GDT internal spacing? not if a gas tight tube.
External terminals for sure, but internal not, because the internal pressure
does not go to altitude.
It remains at the same pressure, unlike parts open to the environment.
BUT, when an agency and their personnel are involved, there is no telling what
Thank you everyone for sending your feedbacks.
Asking any question at the same as "spark gap" question its like releasing your
indie film on the same weekend as "Spider-man"
Limited responses were ranging from "never heard of anyone asking for more than
2000m" to "different" to "2500; 3048, 40
Hi Gert:
Do you know of a source for a small, inexpensive gas tube with a rated
breakdown voltage in the range of 6 KV to 10 KV? I don't, but I'd
like to know of a suitable source.
As I noted, conventional gas tubes are typically rated at a few hundred
volts. Putting a 400 volt gas tube across
Please remove me from your email list.
Thanks,
Kirk
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Hi Brian:
I think it is a good idea to increase the spacings if you have room
available. The statistical relationship between peak surge voltage
and probability of occurrence strongly favors larger spacings.
Doubling the spacings may reduce the probability of breakdown by a factor
of ten.
Regar
In message , dated Fri, 6
Sep 2013, Doug Powell writes:
Best to simply use a glass or ceramic spark gaps which are inorganic
and cannot produce carbon when arced
You are right: using PCB tracks is to invite tracking! A slot in the
board with electrodes on both sides is better. These were
Sheesh, I guess you'll have to cut & paste. Strange...
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Kenneth Wyatt
Wyatt Technical Services LLC
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Phone: (719) 310-5418 / Toll Free: (877) 443-9275
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I'm not a power engineer, but I suspect you'll need something more than
pointed bus bars. A quick search comes up with this:
www.erico.com/public/library/fep/Surge/LT19915.pdf?
Good luck!
Cortland Richmond
On 9/6/2013 1156, Kunde, Brian wrote:
Our engineers are working on an AC Mains Distri
Joe,
Yes we are in agreement, and you make several valid points regarding gas
discharge tubes. As is always the case in any design, there are trade-offs.
I have found it beneficial to use a combination of the very good ideas being
discussed on this thread. For example, solid insulation barr
Hi Doug:
You mention that there are companies that make air gaps. Are these
devices anything like what I described?
What I have in mind is an inexpensive component about the same physical
size and cost as a gas tube, with two tungsten electrodes separated by an
air gap of 5 to 10 mm to achieve
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Thanks,
Mark Tucker
Director of Hardware Engineering
RFM
3079 Premiere Parkway, Suite 140
Duluth GA 30097
mtuc...@murata.com
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CONFIDENTIALITY:
This message contains information which may be confidential and
priv
An air gap is a gas tube without the tube..
And the air properties vary, and so the performance with altitude , humidity
and pollutions.
So just use a commercial available gas discharge tube !
I have seen and recommended ( in that order ;<) mains wire coiled into
a 10 cm coil before
The devices I had in mind were DIN Rail mounted and rated for 6 KV and up. In addition they have built in arc breakers and half cycle surge current ratings of a few thousand amps.For the life of me I cannot recall the company name right now. When I have an opportunity, I will check through my data
PCB gaps (with or without slot) are okay for low-current
discharges. For high-current discharges such as occur
on mains circuits, the current will vaporize the copper
and increase the clearance distance, and thereby increase
the breakdown voltage with each overvoltage event.
Rich
On 9/6/2013
Hi All,
It's been a while since I listed some of the recent blog postings. The EMC Blog
has moved from Test & Measurement World to the EDN.com web after the former was
consolidated as a part of EDN. Hopefully, the older "tmworld" links will
continue to redirect OK. If any of your older links mi
In message
<64D32EE8B9CBDD44963ACB076A5F6ABB02664E67@Mailbox-Tech.lecotech.local>,
dated Fri, 6 Sep 2013, "Kunde, Brian" writes:
I have seen spark-gap lay outs on PC boards on I/O connectors; usually
for ESD protection, but not on AC Mains. Is this a bad bad idea or
something worth doing?
Murphy says it will destroy BOTH boards.
