Re: Voltage Spikes on Power Lines etc
Regarding the snippet below paralleling the bulk cap with a ceramic addresses differential mode noise such as the vacuum cleaner, but it doesn't help against common mode noise that the cm choke and snap-on ferrite sleeve address. Line to ground or Y-caps will work with the cm choke and snap-on ferrite to attenuate cm spikes. -- >From: John Barnes >To: George Stults , emc-p...@majordomo.ieee.org >Subject: Re: Voltage Spikes on Power Lines etc >Date: Thu, Mar 14, 2002, 5:16 PM > > A very basic precaution is to put ceramic capacitors in parallel with > the bulk electrolytic capacitors in your power supply, to short out the > high-frequency components of the spikes. A common-mode choke on the > input can also help a lot. To see if this would help, you can put a > snap-on ferrite sleeve around the power cord next to the power supply. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
RE: Voltage Spikes on Power Lines etc
One clear piece of evidence is that safety standards committees always specify much larger creepage and clearance distances for externaly supplied hazardous voltages than for those generated within a product. A good example are the two sets of tables in IEC or EN 60 950. This is to accomodate high voltage spikes and lightning induced voltages etc. Bill Ellingford -Original Message- From: George Stults [mailto:george.stu...@watchguard.com] Sent: 14 March 2002 17:17 To: emc-p...@majordomo.ieee.org Subject: Voltage Spikes on Power Lines etc Hi Folks, I am trying right now to convince some folks that power line voltage spike problems can be and usually are severe enough to degrade or kill ITE products that don't have adequate over-voltage protection. I found a link using Google that describes the problems [ http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to specifics or summaries if any one knows of such. Thanks in advance. George S. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" * --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: Voltage Spikes on Power Lines etc
George, I discuss problems with powerline-spikes in chapter 8, Designing Power Supplies, of my bookElectronic System Design: Interference and Noise Control Techniques (Prentice-Hall, 1987, now out of print). For equipment that will be used indoors, you should try to design your equipment to be immune to 6kV spikes. That is approximately the voltage at which our wall outlets arc over. A quick and dirty test is to plug a vacuum cleaner into the same wall outlet as your product, and try to run your product with the vacuum cleaner running. Vacuum cleaners use universal motors, which have the rotor windings connected to the field winding through a commutator. The arcing at the commutator puts a tremendous amount of hash on the powerline, which will sneak through linear or switching power supplies if you aren't careful. One of my first business trips after I got out of college was going to Chemical Bank in New York City, because one of the Sycor 250 terminals (for which I had written the firmware) would lock up every night. The hardware designer and I installed some hardware and software monitors on this unit, and left for the evening. Next morning we returned, and discovered that it had died shortly after 11pm-- the very time that the cleaning people were making their rounds! We discovered that the cleaning people were plugging their industrial vacuum cleaners into the same wall outlet as our terminal because it was convenient. I think that the bank changed to a simplex wall outlet there, and that solved the problem. A very basic precaution is to put ceramic capacitors in parallel with the bulk electrolytic capacitors in your power supply, to short out the high-frequency components of the spikes. A common-mode choke on the input can also help a lot. To see if this would help, you can put a snap-on ferrite sleeve around the power cord next to the power supply. John Barnes dBi Corporation http://www.dbicorporation.com/ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: Voltage Spikes on Power Lines etc
I don't doubt that telephone equipment is sensitive to lightning-induced voltage spikes on power lines, WHEN the earth ground for the telephone line is physically separate from the ac neutral earth ground, as it can be according to older electrical codes (USA). This is the same problem that blows out TVs and VCRs, except there the ground separation is between ac neutral and the cable. The important point is that it isn't the magnitude of the spike alone, but rather a differential potential induced across victim equipment with connections to two different potentials. Modern electrical codes provide single-point grounds which should totally mitigate this type of failure. Finally note that the failure mode here is not differential mode but common mode, spike arrestors if used need to connect between each power feeder, phone or cable line and green wire in order to be effective. -- >From: "Roman, Dan" >To: "'George Stults'" , emc-p...@majordomo.ieee.org >Subject: RE: Voltage Spikes on Power Lines etc >Date: Thu, Mar 14, 2002, 2:04 PM > > > George, > > The ACTA for Part 68 has issued an advisory for Customer Information > documentation for Part 68 devices. It suggests a warning be included > suggesting the use of an AC surge arrestor. This is on page 7 of 8 of a PDF > file downloadable from http://www.part68.org/. > > It claims that telephone companies have reported that electrical surges are > very destructive to customer telephone equipment connected to AC power > sources. It also states that "This has been identified as a major > nationwide problem." > > A source for this information is not provided, but perhaps somewhere on the > web site you might find a contact that could point you to hard data. > > Dan > > -Original Message- > From: George Stults [mailto:george.stu...