RE: Line/Neutral to Earth MOVS
Hi Paul, Testing to the Generic Standard EN 50082-1:1997 For surges EN 61000-4-5 AC power ports you only need criteria B Temporary degradation or loss of function of performance, which is self-recoverable. Regards Edward O'Toole Intertek Testing Services -Original Message- From: plaw...@west.net [mailto:plaw...@west.net] Sent: Wednesday, June 14, 2000 12:06 PM To: EMC-PSTC Subject: Re: Line/Neutral to Earth MOVS 1) In some cases, additional EMI filters added between the AC input of the system and the power supply can cause the surge waveform to ring higher, causing the power supply to fail. In one case, I was doing Common-Mode surge testing on a system that had extra EMI filters. The surge voltage that the supply saw at it's input terminals was approximately 2x the applied test voltage! The power supply manufacturer may have done their testing with no additional filtering. 2) Be careful when measuring DC output voltages during Common-Mode testing. Oscilloscope grounding & stray capacity can cause the displayed waveform to look worse than it really is. I float the oscilloscope ground, and wrap the scope lead through a large ferrite core to reduce the stray effects. 3) The power supply manufacturer claimed the unit passed their testing. What was their Performance Criteria: A, B or C? The description for Criteria A states 'Normal performance with the specification limits'. What were the specification limits they used? On Tue, 13 Jun 2000 18:09:11 -0400, e...@itsqs.com wrote: >What I have been hearing from customers is that when they measure the >secondary voltage (3.3VDC,5.0VDC)on the power supply with a scope after the >surge, the voltage drops momentarily thus re-setting the processor. The >power supply w hen tested as a stand alone unit passes EN 61000-4-5 because >it continues to run. > >Usually the client puts the onus on the power supply manufacturer. >Best Regards > >Edward F. O'Toole >Intertek Testing Services > >-Original Message- >From: Rich Nute [mailto:ri...@sdd.hp.com] >Sent: Tuesday, June 13, 2000 4:52 PM >To: rbus...@es.com >Cc: emc-p...@majordomo.ieee.org >Subject: Re: Line/Neutral to Earth MOVS > >Hi Rick: > >> Somewhat related to this discussion is the opportunity I had last week to >> perform surge testing on an off-the-shelf, rack mounted PC. The power supply >> in question was from a reputable manufacturer and had safety, EMC and CE >> markings. The system (power supply) passed the "Heavy Industrial" limits >> when tested line to neutral but the computer would reset when tested L/N to >> ground. My rationale for this anomaly was the lack of a suppression device >> (MOV?) to ground. > >I can take some guesses as to what is happening: > >1) The surge current path within the PC developed an >EMI radiated signal within the PC that initiated a >reset. > >2) The PC was interconnected with other units; the >surge current path divided between the PC's ground >wire and the interconnected units' ground wires. >A voltage developed across the signal ground wires >(because they are smaller diameter and higher >resistance the protective ground wires) which >appeared to be a corrupt data signal. The PC reset. > >(However, I would have expected corrupt data, not a >consistent reset, from this hypthesis.) > >3) Same as 2, but an EMI radiated signal from the >grounding path caused the reset. > >Whether or not the PC has a discrete suppression device, >the surge current MUST return to its source (i.e., >complete the circuit). The suppression device limits >the voltage excursion, and probably actually increases >the current. So, I'm not at all sure that a suppression >device would prevent the reset > >In the absence of a suppression device, the current is >due to the Y capacitors and stray capacitance in the unit. >Initially, the surge current will be high, but then, >through the capacitance, it can decay faster than with a >discrete suppression device. But, the Y-capacitors will >cause a double differentiation and there will be a >negative voltage swing before the surge event is complete. > >A "suppression device" CAN be used to control the current >path through the PC such that the surge current does not >cause a reset. > >By the way, Y capacitors can also set the surge current >path. > > >Best regards, >Rich > > > > > > >--- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >To cancel your subscription, send mail to: > majord...@ieee.org >with the single lin
