug-in protector claims that protection from each type of surge. bud is a promoter. He again posts insults because his protectors do not claim protection in numeric specs. Honesty is not bud. What do his citations show? Page 42 Figure 8. A protector too far from earth ground and too close to TVs earths a surge 8000 volts destructively through that TV. IEEE brochure Page 42 Figure 8 demonstrates why high profit plug-in protectors do not even claim protection in numeric specs. Bud’s job is to lie and insult so that you will ignore what he cannot provide - effective protection. Where are those numeric specs that claim surge protection? bud promotes these things – and still cannot find those numeric specs. |
#94
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Surge Protectors
westom wrote:
On Jun 21, 1:40 pm, bud-- wrote: westom just continues to repeat the same lies - a la Goebbels. An honest bud would simply post numeric specs to prove what he claims. An honest westom would admit that specs have been provided often in other threads, and through a link in this thread. And also by other people. Always ignored. An honest westom would admit that both the IEEE and NIST surge guides say plug-in suppressors are effective. An honest westom would not try to make sources say the opposite of what they actually say. An honest westom would admit he can't find another lunatic that agrees that plug-in suppressors are NOT effective. An honest westom could answer simple questions: - Why do the only 2 examples of protection in the IEEE guide use plug-in suppressors? - Why does the NIST guide says plug-in suppressors are "the easiest solution"? - Why does the NIST guide say "One effective solution is to have the consumer install" a multiport plug-in suppressor? - How would a service panel suppressor provide any protection in the IEEE example, page 42? - Why does the IEEE guide say for distant service points "the only effective way of protecting the equipment is to use a multiport [plug-in] protector"? - Why did Martzloff say in his paper "One solution. illustrated in this paper, is the insertion of a properly designed [multiport plug-in surge suppressor]"? - Why does Dr. Mansoor support multiport plug-in suppressors? - Why aren't airplanes crashing daily when they get hit by lightning (or do they drag an earthing chain)? - Why does "responsible" manufacturer SquareD says "electronic equipment may need additional protection by installing plug-in [suppressors] at the point of use"? - Why don’t favored SquareD service panel suppressors list "each type of surge"? Why don't you ever answer questions westom??? -- bud-- |
#95
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Surge Protectors
On Jun 9, 3:20*pm, Jeffrey D Angus wrote:
GregS wrote: I just checked, and its difficult to find surpressors that are cheap. I found one for $30 and might get a discounted price. This is a basic model.................. *http://www.grainger.com/Grainger/items/1ECD1?Pid=search Well, you can't say inexpensive andGraingerin the same sentence. You'll find the exact same products elsewhere for 25-50% less. Jeff -- Egotism is the anesthetic that dulls the pain of stupidity. Frank Leahy, Head coach, Notre Dame 1941-1954 http://www.stay-connect.com I finally hooked up a suppressor to the main box. I ordered the item from Drillspot, and received it from GRAINGER ! I also fooled around with my lightning arrestors on the deck outside. I want to keep surge protector also in the separate garage. I also need to put something in my LED lighting string around the house. That would be expensive to replace and difficult. |
#96
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Surge Protectors
In article , GS wrote:
On Jun 9, 3:20=A0pm, Jeffrey D Angus wrote: GregS wrote: I just checked, and its difficult to find surpressors that are cheap. I found one for $30 and might get a discounted price. This is a basic model.................. =A0http://www.grainger.com/Grainger/items/1ECD1?Pid=3Dsearch Well, you can't say inexpensive andGraingerin the same sentence. You'll find the exact same products elsewhere for 25-50% less. Jeff -- Egotism is the anesthetic that dulls the pain of stupidity. Frank Leahy, Head coach, Notre Dame 1941-1954 http://www.stay-connect.com I finally hooked up a suppressor to the main box. I ordered the item from Drillspot, and received it from GRAINGER ! I also fooled around with my lightning arrestors on the deck outside. I want to keep surge protector also in the separate garage. I also need to put something in my LED lighting string around the house. That would be expensive to replace and difficult. I find 90 volt gas discharge tubes. I could probably use a lower voltage device. I don't know what else would be self resetting. greg |
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