kiki_danc said:
If you will notice.. most 120v SPD type 3 has VPR of 600 volts average. 330V VPR is so rare. If 600V VPR can still damage equipments.. why would people still buy surge protectors?
Reflecting on it. Maybe even VPR of 600v is safe for 120v equipments because the surge only last 8/20 microsecond? Maybe this is not enough to heat the electronic elements.. it's not like voltage regulator where 600v is continuous. So I guess 6000v surge may damage electronics but not 600v surge?
Also we mostly hear about VPR... how come we never hear about let-thru current. For example if a UL 1449 3rd edition 6000v, 3000A 8/20 microsecond surge hit the MOV. Besides the VPR of say 600 volts.. what is the CPR (Current Protection Rating if there is such a phrase) rating or value. Does the 3000A become like 400A only or is it completely gone after it passed the MOV element.. zero residual current? For electronic circuits.. what can damage it more.. voltage surge or current surge? And what electronic components are directly damaged by any surge? the transistors, the ICs? How is it damaged? If current is what damaged it.. then VPR of 600v and CPR (Current Protection Rating) of zero may no longer damage any electronics.. What do you think?
Anyway I read here about the 330V thing and they are also promoting series filters that don't use MOVs... I wonder if these are gimmicks...
https://www.labmanager.com/laboratory-technology/2014/05/surge-suppression#.W7rOQPZuKh1
"Your computer and laboratory test equipment have semiconductor components such as diodes and transistors that are rated for various voltage/current combinations, but most need to operate below 330 volts. Above 330 volts, pinholes and melt spots occur within the component, which over time leads to failure. This process is analogous to an erosion process that is caused by a small but potent force over time. Again, because a surge is both a rise in voltage and a rise in current, it is important to protect your equipment from both the sudden change in voltage (dV/dt) and current (di/dt)."
<snip>
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Simplified schematic of a series mode filter. There are no sacrificial components, so the filter does not wear down with use, and it repeatedly eliminates surges.Series mode filter technology (real-time suppression)
Another approach is to first consider what a surge really is—a high-frequency noise comprising a rise in voltage and a rise in current that occurs over a period of time. Surges are an unwanted component of the electricity you do want to reach your equipment. Instead of diverting the surge energy, let us consider a method that filters the unwanted surge.
Filtering the surge requires a device that is placed in series with the electric power. Because the filter has to be good enough to limit the voltage rise as well as the inrush of current, there have to be several stages of filtration. The first stage is an inductor coil. A properly designed inductor can choke the higher-frequency noise (i.e., the surge), letting the lower-frequency AC power wave pass through. The second stage is a series of components (mostly capacitors) to keep the voltage to a desired level. By combining these two stages, one could effectively stop the voltage rise and the inrush of current. The surge energy ends up being converted to useful energy and some negligible heat.
Learning from our MOV discussion, we ask about the MCOV and VPR for series mode filters. Do they have the same issues? The answer is no! The VPR for a series mode filter is tested to the lowest 330-volt rating but also has a high MCOV at 175 volts. A series mode filter does not have a joule rating because it does not have a sacrificial component as an MOV does. In fact, a properly designed series mode filter can withstand 1,000 of the worst-case surges (6,000 volts / 3,000 amps) applied in 30-second pulses."
These are supporting a product owned by zero surge company.. here's another message and I wonder if the information is factual.. it said:
Why Whole Building Surge Protectors Don't Work
"Lower VPR Needed
The lower VPR product turns on first, limiting the surge to 400 volts, well below the 700 volt panel protector clamping rating — making the higher VPR "whole building" main panel and branch circuit protectors useless, and the point-of-use protector the actual "first line of defense".
"Whole building" and panel protectors with VPRs of 700 volts or more, are ineffective when the required lower clamping level plug-in protectors are on the same circuit, because the lower clamping level product will clamp first and do all the work! The claim that the "whole building" protector is the first line of defense is incorrect."
Is it correct information? He is supporter of the Zero Surge product... isn't it if two products have VPR of 400v and 700v and have same MCOV of say 150V. They will clamp at same time if voltage goes above 150V? Or is he correct the product with VPR of 400v will clamp first? Clamping is supposed to be when the MOV starts to short.. and isn't it this occurs above the MCOV and not the VPR. Just verifying to be sure we are not being fooled by manufacturers.. One can directly order these series filters from their website and so attractive to us overseas people:
https://zerosurge.com/plug-in-products-solutions/
