Re: [PSES] MOV requirements

2011-11-14 Thread Mick Maytum
Fri, 11 Nov 2011, Mick Maytum m.j.may...@ieee.org writes: MOV, Varistor, VDR; Metal-Oxide Varistor are all names for a voltage-limiting component using a particular technology. I think this 'particular technology' is an important point. As I understand it, devices like Transorbs (TM?) are quite

[PSES] SPC component properties

2011-11-15 Thread Mick Maytum
Brian, I appreciate for your purposes the SPC component of choice is the MOV. Quite right too, if you are considering cost and device safety standards like UL 1449. SPC standards, which tend to be for component electrical and environmental performance, can only overlap the requirements

Re: [PSES] AC Powering or not to AC power that is the test option

2011-11-15 Thread Mick Maytum
Brian, I find portions of our discussion has been transcribed to the entire IEC TC 108 group. Thus I feel I should respond to your TC 108 comments A problem NOT ADDRESSED by TC108 is the increased energy AFTER a surge, or during a SFC, due to the 120% rating requirement. Perhaps this was

Re: [PSES] Steady State Conditions - née thermal equilibrium

2012-01-12 Thread Mick Maytum
The IEC offers several definitions of thermal equilibrium in its Glossary. thermal equilibrium conditions stable temperature conditions indicated by temperature changes of no more than 3 K (5 °F) or 1 % of the absolute operating temperature, whichever is higher between two readings 15 min

Re: [PSES] Steady State Conditions - née thermal equilibrium

2012-01-12 Thread Mick Maytum
the data as HTML expressions in an Excel spreadsheet - a frustrating exercise if you were not proficient in HTML. Mick On 12/01/2012 11:24, John Woodgate wrote: In message 4f0eba2a.8070...@ieee.org, dated Thu, 12 Jan 2012, Mick Maytum m.j.may...@ieee.org writes: Nice to see a harmonised

Re: [PSES] Is this common knowledge - Electrical Ratings

2012-01-27 Thread Mick Maytum
Dans experience reminded me of a guy who bought a 120 V coffee maker as a present for someone in (old) England. Having some knowledge of AC supplies he bought a 240 V to 120 V travel adaptor so the coffee maker could operate on UK 240 V mains. Unfortunately the adaptor consisted of a series

Re: [PSES] Hipot with in-circuit voltage limiting devices IEC 61010-1 3rd Ed.

2012-05-09 Thread Mick Maytum
Clamping voltage is the MOV voltage under specified surge conditions. Typically that will be an 8/20 impulse. IEC 61643-331, ed. 1.0 (2003-05) clamping voltage VC peak voltage across the MOV measured under conditions of a specified peak pulse current (IP) and specified waveform Your 1 mA

Re: [PSES] Hipot with in-circuit voltage limiting devices IEC 61010-1 3rd Ed.

2012-05-10 Thread Mick Maytum
Doug, My previous message gave the IEC rulings - terms clamping voltage and nominal varistor voltage - for two specific points on the MOV clamping (clipping) characteristic. For completeness IEC 61010-1, ed. 3.0 (2010-06) defines the following: *working voltage * highest r.m.s. value

Re: [PSES] Hipot with in-circuit voltage limiting devices IEC 61010-1 3rd Ed.

2012-05-10 Thread Mick Maytum
this the 8 mS / 10 mS rating. That's mS, not uS. -- Thanks, -doug Douglas E Powell doug...@gmail.com mailto:doug...@gmail.com http://www.linkedin.com/in/dougp01 On Thu, May 10, 2012 at 6:58 AM, Mick Maytum m.j.may...@ieee.org mailto:m.j.may...@ieee.org wrote: Doug, My

Re: [PSES] 8/20 waveform

2013-05-03 Thread Mick Maytum
Kris, If you pull a copy of Impulse generators for testing low voltage equipment from the IEEE PES Surge Protective Devices Committee (SPDC) Website. http://pes-spdc.org/sites/default/files/Impulse_generatorsaddedrev2.pdf Figure 12 of the document shows the typical 1.2/50-8/20

Re: [PSES] safety 60950 and surge suppression circuits - GDTs

2013-05-12 Thread Mick Maytum
John, It is true that people used to worry about GDTs venting. In venting the GDT sparkover voltage greatly increased. In fact, there was a US trend to include a Back-Up (air) Gap (BUG) across the GDT component in case this happens. In fact, due to contamination, these BUGs were more

Re: [PSES] safety 60950 and surge suppression circuits

2013-05-21 Thread Mick Maytum
Rich, Given your rational that surge protective components (SPCs), such as MOVs or GDTs, can have a fault mode anywhere between a short-circuit and an open-circuit, looks like there is a disconnect in the test levels. In the open-circuit situation, the SPC does not divert current and

Re: [PSES] safety 60950 and surge suppression circuits - 13A plugs

2013-06-18 Thread Mick Maytum
Joe, My memories of the early 13 A plugs in the UK is their consistency rather than inconsistency. I was in TV design at that time. Traditionally the early TV power supplies used a half-wave rectifier, so the chassis was either L or N. When the 13 A plug became widely used the chassis was

Re: [PSES] Crossed-out wheeled bin symbol

2014-09-24 Thread Mick Maytum
Each Annex is terminated by a short horizontal line. The thin line is meant to be there, but it is not part of the symbol. Mick On 24/09/2014 20:31, Brian Oconnell wrote: Am confused over this. Cannot determine if thin line is a PDF 'artifact', or if that is the new image for the EEE mark.

