[RE-wrenches] EMP - Faraday Cages

Sun Sep 10 14:53:15 PDT 2017

Interesting but scary subject for me !  I hope we don't find out how 
well they work !

The MidNite SPDs use MOVs  with a rating of  15 nano-second response time.

This response time is in line for type 2 and 3 EMP events but your 
mileage may vary.

Type 1 EMPs (pico-seconds ?) have faster rise and fall times so will 
fall outside those specifications but

might help ?  I don't know.   Up here in the pacific northwest, Boeing 
actually has an

EMP test facility for military aircraft and equipment...  It is very 
expensive to book

time there I am told by my brother Robin, who has submitted equipment to 
in a past

life and work-place.

EMPs are kind of like lightning in that the field strength will vary 
depending on

distance from and strength of the source as well as how much the wires 
connecting your

equipment to the outside world act as antennas....   Like a lightning 
strike, results may just be

luck of the draw, especially if it were to be like a direct hit and 
short rise/fall times.

I would guess that wire length (resonance) may have a  effect on how 
well they act as an antenna for

a given pulse width for lightning or an EMP ?

Faraday cages may not help at all unless they are used for storing spare 
equipment and with NO wires

exiting and entering.  Ferrites connected as common mode filtering (all 
wires passing through) may

or may not help on external wiring either.

If an EMP does occur, I would replace the SPDs with new ones to be safe 
for the next one...

And do not  hesitate to give us a call and tell us how well it worked !  
You might need to leave

a message though as we will probably be very busy at that time.

boB, at SPI in Vegas

On 9/9/2017 4:22 PM, drake.chamberlin at redwoodalliance.org wrote:
> How about using a solid metal enclosure instead of a mesh? Would that 
> cover frequency differences?
>
> One thing railroad tracks and telegraph wires have in common is that 
> they are very long metallic conductors. The charged particles cut 
> across the conductors for extended distances,  That situation would be 
> similar with a grid connected inverter.
>
> If the inverter were isolated from the grid, with the breakers turned 
> off (or removed), maybe that would help, depending on the magnitude of 
> the pulse.
>
> The electronics would  need to be isolated from the grounded, 
> conductive cover of the enclosure. The equipment should be isolated by 
> design with neutral and ground separate.
>
> Would a Midnite surge protector be of any help in an EMP event?
>
> Thanks,
>
> Drake
>
>
>
>
>     ----- Original Message -----
>     From:
>     "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>
>     To:
>     "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>     Cc:
>
>     Sent:
>     Fri, 8 Sep 2017 14:56:37 -0400
>     Subject:
>     Re: [RE-wrenches] EMP - Faraday Cages
>
>
>     Spent a little time over the last few years trying to study this,
>     there is dozens of answers to the same question it seems if you
>     surround it with mesh it depends on the spaces size in the mesh
>     and it also depends on the frequency of the EMP
>
>     I would not bet that just putting a disconnect in the wires would
>     help but lightning is capable of jumping miles across the sky I
>     can't imagine that an emp would be any different I'm sure it could
>     bridge a gap the size of a breaker or disconnect relatively easily.
>
>     During the Carrington event in the 1800s it was setting railroad
>     ties on fire as well as burning down telegraph offices
>
>     I'm afraid the best bet would be a back up inverter and controller
>     properly wrapped and shielded and make the sign of the cross and
>     pray for the best !
>
>     And if it's atmospheric like a solar pulse or other challenge you
>     would want to wait several days before you brought out your back
>     up stuff because you may get hit again in a matter of hours or
>     days and it be a shame to get everything possibly working again
>     and have it wiped out by the 2nd hit
>
>     I'm probably already outside of what Michael would like me to be
>     so we can continue later if you like
>
>     Bob ellison
>
>
>
>     On Sep 8, 2017, at 12:22 PM, drake.chamberlin at redwoodalliance.org
>     <mailto:drake.chamberlin at redwoodalliance.org> wrote:
>
>         In 2013 we were having a discussion of Faraday cages. I don't
>         think we ever got an answer to the question of whether a
>         grounded inverter or charge control enclosure would serve as a
>         Faraday cage? If all external lines were disconnected, would
>         the grounded metal enclosure prevent damage from an EMP?
>
>         Thanks,
>
>         Drake
>
>         Chris Daum
>         <https://www.mail-archive.com/search?l=re-wrenches@lists.re-wrenches.org&q=from:%22Chris+Daum%22>
>         Tue, 07 May 2013 12:21:16 -0700
>         <https://www.mail-archive.com/search?l=re-wrenches@lists.re-wrenches.org&q=date:20130507>
>
>
>         Dear people:
>
>
>
>
>
>
>         So I have a customer worried about the end of the world as we know it.  I've
>
>
>
>
>
>         looked at the HP archives and see comments from a while ago.  Other than
>
>
>
>
>
>         screening/boxing components and adding mucho surge protectors, is there
>
>
>
>
>
>         anything else that can be done that might actually work?
>
>
>
>
>
>
>         Thanks!
>
>
>
>
>
>
>         Chris Daum
>
>
>
>
>
>         Oasis Montana Inc
>
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