Re: Line/Neutral to Earth MOVS
1) In some cases, additional EMI filters added between the AC input of the system and the power supply can cause the surge waveform to ring higher, causing the power supply to fail. In one case, I was doing Common-Mode surge testing on a system that had extra EMI filters. The surge voltage that the supply saw at it's input terminals was approximately 2x the applied test voltage! The power supply manufacturer may have done their testing with no additional filtering. 2) Be careful when measuring DC output voltages during Common-Mode testing. Oscilloscope grounding & stray capacity can cause the displayed waveform to look worse than it really is. I float the oscilloscope ground, and wrap the scope lead through a large ferrite core to reduce the stray effects. 3) The power supply manufacturer claimed the unit passed their testing. What was their Performance Criteria: A, B or C? The description for Criteria A states 'Normal performance with the specification limits'. What were the specification limits they used? On Tue, 13 Jun 2000 18:09:11 -0400, e...@itsqs.com wrote: >What I have been hearing from customers is that when they measure the >secondary voltage (3.3VDC,5.0VDC)on the power supply with a scope after the >surge, the voltage drops momentarily thus re-setting the processor. The >power supply when tested as a stand alone unit passes EN 61000-4-5 because >it continues to run. > >Usually the client puts the onus on the power supply manufacturer. >Best Regards > >Edward F. O'Toole >Intertek Testing Services > >-Original Message- >From: Rich Nute [mailto:ri...@sdd.hp.com] >Sent: Tuesday, June 13, 2000 4:52 PM >To: rbus...@es.com >Cc: emc-p...@majordomo.ieee.org >Subject: Re: Line/Neutral to Earth MOVS > >Hi Rick: > >> Somewhat related to this discussion is the opportunity I had last week to >> perform surge testing on an off-the-shelf, rack mounted PC. The power >> supply >> in question was from a reputable manufacturer and had safety, EMC and CE >> markings. The system (power supply) passed the "Heavy Industrial" limits >> when tested line to neutral but the computer would reset when tested L/N to >> ground. My rationale for this anomaly was the lack of a suppression device >> (MOV?) to ground. > >I can take some guesses as to what is happening: > >1) The surge current path within the PC developed an >EMI radiated signal within the PC that initiated a >reset. > >2) The PC was interconnected with other units; the >surge current path divided between the PC's ground >wire and the interconnected units' ground wires. >A voltage developed across the signal ground wires >(because they are smaller diameter and higher >resistance the protective ground wires) which >appeared to be a corrupt data signal. The PC reset. > >(However, I would have expected corrupt data, not a >consistent reset, from this hypthesis.) > >3) Same as 2, but an EMI radiated signal from the >grounding path caused the reset. > >Whether or not the PC has a discrete suppression device, >the surge current MUST return to its source (i.e., >complete the circuit). The suppression device limits >the voltage excursion, and probably actually increases >the current. So, I'm not at all sure that a suppression >device would prevent the reset > >In the absence of a suppression device, the current is >due to the Y capacitors and stray capacitance in the unit. >Initially, the surge current will be high, but then, >through the capacitance, it can decay faster than with a >discrete suppression device. But, the Y-capacitors will >cause a double differentiation and there will be a >negative voltage swing before the surge event is complete. > >A "suppression device" CAN be used to control the current >path through the PC such that the surge current does not >cause a reset. > >By the way, Y capacitors can also set the surge current >path. > > >Best regards, >Rich > > > > > > >--- >This message is from the IEEE EMC Society Product Safety >Technical Committee emc-pstc discussion list. > >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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson:pstc_ad...@garretson.org > >For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > >--- >This message is from the IEEE EMC Society Prod
Re: Line/Neutral to Earth MOVS - CM surge issue