Re: [PSES] Graphic Symbols for Electrical and Electronics Diagrams

2015-01-17 Thread Mick Maytum
David, I am familiar with IEEE Std 315, IEEE Std 315A (supplement) and the IEC 60617 database. The 315 was created in 1975 and the 315A in 1986. These documents show some symbols with an over and under lined IEC label. At the time of creation the IEC reference was to the symbols in

Re: [PSES] Graphic Symbols for Electrical and Electronics Diagrams

2015-01-18 Thread Mick Maytum
the need for the subscription since that's primarily what we need the symbols for anyway. Thanks -Dave -Original Message- From: Mick Maytum [mailto:mjmay...@gmail.com] Sent: Saturday, January 17, 2015 5:26 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Cc: Nyffenegger, Dave Subject: Re: [PSES] Graphic

Re: [PSES] Different surge test equipment, different results

2015-08-22 Thread Mick Maytum
Peter, The metrics we use to specify the more complex surge waveshapes are only a modest improvement over the answer a red one to the what car do you drive? question. The ring and possibly 8/20 (part of the combination) waveshapes have current reversals, which complicates matters.

Re: [PSES] EN 62368-1 query

2015-10-29 Thread Mick Maytum
On 26-Oct-15 6:29 PM, Scott Aldous wrote: _Table 5 (Capacitor Energy)_ For the energy from a capacitor, the table takes into account capacitance and voltage, so both need to be taken into account since the equation for available energy from a capacitor includes both variables. This is

Re: [PSES] EU Certifications Required for Surge Protectors?

2017-04-06 Thread Mick Maytum
. Regards, Mick Maytum -- Original Message -- From: "Brian O'Connell" <oconne...@tamuracorp.com> To: EMC-PSTC@listserv.ieee.org Sent: 06/04/2017 22:00:35 Subject: Re: [PSES] EU Certifications Required for Surge PRotectors? Dunno, as have just used the standards referenced in ann

Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

2017-11-12 Thread Mick Maytum
disconnect, gets to the heart of the matter. But, as far as I'm aware, none of these tests apply a surge voltage to check for open thermal switch arc over. Regards, Mick Maytum Safety and Telecom Standards mjmay...@gmail.com https://ictsp-essays.info

Re: [PSES] Regulatory requirements for MOVs placed line-to-ground on AC mains ports?

2017-10-31 Thread Mick Maytum
, Mick Maytum Safety and Telecom Standards mjmay...@gmail.com www.ictsp-essays.info -- Original Message -- From: "Joe Randolph" <j...@randolph-telecom.com> To: EMC-PSTC@listserv.ieee.org Sent: 31/10/2017 02:09:14 Subject: [PSES] Regulatory requirements for MOVs place

Re: [PSES] IEC 61000-4-5:2014/AMD1:2017 - Using the correct CDN for AC mains testing

2019-04-03 Thread Mick Maytum
ed an interesting test circuit that imposes a common-mode surge on both supply polarities. Any system polarity earthing and the presence of any voltage limiting functions condition the resultant surge on the system to be common-mode, differential mode or a mixture of both. Regards, Mick Maytum

Re: [PSES] classification of the output

2019-03-14 Thread Mick Maytum
://ict-surge-protection-essays.co.uk/ -- Original Message -- From: "Pete Perkins" To: "Mick Maytum" ; EMC-PSTC@listserv.ieee.org Sent: 13/03/2019 06:11:38 Subject: RE: [PSES] classification of the output Mick, Thanx for the reply given on this thread.

Re: [PSES] classification of the output

2019-03-12 Thread Mick Maytum
Joe Randolph and I talked about “pulsed power” delivery at the 2019 ATIS-PEG conference last week and how it should be treated. A good starting point is the IEC 60479 series of documents on “Effects of current on human beings and livestock”. IEC 62368-1 mentions the time locked IEC TS

Re: [PSES] Dated and undated references

2019-04-20 Thread Mick Maytum
t reference for IEC 61643-331:2017 is "from 8.2.2 of IEC 61643-331, Figure 4." Thinking about what John said, it seems to me the quickest way of fixing the IEC 62368-1:2018 reference, without invoking TC 108, would be for SC 37B to issue a clause 8 corrigendum. Regards Mick Ma

Re: [PSES] High voltage versus High tension

2020-08-03 Thread Mick Maytum
The terms are international, not just EU. If you look in the IEC Electropedia terms and definitions there is en high voltage high tension HV voltage having a value above a conventionally adopted limit Note – An example is the set of upper voltage values used in bulk power systems.