I do not see where “all DC voltages are perfect.” I have not seen what is inside computer power supplies but I have had to work with other power suppliers or converters.
Let me describe what I normally see. Lets start wirh the out put voltage different the input voltage. The first component is a transformer to convert the input voltage to the proper voltage of the out put. Then rectifires one or more convert the AC to DC. On some units caps are used to smooth out the voltage.
The out put voltage will be determined by the RMS value of the input. If the input RMS voltage drops the output will drop the same %.
What is this converting high voltage to radio waves? That seems very inefficent. Can anyone else verfy this or can you give me a link.
One other that thing I question is Claming that no energy needs to be dissipated by a “A short (ie ‘less than 10 feet’) connection via a ‘whole house’ protector.” If the device is grounded with single 0 wire, single 0 is good for 100 amps. Sorry but I do not have an Ugglys handy and I do not know the resistance per foot maybe you do. The watts will be I2R. 20,000 squared is a big number, the resistance is a small number. But some energy will have to be dissipated.
I’ve used lightning surge protectors for specific peices of valuable equipmnet in an area with a lot of lighting., They are NOT designed to handle direct strikes. Even with the 15 foot copper rod we drove into the ground and attached to the main ground via a 00 guage copper wire. What they will protect against is induction from a lighting strike. I forget the joule ratings on the units, but I can tell you this – they have prevented a lot of equipment damage as right after I installed them we got nailed with a nasty thunderstorm with a lot of close ground strikes. We had to restart some equipment, replace a couple fuses and replace at least 1 of the lightning surge protectors, but every single peice of protected equipment survived the storm. And the area gets the same kind of storms all summer long. Yeah, they have to replace the lightning surge protectors sometimes as when the surge is too much for it, the surge protector will blow out. But by doing that it still protects the equipment. However, on a direct stirke, all bets are off.
You have described a power supply that was obsolete long before the IBM PC existed.
How the first IBM PC power supply worked: AC is filtered by something that often exceeds what a power strip protector might do. Then converted to a higher voltage DC. Then filtered again. Then converted to a high voltage radio wave. Notice no transformer that would massively increase both weight and cost.
High voltage radio waves are galvanically isolated, filtered but another time, and converted to a high current radio wave. Then converted to low voltage DC. Then filtered again. All this means less expense, lighter, smaller, and more robust supply.
Also misunderstood is what makes (is required for) surge protection. Resistance is irrelevant. Impedance is extremely important. Wire diameter that mostly determines resistance is less relevant. Low impedance, mostly determined by wire length, sharp wire bends, splices, metallic conduit, etc is critical to surge protection. Impedance is why earthing must connect as short as possible (ie ‘less than 10 feet’).
For example, Polyphaser has a protector with no connection to earth. Distance to earth is so critical that the protector mounts on earth ground. Zero feet to earth. Distance is that important. A ground wire inside metallic conduit even compromises protection.
Most do not learn this. An 18 gauge (lamp cord) wire rated for 10 amps will conduct up to 60 amps continuously. Same wire can conduct a surge of up to 60,000 amps. Electrical parameters that say why earth ground must both meet and exceed post 1990 National Electrical code requirements.
Appreciate relevant concepts that you are probably hearing for the first time. Take a long wire antenna connected to a 200 watt transmitter. Touch one part of that antenna to receive a shock exceeding 100 volts. Touch another part to feel zero volts. How does the same wire have voltages so different at two locations? Electrical concepts irrelevant to electricians are quite important to surge protection.
Plug-in protector manufacturers hope you never learn this. Fundamental facts understood for the past 100 years also explain why plug-in protectors do not even claim protection from typically destructive surges. By having consumers uneducated, they can sell a similar $7 protector in a grocery store even for $80 and $150 using fancy paint and marketing hype. They need to consumer to remain that naive.
Defined, using what Ben Franklin demonstrated, is why effective surge protectors always have a dedicated and short wire to single point earth ground. Can earth direct lightning strikes without damage. Defined is why low voltage causes electronics damage only in folklore. Defined are electronics so robust as to not be damaged by anomalies that may be harmful to power strip protectors and motorized appliances (low voltage, ‘dirty’ power from a typical UPS). Defined is the only protector that actually does effective protection (with the always required and dedicated wire for earthing). And introduced are well understood and relevant electrical concepts that are often unknown to electricians and layman (ie impedance and where energy must dissipate). Most are probably hearing this for the first time.