> What I and others have seen is that the Common Mode Choke and Y caps will > act > as a voltage doubler during a common mode surge. > I would see a 2X voltage doubling during the surge event. > I believe the surge builds up a voltage on the Y caps and a big field on the > CMC. > When the surge tops off the CMC field collapses and springs off the Y caps > => doubling of the exposure. > You can simulate this on spice easily. > This puts a very big stress on the isolation barriers with possible arcing > across optos and miss-operation. > It would be so much easier to use MOVs line to ground and limit the surge in > the first place. > The best I have done with out MOVs is about 3KV CM exposure. > Since the new EN61000-6-2 CM limit is 2KV I haven't worried about pushing > this limit. > > Problem with a Gas tube in series with a MOV would be turn on time. > The gas tube is very slow. > My understanding of a gas tube - hot to earth is that once it fires it will > not clear untill zero crossing if at all. > One would have to blow a fuse on the exposure? > If anyone has something better please let me know! > > > QUESTION FOR THE GROUP PLEASE > I understand the issue with line powered user devices and MOVs > leaking/shorting. > What about panel mounted automation equipment for industrial applications. > Does the MOV to ground issue still hold? > > Thanks > > Chris Wells > Senior Design Engineer > Cutler-Hammer > well...@ch.etn.com > > > - Original Message - > From: > To: > Sent: Tuesday, June 13, 2000 4:01 PM > Subject: RE: Line/Neutral to Earth MOVS > > > > > > Somewhat related to this discussion is the opportunity I had last week to > > perform surge testing on an off-the-shelf, rack mounted PC. The power > supply > > in question was from a reputable manufacturer and had safety, EMC and CE > > markings. The system (power supply) passed the "Heavy Industrial" limits > > when tested line to neutral but the computer would reset when tested L/N > to > > ground. My rationale for this anomaly was the lack of a suppression device > > (MOV?) to ground. > > > > Rich's argument makes sense, and apparently most PC supply manufacturers > do > > not provide this protection to ground. Why then would I see this problem > and > > what could I do to correct it? > > > > Rick Busche > > Evans & Sutherland > > . > > -Original Message- > > From: Rich Nute [mailto:ri...@sdd.hp.com] > > Sent: Tuesday, June 13, 2000 1:16 PM > > To: dan.kin...@heapg.com > > Cc: c...@dolby.co.uk; pmerguer...@itl.co.il; > > emc-p...@majordomo.ieee.org > > Subject: Re: Line/Neutral to Earth MOVS > > > > > > > > > > > > > Why do you need the MOVs? Why not just take the L & N > > to ground via a gas > > > tube each? > > > > Indeed! > > > > Why, even, use any suppressors? > > > > Supposedly, there is only insulation from L and N > > to ground (earth). As such, it is easy to achieve > > 5 kV worth of insulation. Without much effort, this > > can go to 10 kV. > > > > 5 kV will easily withstand most mains transients. > > If there is concern for transient suppression above > > this value, simply use an air gap between a pair of > > terminals in the circuit. Use the minimum spacing > > allowed by the safety standard. Make sure the > > terminals are robust and coated with solder. This > > way, there will be little or no degradation when an > > arc occurs. (The solder may melt, but it will re- > > form when it cools.) > > > > We always test mains circuits to breakdown. Most of > > our mains circuits go to >5 kV simply by meeting the > > standards' requirements for spacings and Y-caps. > > Our typical >5 kV breakdowns occur between the terminals > > of the Y-caps (on the back side of the PWB, between the > > Y-cap leads protruding on the back side). > > > > I am often amused by the commercial "surge suppressors" > > offered by computer stores and similar stores. If a > > product meets the various "surge" and safety standards, > > there is no need for such devices. > > > > > > Best regards, > > Rich > > > > > > > > > > --- > > This message is from the IEEE EMC Society Product Safety > > Technical Committee emc-pstc discussion list. > > > > To cancel your subscription, send mail to: > > majord...@ieee.org > > with th
Vedr.: RE: Line/Neutral to Earth MOVS