@watchguard.com] > Sent: Thursday, March 14, 2002 12:17 PM > To: emc-p...@majordomo.ieee.org > Subject: Voltage Spikes on Power Lines etc > > > > > Hi Folks, > > I am trying right now to convince some folks that power line voltage spike > problems can be and usually are severe enough to degrade or kill ITE > products that don't have adequate over-voltage protection. I found a link > using Google that describes the problems [ > http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to > specifics or summaries if any one knows of such. > > Thanks in advance. > > George S. > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: emc-p...@hypercom.com > Dave Heald: davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://ieeepstc.mindcruiser.com/ > Click on "browse" and then "emc-pstc mailing list" > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: emc-p...@hypercom.com > Dave Heald: davehe...@mediaone.net > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > All emc-pstc postings are archived and searchable on the web at: > http://ieeepstc.mindcruiser.com/ > Click on "browse" and then "emc-pstc mailing list" > --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: Voltage Spikes on Power Lines etc
Hi George:
Take a look at IEEE standard C62.41 ('Recommended Practice on Surge Voltages in
Low-Voltage AC Power Circuits'). It has summaries of transient voltage surveys
done by other people around the world.
Other portions of the standard suggest specific types of surge tests & test
levels. These are based on geographic location, as well as location on the
premises (equipment connected deep within a building, connected near the main
circuit breaker box, or connected near the utility power pole.)
Note - it doesn't talk about equipment malfunction, just about the types of
transient voltages recorded.
On Thu, 14 Mar 2002 09:17:29 -0800, George Stults
wrote:
>I am trying right now to convince some folks that power line voltage spike
>problems can be and usually are severe enough to degrade or kill ITE
>products that don't have adequate over-voltage protection. I found a link
>using Google that describes the problems [
>http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to
>specifics or summaries if any one knows of such.
Patrick Lawler
plaw...@west.net
---
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RE: Voltage Spikes on Power Lines etc
George, The ACTA for Part 68 has issued an advisory for Customer Information documentation for Part 68 devices. It suggests a warning be included suggesting the use of an AC surge arrestor. This is on page 7 of 8 of a PDF file downloadable from http://www.part68.org/. It claims that telephone companies have reported that electrical surges are very destructive to customer telephone equipment connected to AC power sources. It also states that "This has been identified as a major nationwide problem." A source for this information is not provided, but perhaps somewhere on the web site you might find a contact that could point you to hard data. Dan -Original Message- From: George Stults [mailto:george.stu...@watchguard.com] Sent: Thursday, March 14, 2002 12:17 PM To: emc-p...@majordomo.ieee.org Subject: Voltage Spikes on Power Lines etc Hi Folks, I am trying right now to convince some folks that power line voltage spike problems can be and usually are severe enough to degrade or kill ITE products that don't have adequate over-voltage protection. I found a link using Google that describes the problems [ http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to specifics or summaries if any one knows of such. Thanks in advance. George S. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Re: Voltage Spikes on Power Lines etc
Hi George, One suggestion I have is to put a line viewer or recording device on an unprotected power circuit to record power disturbance events over a period of time. You should be able to rent these recorders if you need hard evidence. There are also some interesting stories at the Oneac site http://www.oneac.com/. Click on "Real Life Stories" for some interesting reading. Hope this helps. - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: "George Stults" To: Sent: Thursday, March 14, 2002 9:17 AM Subject: Voltage Spikes on Power Lines etc > > > Hi Folks, > > I am trying right now to convince some folks that power line voltage spike > problems can be and usually are severe enough to degrade or kill ITE > products that don't have adequate over-voltage protection. I found a link > using Google that describes the problems [ > http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to > specifics or summaries if any one knows of such. > > Thanks in advance. > > George S. > --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
Voltage Spikes on Power Lines etc
Hi Folks, I am trying right now to convince some folks that power line voltage spike problems can be and usually are severe enough to degrade or kill ITE products that don't have adequate over-voltage protection. I found a link using Google that describes the problems [ http://www.kalglo.com/powrline.htm ] but I'm looking for additional links to specifics or summaries if any one knows of such. Thanks in advance. George S. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