But most important is a concept necessary for avoiding scams. A recommendation without the always required reasons why - and especially numbers - is a first indication of urban myth or junk science.
How to get others to recommend an ineffective protector. Grossly undersize it. Then during a surge, that protector will disconnect as fast as possible. Abandon a surge connected to the appliance. No problem. A surge that easily destroys an ineffective protector is also too tiny to overwhelm protection already inside the appliance. The appliance protected itself. But a naive consumer will recommend the grossly undersized protector.
That is good. A $3 power strip with some ten cent parts sells for $25 or $60. Obscene profit margin will create wealth. A consumer recommends it because it was grossly undersized. Even better because plug-in protectors are only profit centers. Do not even claim protection in their numeric specs.
If a protector blows out, then it disconnected as fast as possible. Did not do surge protection.
Be very concerned of protectors that are designed to fail even on surges too small to harm the adjacent appliance. If you have one, then a ‘whole house’ protector is needed to protect it. Effective protectors remain functional during and after a direct lightning strike. As was standard long before anyone here even existed.
One can waste massive sums on plug-in protector. Or spend about $1 per protected appliance for one ‘whole house’ protector. A superior solution that also costs tens of times less money.
While westom seems to understand the basic idea of a modern computer type power supply, the details are a bit off. There are no radio waves involved.
The incoming voltage is rectified and filtered, and then fed into high frequency oscillators. The power goes through transformers, which go to another stage where they are rectified and filtered through a switching regulator type of circuit. The idea is that by using high frequency oscillators (not radio waves, as westom seems to think they are) the transformers can be made much smaller and lighter. Typical frequencies for this stage of the power supply are in the 40 kHz to 200 kHz range. While these frequencies are in the low radio wave range (which is where I think westom’s confusion comes from) they are not fed to an antenna to make radio waves, but are instead transformer coupled into the secondary rectifier stage of the power supply.
Also, despite westom’s claim that the simple linear supply you described is obsolete, it is far from that. Switching power supplies have a few drawbacks. Despite westom’s claim that DC voltages are somehow “perfect”, the fact is that switching power supplies in particular are electrically very noisy. They tend to have artifacts from the oscillator stage as well as chopping artifacts from the switching regulator in the final output. Switching regulators also don’t work very well if they don’t have a minimum load on them, which is typically about 10 percent of their rated maximum. A third issue is cost. Switching power supplies are much more complicated and therefore much more expensive than a linear power supply.
Switching power supplies are much more efficient than linear power supplies. A switcher will typically be about 90 to 95 percent efficient, where a linear power supply can end up converting as much as 50 percent or more of the incoming power into waste heat. However, linear power supplies can handle a much wider load range (they tend to regulate properly all the way from their maximum load down to zero load) and their outputs contain significantly less noise.
I’d recommend that any further power supply discussions be spawned off to another thread so as not to hijack this one.
What probably happened (assuming lightning) was a lightning strike to a pole or primary power line. The spike in voltage would open a device called a “recloser”, an electronic device that monitors voltage and amperage in a certain line and opens if there is a fault, surge, or ground-fault. This in turn causes a device called a “lightning arrestor” to fault, or shoot the voltage to the ground via a wire down the pole. Then the recloser attempts to ‘reclose’. If the voltage/amps are nominal it will, otherwise it will stay open - sending a signal to the utility that it is open.
The crack you heard is most likely the lightning arrestor being blown (typically sounds like a gunshot or loud crack)
Your intent is correct. But knowledge of how it works has minor flaws. Surges are done in microseconds. That recloser takes milliseconds or even seconds to open. Reclosers are not tripped by a surge. Reclosers trip so long after a surge no longer exists.
A surge that does not create a short circuit trips no recloser. But a surge that creates, for example, a plasma short circuit eventually trips a recloser. Plasma short circuit - not the surge - creates the fault. AC mains electricity maintains that plasma fault (for same reason that fluorescent light bulbs work). AC utility electricity must be removed so that the plasma fault clears.
Surge arrestors trip in nanoseconds to connect a surge current (ie lightning) to earth. A surge arrestor works only if properly earthed. (Transformer requires earthing for this same reason.) Connection to earth made in nanoseconds. Reclosers take thousands or a million times longer. And do not stop a surge current. Reclosers provide time for the resulting plasma short circuit to dissipate (to become a gas).