Sometimes I have seen another reason for the problem of reset caused by surge transients. Inside the power supply is a feed-back signal for control of the output voltages and this signal has to pass a galvanic barrier. An optocoupler with a bad common mode rejection may have been used and therefore the common mode surge transients affects the feed-back signal. In this way the power supply shuts down for a short time. Yours sincerely Viggo Brøndegaard, Project manager DELTA EMC department Venlighedsvej 4, DK-2970 Hørsholm Direct tel. +45 4576 7622 ext. 425 Tel. +45 4586 7722, fax +45 4586 5898 Email: v...@delta.dk www.delta.dk >>> 14-06-00 00:09 >>> Hi Rich: What I have been hearing from customers is that when they measure the secondary voltage (3.3VDC,5.0VDC)on the power supply with a scope after the surge, the voltage drops momentarily thus re-setting the processor. The power supply when tested as a stand alone unit passes EN 61000-4-5 because it continues to run. Usually the client puts the onus on the power supply manufacturer. Best Regards Edward F. O'Toole Intertek Testing Services -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Tuesday, June 13, 2000 4:52 PM To: rbus...@es.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Line/Neutral to Earth MOVS Hi Rick: > Somewhat related to this discussion is the opportunity I had last week to > perform surge testing on an off-the-shelf, rack mounted PC. The power supply > in question was from a reputable manufacturer and had safety, EMC and CE > markings. The system (power supply) passed the "Heavy Industrial" limits > when tested line to neutral but the computer would reset when tested L/N to > ground. My rationale for this anomaly was the lack of a suppression device > (MOV?) to ground. I can take some guesses as to what is happening: 1) The surge current path within the PC developed an EMI radiated signal within the PC that initiated a reset. 2) The PC was interconnected with other units; the surge current path divided between the PC's ground wire and the interconnected units' ground wires. A voltage developed across the signal ground wires (because they are smaller diameter and higher resistance the protective ground wires) which appeared to be a corrupt data signal. The PC reset. (However, I would have expected corrupt data, not a consistent reset, from this hypthesis.) 3) Same as 2, but an EMI radiated signal from the grounding path caused the reset. Whether or not the PC has a discrete suppression device, the surge current MUST return to its source (i.e., complete the circuit). The suppression device limits the voltage excursion, and probably actually increases the current. So, I'm not at all sure that a suppression device would prevent the reset In the absence of a suppression device, the current is due to the Y capacitors and stray capacitance in the unit. Initially, the surge current will be high, but then, through the capacitance, it can decay faster than with a discrete suppression device. But, the Y-capacitors will cause a double differentiation and there will be a negative voltage swing before the surge event is complete. A "suppression device" CAN be used to control the current path through the PC such that the surge current does not cause a reset. By the way, Y capacitors can also set the surge current path. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael
RE: Line/Neutral to Earth MOVS
Hi Rich: What I have been hearing from customers is that when they measure the secondary voltage (3.3VDC,5.0VDC)on the power supply with a scope after the surge, the voltage drops momentarily thus re-setting the processor. The power supply when tested as a stand alone unit passes EN 61000-4-5 because it continues to run. Usually the client puts the onus on the power supply manufacturer. Best Regards Edward F. O'Toole Intertek Testing Services -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Tuesday, June 13, 2000 4:52 PM To: rbus...@es.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Line/Neutral to Earth MOVS Hi Rick: > Somewhat related to this discussion is the opportunity I had last week to > perform surge testing on an off-the-shelf, rack mounted PC. The power supply > in question was from a reputable manufacturer and had safety, EMC and CE > markings. The system (power supply) passed the "Heavy Industrial" limits > when tested line to neutral but the computer would reset when tested L/N to > ground. My rationale for this anomaly was the lack of a suppression device > (MOV?) to ground. I can take some guesses as to what is happening: 1) The surge current path within the PC developed an EMI radiated signal within the PC that initiated a reset. 