Ed Price
WB6WSN
Chula Vista, CA USA
From: Kunde, Brian [mailto:brian_ku...@lecotc.com]
Sent: Friday, September 06, 2013 10:15 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] Spark Gap PCB Layout on AC Mains
The thought is that a really h
If the PCB material is removed between the spark-gap layout making an air-gap,
does this resolve the carbon tracking problem?
The spark-gap would not be our primary approach to dealing with surge pulses;
but only to better deal with those higher surge pulses than what we design for.
The thought
The power supply PCB’s I see have holes or slots cut in them between the pointy
conductors. The arc occurs across the air gap. This avoids the carbon
tracking on the PCB condition raised below.
Gary T.
From: Doug Powell [mailto:doug...@gmail.com]
Sent: Friday, September 6, 2013 9:33 AM
To: EM
For some reason, the link to the review of the LTspice book split in
half...here's the repaired link:
http://www.eetimes.com/author.asp?section_id6&doc_id19409&piddl_msgid&6530&piddl_msgposted=yes#msg_266530
Sorry about that, Ken
___
Kenneth Wyatt
Wyatt Technical Services LL
Hi Doug:
I think we are in agreement about some of the pitfalls of spark gaps that
are simply added in the copper layout.
Regarding "spark gap" components, the devices you cite (also
known as gas tubes) typically fire at just a few hundred volts.
Adding these to enhance the surge tolerance of an
Brian,
I am personally opposed to such an idea. The first time I saw this was circa
1982 on an electronic security system; designed to tie into the public
telephone network. The manufacturer wanted additional protection above the
outdoor surge protector. The design involved two parallel zig-
Our engineers are working on an AC Mains Distribution PCB. Like most electronic
devices, we have seen the damage caused by lightning strikes. So we are
increasing our creepage and clearance distances as wide as we can and still
meet other requirements.
But no matter what spacing you design to,
I often see spark gaps on the mains side of AC-DC power supplies PCBs. I
consider it a best practice.
Gary Tornquist
Director of Product Safety
Microsoft Corp
From: Kunde, Brian [mailto:brian_ku...@lecotc.com]
Sent: Friday, September 6, 2013 8:56 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES
John,
Thanks for your reply.
Regards,
Scott
On 6/9/13 2:26 AM, "John Woodgate" wrote:
> In message , dated Fri, 6 Sep 2013,
> Scott Xe writes:
>
>> Do you have any idea what the actual products of non-rewirable
>> intermediate adaptors or adaptor plugs mentioned in sub-clause 15.2 of
>> BS
Hi Anthony,
Appreciate your response and findings. That is to say there are built-in
switches in the extension sockets. In the scope, it is stated that:-
Assemblies comprising a plug and one or more portable socket-outlets
connected together by a flexible cord
or cable are not considered to be
It has to be rms or more accurately the rms equivalent of the peak of the
modulation envelope, because that is how the measurement is made (spectrum
analyzer).
Ken Javor
Phone: (256) 650-5261
From: Tesla
Reply-To: Tesla
Date: Fri, 6 Sep 2013 18:18:22 +0800
To:
Subject: [PSES] ISO 11452-4 Bul
We spec an operating altitude to 3000 m (10,000 feet. sometimes 9800 or
9500 ft, depends on who did the math). We have moved most of our power
supplies to 5000 m in the CQC report for the supply in order to allow us to
claim compliance with the safety requirement to 5000 m in China. We have
not inc
Hi, Experts
For the ISO 11452-4 Bulk current injection test method, if the test level is
200mA. this level is RMS value or Peak to Peak value?
Thanks and Regards.
Tesla.
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This message is from the IEEE Product Safety Engineeri
Dear all,
Is anyone familiar with above mentioned standard?
I need information about distances to dead metal enclosure. Standard requires
huge distances from primary live parts to dead metal enclosure but there is no
definition of dead metal enclosure in the standard. Is earthed enclosure
cons
Hello Scott,
I was curious to know myself but I'm not sure I came up with the right answer.
The Terms & Definitions section of BS 1363-3 defines "intermediate adaptor" as
"a fused adaptor having one or more socket-outlets and provision for the
connection of a flexible cord to a remote control d
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