EEVblog > News/Suggestions/Help

EMP Shield Scam

<< < (4/4)

opto_isolator:
Thought I'd share what I found:

https://pdfpiw.uspto.gov/.piw?PageNum=0&docid=10742025&IDKey=36E709D42475&HomeUrl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO2%2526Sect2%3DHITOFF%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsearch-bool.html%2526r%3D1%2526f%3DG%2526l%3D50%2526co1%3DAND%2526d%3DPTXT%2526s1%3Dcarty%2526s2%3Demp%2526OS%3Dcarty%252BAND%252Bemp%2526RS%3Dcarty%252BAND%252Bemp

If you look at the diagrams (and descriptions) it appears that all this is, is a collection of surge devices between phases /  neutral / ground.  Most likely it's a collection of TVS diodes, probably something like this:

https://www.mouser.com/ProductDetail/Littelfuse/15KPA120A/?qs=MLCmBfHNlR5528SJT7SrPg%3D%3D

So it's a fairly simple design that uses off the shelf parts.  From what I can tell, it's not supposed to shield your devices in the house from a direct EMP hit, meaning if you are in the danger zone, the field strength will just be everywhere and everything will be hit unless they are in a faraday shield.  I beleive the intent of this is to address only the power feed coming into your house - which would possibly work if the actual EMP would not have much influence of other devices due to proximity, as it would shunt (quickly) any large voltage surge generated by the E1 to ground.  It appears that this device is a combination device to address EMP as well as standard surges genereated by system imbalances and lightning strikes.  Considering they charge what they do for it, they're making a killing compared to parts / assembly cost.

Keyslammer:
So.....I thought I would challenge the vendor on their claims.  Here is the response I received.  Feel free to follow up and post YOUR results.  My favorite part is: "...the rise in voltage has no effect on the electronics".  Since he is welcoming any questions or concerns, I've included the contact information...

Great to hear from you,
Thank you for your interest in our product. An EMP is an RF event, and the fast rising pulse generates destructive voltages inside the electronics. This is a true statement. except for the rise in voltage has no effect on the electronics. Voltage in and of itself is not destructive. Look at a stun gun, the produces 100,000 volts but doesn't kill you because there are no amps behind the voltage. Voltage produces current, current produces amp, and amp produces heat. Heat is what "Fries" everything in the electrical system. This is a process and like any other process, it takes time for this to happen. Granted it happens in microseconds which is fast. This is where the emp shield comes into play. The EMP Shield monitors the voltage in the system as a whole. No matter where the volt in the system comes from the system as a whole will rise and fall at the exact same time. Because of this the EMP Shield only needs to be a part of that system. Because we are looking for the voltage spike, not the amp spike we can get the voltage out of the system faster than it is able to produce the destructive heat. our units are functioning in the 500 trillionths of a second. If the destructive heat is being produced in the microsecond then our unit is able to get rid of this overvoltage faster than its ability to produce that heat.
If you have any other questions or concerns please feel free to give us a call and I would love to address them any way I can.
Respectfully,
Benjamin Fletcher
Senior Sales Manager
3908 S. 4th St
Burlington, Ks 66839
(620)412-9978
bfletcher@empshield.com
empshield.com

Cerebus:
One thing to say about that, that ought to be obvious to "one skilled in the art" to borrow a phrase.


--- Quote from: "Benjamin Fletcher" on September 22, 2021, 05:35:57 pm ---No matter where the volt in the system comes from the system as a whole will rise and fall at the exact same time. Because of this the EMP Shield only needs to be a part of that system.

--- End quote ---

No, no it does not. You can't treat a whole electrical system at sub microsecond magnetic pulse scale as a lumped component. Even if it is just wires they have distributed inductance and capacitance. Clamping at one point does not mean the whole system is clamped.

If any one is interested Schaffner sell pukka mains filters designed to protect adequately shielded equipment from conducted EMP effects.

Of course it's a toss up which is worse, the radiation that will get you a few days after an EMP event, or the stench of RIFA capacitors that will get you in few seconds after an EMP event if you have Schaffner filters fitted.  :)

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version