2) The PC was interconnected with other units; the surge current path divided between the PC's ground wire and the interconnected units' ground wires. A voltage developed across the signal ground wires (because they are smaller diameter and higher resistance the protective ground wires) which appeared to be a corrupt data signal. The PC reset. (However, I would have expected corrupt data, not a consistent reset, from this hypthesis.) 3) Same as 2, but an EMI radiated signal from the grounding path caused the reset. Whether or not the PC has a discrete suppression device, the surge current MUST return to its source (i.e., complete the circuit). The suppression device limits the voltage excursion, and probably actually increases the current. So, I'm not at all sure that a suppression device would prevent the reset In the absence of a suppression device, the current is due to the Y capacitors and stray capacitance in the unit. Initially, the surge current will be high, but then, through the capacitance, it can decay faster than with a discrete suppression device. But, the Y-capacitors will cause a double differentiation and there will be a negative voltage swing before the surge event is complete. A "suppression device" CAN be used to control the current path through the PC such that the surge current does not cause a reset. By the way, Y capacitors can also set the surge current path. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Line/Neutral to Earth MOVS
Hi Rick: > Somewhat related to this discussion is the opportunity I had last week to > perform surge testing on an off-the-shelf, rack mounted PC. The power supply > in question was from a reputable manufacturer and had safety, EMC and CE > markings. The system (power supply) passed the "Heavy Industrial" limits > when tested line to neutral but the computer would reset when tested L/N to > ground. My rationale for this anomaly was the lack of a suppression device > (MOV?) to ground. I can take some guesses as to what is happening: 1) The surge current path within the PC developed an EMI radiated signal within the PC that initiated a reset. 2) The PC was interconnected with other units; the surge current path divided between the PC's ground wire and the interconnected units' ground wires. A voltage developed across the signal ground wires (because they are smaller diameter and higher resistance the protective ground wires) which appeared to be a corrupt data signal. The PC reset. (However, I would have expected corrupt data, not a consistent reset, from this hypthesis.) 3) Same as 2, but an EMI radiated signal from the grounding path caused the reset. Whether or not the PC has a discrete suppression device, the surge current MUST return to its source (i.e., complete the circuit). The suppression device limits the voltage excursion, and probably actually increases the current. So, I'm not at all sure that a suppression device would prevent the reset In the absence of a suppression device, the current is due to the Y capacitors and stray capacitance in the unit. Initially, the surge current will be high, but then, through the capacitance, it can decay faster than with a discrete suppression device. But, the Y-capacitors will cause a double differentiation and there will be a negative voltage swing before the surge event is complete. A "suppression device" CAN be used to control the current path through the PC such that the surge current does not cause a reset. By the way, Y capacitors can also set the surge current path. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Line/Neutral to Earth MOVS
Somewhat related to this discussion is the opportunity I had last week to
perform surge testing on an off-the-shelf, rack mounted PC. The power supply
in question was from a reputable manufacturer and had safety, EMC and CE
markings. The system (power supply) passed the "Heavy Industrial" limits
when tested line to neutral but the computer would reset when tested L/N to
ground. My rationale for this anomaly was the lack of a suppression device
(MOV?) to ground.
Rich's argument makes sense, and apparently most PC supply manufacturers do
not provide this protection to ground. Why then would I see this problem and
what could I do to correct it?
Rick Busche
Evans & Sutherland
.
-Original Message-
From: Rich Nute [mailto:ri...@sdd.hp.com]
Sent: Tuesday, June 13, 2000 1:16 PM
To: dan.kin...@heapg.com
Cc: c...@dolby.co.uk; pmerguer...@itl.co.il;
emc-p...@majordomo.ieee.org
Subject: Re: Line/Neutral to Earth MOVS
> Why do you need the MOVs? Why not just take the L & N
to ground via a gas
> tube each?