Reclosers for overhead wires may operate differently from reclosers for underground wires. Different types of failures.
40 to 200 Khz is a radio wave. You are assuming radio waves only exist in air. Radio waves exist on the air, in waveguides, or on wires - which we also call xDSL.
Converting high voltage DC to high voltage radio waves means a transformer is massively smaller. Also provides superior galvanic isolation. Does superior filtering. Associated ‘noise’ is reduced significantly and more easily compared to 60 Hz ripple noise for obvious reasons. Noise from a switching power supply is so much less than ripple voltages from now obsolete technology supplies.
Meanwhile, in the 1970s, we needed a supply with less noise than an audiophile might need. Linear supplies with noise levels that tiny were not possible in any reasonable power, size, and cost. A superior solution was, again, a switching power supply that feed a now much less expensive linear regulator. Because noise was high frequency radio waves, then that linear supply needed less filtering to eliminate noise. Noise from that obsolete technology requires massive, expensive filters. Noise from a switching power supply is eliminated with smaller, tiny, and less expensive filtering.
Noise from the AC mains could easily pass through obsolete technology supplies. AC main noise is virtually nonexistent through a switching power supply. Therefore money spent on overhyped line conditioners is mostly wasted money.
Above is irrelevant to the original discussion. Standards for efficiencies and to make DC power cleaner all mean switching power supplies. Electronics work perfectly ideal even when incandescent bulbs dim to 50% intensity. A standard not possible with that obsolete technology and so much more expensive ‘line transformer’ supply. What was considered acceptable in the 1950s and 1960s is no longer acceptable today. Supplies most also perform many more functions – more reasons why switching supplies have replaced that obsolete technology supply.
All electronics must work normally even when voltages drop so low as to be harmful to motorized appliances. That supply also means electronic appliances contain surge protection that typically exceeds 1000 volts. More reasons why the best supply converts high voltage DC to high voltage radio waves.
Thanks for the info. Look at the handle that will explain my training. When I was taking classes eletronics were mainly vacuum tubes. I will honor your request and end here.
You guys are not listening to each other.
English is obviously not Westom’s first language.
Try to figure out what he is actually saying & not get all PC with your fingers in your ears.
Most of what you guys are saying seems right. Most of what he is ACTUALLY saying is mostly right. The words he is using are not bridging the gap and you all are not even trying to understand. And he is not explaining to well either.
My credentials is that I know lightning is strange stuff as I have been hit twice. You can look that up right here on the SDMB.
Amazing how much is accomplished inside today’s power supply. If your background is also vacuum tubes, then best is to start with a simple lesson on how buck and boost power supplies work. Maybe a half hour reading if it is a good primer.
A functional schematic will show a switch, a diode, a capacitor, and an inductor. The basic circuit is that simple. Many other functions get attached to that simplest circuit.
Actually, I am trying to understand what he is saying. He does seem to have some technical knowledge, but then other things he says are rather bizarre and don’t make sense at all from a technical standpoint even when you do factor in the language barrier. I can understand a language issue. That’s not a problem. What is a problem for me is his constant condescending and rude attitude. There’s no excuse for that no matter what his first language is.
One of the rules around here is don’t be a jerk. Since he insists on behaving that way, I will be more than happy to discuss the technical issues with anyone else in this thread, but I have nothing further to say to him directly and I will not be responding to his posts.
I had my order reversed, apologies. The lightning arrestor would send the surge to ground, thus causing the recloser to open/close, which caused the OP’s temporary loss of power.
Yes, one common way that power is temporarily lost. And why reclosers for overhead wires operate differently from those for underground distribution.
Sometimes a surge will clear itself without tripping the recloser. Sometimes a temporary disconnect by the recloser will clear that fault (ie plasma path). Sometimes the recloser tries to restore power multiple times. Then gives up leaving the circuit unpowered. Part of a protection system that includes arrestors and earth ground.
In one case, a transformer was not properly earthed. When a recloser opened, 33,000 volts had been shorted directly into a radio station already causing massive structure damage. And exploding that transformer. Only small pieces of the transformer remained. Greatest (potentially most destructive) energy can come from utility generated electricity.