Indeed!
Why, even, use any suppressors?
Supposedly, there is only insulation from L and N
to ground (earth). As such, it is easy to achieve
5 kV worth of insulation. Without much effort, this
can go to 10 kV.
5 kV will easily withstand most mains transients.
If there is concern for transient suppression above
this value, simply use an air gap between a pair of
terminals in the circuit. Use the minimum spacing
allowed by the safety standard. Make sure the
terminals are robust and coated with solder. This
way, there will be little or no degradation when an
arc occurs. (The solder may melt, but it will re-
form when it cools.)
We always test mains circuits to breakdown. Most of
our mains circuits go to >5 kV simply by meeting the
standards' requirements for spacings and Y-caps.
Our typical >5 kV breakdowns occur between the terminals
of the Y-caps (on the back side of the PWB, between the
Y-cap leads protruding on the back side).
I am often amused by the commercial "surge suppressors"
offered by computer stores and similar stores. If a
product meets the various "surge" and safety standards,
there is no need for such devices.
Best regards,
Rich
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
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:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson:pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
Re: Line/Neutral to Earth MOVS
> Why do you need the MOVs? Why not just take the L & N to ground via a gas > tube each? Indeed! Why, even, use any suppressors? Supposedly, there is only insulation from L and N to ground (earth). As such, it is easy to achieve 5 kV worth of insulation. Without much effort, this can go to 10 kV. 5 kV will easily withstand most mains transients. If there is concern for transient suppression above this value, simply use an air gap between a pair of terminals in the circuit. Use the minimum spacing allowed by the safety standard. Make sure the terminals are robust and coated with solder. This way, there will be little or no degradation when an arc occurs. (The solder may melt, but it will re- form when it cools.) We always test mains circuits to breakdown. Most of our mains circuits go to >5 kV simply by meeting the standards' requirements for spacings and Y-caps. Our typical >5 kV breakdowns occur between the terminals of the Y-caps (on the back side of the PWB, between the Y-cap leads protruding on the back side). I am often amused by the commercial "surge suppressors" offered by computer stores and similar stores. If a product meets the various "surge" and safety standards, there is no need for such devices. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Line/Neutral to Earth MOVS
Why do you need the MOVs? Why not just take the L & N to ground via a gas tube each? Dan dan.kin...@heapg.com > -Original Message- > From: James, Chris [SMTP:c...@dolby.co.uk] > Sent: Tuesday, June 13, 2000 7:10 AM > To: 'Peter Merguerian'; emc-p...@majordomo.ieee.org > Subject: RE: Line/Neutral to Earth MOVS > > > You can use two MOV's in series between L & N and then take the mid point > to > ground via a gas tube. > > One gas tube manfacturers data attached as pdf. > > Chris > > -Original Message- > From: Peter Merguerian [mailto:pmerguer...@itl.co.il] > Sent: Tuesday, June 13, 2000 11:50 AM > To: emc-p...@majordomo.ieee.org > Subject: Line/Neutral to Earth MOVS > > > > Dear All, > > In Europe MOVs located between line or neutral to earth are not accepted. > Does anyone know the rationale behind this? I believe it has to do with > leakage. > > on the other hand, gas discharge tubes are allowed in Euripe between line > and neutral to earth. Does anyone know some reliable manufacturers for > such > gas discharge tubes? > > Thanks, > Peter Merguerian > Managing Director > Product Testing Division > I.T.L. (Product Testing) Ltd. > Hacharoshet 26, POB 211 > Or Yehuda 60251, Israel > > Tel: 972-3-5339022 Fax: 972-3-5339019 > e-mail: pmerguer...@itl.co.il > website: http://www.itl.co.il > > > > > > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > 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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson:pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > > > > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > 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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson:pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > << File: Sankosha.pdf >> --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Line/Neutral to Earth MOVS
Peter - Depending upon the equipment classification and country for deployment, MOVs can be connected to protective earth. Rather than repeat what is already published, please see the link below for details: http://www.us.tuv.com/news/newslett/nl0598/item6.html If your customer's situation is critical, you may want to consider a review of key target markets for possible immediate deployment, and await re-design for a more complete market entry. Regards, Mark Gill, P.E. EMC/Safety/NEBS Design Nortel Networks - RTP, NC, USA > -Original Message- > From: Peter Merguerian [SMTP:pmerguer...@itl.co.il] > Sent: Tuesday, June 13, 2000 6:50 AM > To: emc-pstc > Subject: Line/Neutral to Earth MOVS > > > Dear All, > > In Europe MOVs located between line or neutral to earth are not accepted. > Does anyone know the rationale behind this? I believe it has to do with > leakage. > > on the other hand, gas discharge tubes are allowed in Euripe between line > and neutral to earth. Does anyone know some reliable manufacturers for > such > gas discharge tubes? > > Thanks, > Peter Merguerian > Managing Director > Product Testing Division > I.T.L. (Product Testing) Ltd. > Hacharoshet 26, POB 211 > Or Yehuda 60251, Israel > > Tel: 972-3-5339022 Fax: 972-3-5339019 > e-mail: pmerguer...@itl.co.il > website: http://www.itl.co.il > > > > > > > --- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > 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: > Jim Bacher: jim_bac...@mail.monarch.com > Michael Garretson:pstc_ad...@garretson.org > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > >
Re: Line/Neutral to Earth MOVS
Peter, You are correct regarding the leakage issue. MOV's will break down after time which may increase the product leakage current. MOV's are allowed to be used from line to earth when placed in series with a gas discharge tube that meets the requirements for basic insulation. I believe there are MOV manufacturers that produce "approved" MOV's, but I don't know if they can be used to bridge basic insulation. Ed From: Peter Merguerian Reply-To: Peter Merguerian To: Subject: Line/Neutral to Earth MOVS Date: Tue, 13 Jun 2000 13:49:34 +0300 Dear All, In Europe MOVs located between line or neutral to earth are not accepted. Does anyone know the rationale behind this? I believe it has to do with leakage. on the other hand, gas discharge tubes are allowed in Euripe between line and neutral to earth. Does anyone know some reliable manufacturers for such gas discharge tubes? Thanks, Peter Merguerian Managing Director Product Testing Division I.T.L. (Product Testing) Ltd. Hacharoshet 26, POB 211 Or Yehuda 60251, Israel Tel: 972-3-5339022 Fax: 972-3-5339019 e-mail: pmerguer...@itl.co.il website: http://www.itl.co.il --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Line/Neutral to Earth MOVS
You can use two MOV's in series between L & N and then take the mid point to
ground via a gas tube.
One gas tube manfacturers data attached as pdf.
Chris
-Original Message-
From: Peter Merguerian [mailto:pmerguer...@itl.co.il]
Sent: Tuesday, June 13, 2000 11:50 AM
To: emc-p...@majordomo.ieee.org
Subject: Line/Neutral to Earth MOVS
Dear All,
In Europe MOVs located between line or neutral to earth are not accepted.
Does anyone know the rationale behind this? I believe it has to do with
leakage.
on the other hand, gas discharge tubes are allowed in Euripe between line
and neutral to earth. Does anyone know some reliable manufacturers for such
gas discharge tubes?
Thanks,
Peter Merguerian
Managing Director
Product Testing Division
I.T.L. (Product Testing) Ltd.
Hacharoshet 26, POB 211
Or Yehuda 60251, Israel
Tel: 972-3-5339022 Fax: 972-3-5339019
e-mail: pmerguer...@itl.co.il
website: http://www.itl.co.il
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
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:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson:pstc_ad...@garretson.org
For policy questions, send mail to:
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