Reverberation Chamber introductory article
Hello all,I have written a short introductory article on reverberation chambers for a local EMC magazine here in Australia.This is enclosed for anybody who has similar interests.Thanks Arun Kaore arun_ka...@yahoo.com - Do You Yahoo!? Yahoo! Auctions - Click and bid on cool stuff like Dave Matthews Band Tickets more! reverbs v1 (2).doc Description: reverbs v1 (2).doc
Fwd: Re: Fwd:information regarding electromagnetic compatibility
Hello, Some sites of interest: www.emcs.org www.emc-journal.co.uk www.ce-mag.com www.dstan.mod.uk www.noblepub.com www.rcic.com www.cix.co.uk You should try testing some vacuum cleaners, washing machines etc to CISPR 14, ITE to CISPR 22, TV equipment to CISPR 13, spark ignited lawn mowers to CISPR 12. Your could try to come and visit us at our lab in St Marys, NSW while we test a lot of commercial and military stuff, apart from development work on reverberation chambers. Unfortunately, we cannot release procedures as they are proprietary. Regards Arun Kaore ADI Limited __ Get Your Private, Free Email 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
FW: broadband narrowband emissions
Hello, I quote MIL STD 462 # 4.2.6: A: The EMI meter shall be tuned over a range of * 2 impulse band widths around the centre frequency of emission. A change in peak detector response of 3 dB or less indicates a broad band emission. A change of greater than 3dB indicates a narrow band emission. B: Measure the PRF of the emission. If the PRF is less than or equal to the impulse BW of EMI receiver it is a broad band emission, if greater it is a narrow band emission. Also practically, the easiest way to determine a NB emission is to drop down or increase the measuring BW 1 or 2 steps in a routine EMI receiver sweep around the emission in a broad span; if the emission remains constant, it is NB emission. Broad band emissions would drop approx 10 dB per step change in the bandwidth. Sweep time could also be varied, time domain BB emissions would change with sweep time; frequency domain NB emissions would more or less remain constant. You have to normalise BB emissions to a 1MHz BW, irrespective of actual measurement BW used. Otherwise, people could shonk a broad band CE03 or RE02 test pass. Computer clocks (and its harmonics) and intentional CW or modulated transmitters generally generate frequency domain NB emission. Commutator motors, thermostats, serial comms links generally generate time domain BB emissions. And finally yes, MIL STD 461D and most commercial standards have got around this NB/BB emission discrimination mess by specifying the measurement BW. Hope this helps. Regards Arun Kaore EMC Engineer ADI Limited Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] mailto:[mailto:ed.pr...@cubic.com] Sent: Friday, 08 October, 1999 4:21 To: 'Muriel Bittencourt de Liz'; Lista de EMC da IEEE Subject:RE: broadband narrowband emissions -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] mailto:[SMTP:mur...@grucad.ufsc.br] Sent: Thursday, October 07, 1999 5:43 AM To: Lista de EMC da IEEE Subject: broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel -- == Muriel Bittencourt de Liz GRUCAD - Group for Conception Analysis of Electromagnetic Devices Santa Catarina Federal University - UFSC PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL Phone: +55.48.331.9649 - Fax: +55.48.234.3790 e-mail: mur...@grucad.ufsc.br mailto:mur...@grucad.ufsc.br ICQ#: 9089332 Alternativa Adreso: mur...@esperanto.nu mailto:mur...@esperanto.nu - Muriel: Narrowband and Broadband are the two extremes of the spectral distribution of a signal's power. The classic NB emission has all of its power contained within a narrow range of the spectrum. Think of a perfect sine wave generator, with no sidebands or frequency instability. But how narrow is narrow? All of the power
FW: Amplifier for measurements above 1GHz
We use Hewlett Packard and Rohde Schwarz pre-amplifiers for CISPR xx class B measurements above 700 MHz, which is when the noise floor starts to bite at the 6dB clearance criterion. We do commercial measurements at mandated test distances only. A 1 m test distance is specified for MIL testing only. A zoomed in measurement from 3m to 1m to beat the noise floor is not recommended as the antenna and EUT dimensions become critical. Hope this helps Regards Arun Kaore EMC Engineer ADI Limited Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: John Cronin [mailto:croni...@hotmail.com] mailto:[mailto:croni...@hotmail.com] Sent: Thursday, 26 August, 1999 7:50 To: emc-p...@ieee.org mailto:emc-p...@ieee.org Subject:Amplifier for measurements above 1GHz I am hoping to purchase a 1 to 5 Ghz amplifier to be used in conjunction with a spectrum analyzer to measure emissions at 3m to FCC requirements. With a 1 MHz bandwidth into a HP microwave analyzer we can only currently measure at 1m. Can we get away with measurements at 1m? Can anyone recommend a low cost microwave amplifier that is suitable for the task? Thanks in anticipation of your response. John Cronin __ Get Your Private, Free Email at http://www.hotmail.com http://www.hotmail.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Equipment Produced in Series
Our interpretation of series produced equipment is that of bulk manufactured units where the CISPR 80-80 rule applies. It could generally be Group 1/2 Class A/B bulk produced lab meters, household/light commercial medical diagnostic gear etc. Equipment not produced in series could imply (say Group 2 Class A) heavy industry items such as massive industrial induction/microwave ovens, billet heaters etc which are unique contract jobs, which will probably never be tested on a test site, but because of the complexities of the installation will be tested in situ. These are the types of jobs where one forgets about the use of LISNs and shudders at the thought of using a HV probe. Cost of such stringent EMC testing will almost inevitably be built into the contract. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: rehel...@mmm.com mailto:rehel...@mmm.com [mailto:rehel...@mmm.com] mailto:[mailto:rehel...@mmm.com] Sent: Tuesday, 24 August, 1999 6:19 To: emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org Subject:Equipment Produced in Series CISPR 11 talks about .equipment produced in series.. Has anyone seen a definition of what equipment produced in series actually means? Is there a time period involved? Does it have to be produced daily, weekly, or monthly? Is a batch of 10 pieces of equipment produced once a year produced in series? Does it have to be made on an assembly line? The reason I ask is that CISPR 11 goes on to say All equipment not produced in series shall be tested on an individual basis. If it is not produced in series then every one made must be tested. What is equipment NOT produced in series? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
ESD/TCF
Leslie Bai wrote: I also would like to share with you my experience when I did a TCF job years ago when I was working in Singapore. We know it is not possible to perform radiated immunity testing at the customer's workshop. It is just simply illegal! But how would you verify the machine's radiated susceptibility? ESD gun can help - think about it. Regards, Leslie Hi Leslie: I am not really sure if an ESD air discharge in situ can form the basis of radiated immunity verification towards a more formal document like a TCF. Radiated immunity tests are performed with a defined modulation (AM or FM) with a 1kHz tone in anechoics. I would have taken the approach of applying the IEC 1000-4-6 or my favourite CS 114 (Bulk Current Loom Injection to 400MHz), noting that predominant EUT susceptibility occurs via cables. This way I would at least ensure that the cables are not susceptible. Such procedures would be more in harmony with a legal document like a TCF, because provisions for in situ testing are made. I would also check the emission profile of the box w/o the cables and ensure this it is below the limits. Because, if an EUT emits spurious emissions at a particular frequency, there is a possibility that it would also be susceptible. Lastly, if I did want to verify the transient broadband response of the EUT, instead of air discharge (which is a no-go), I would have attached the recommended radiated coupling loop in front of the Keytek or Schaffner ESD gun to optimise coupling, being near field. I would still not include the results of these findings in a TCF (being a legal document), primarily because this is pre-compliance work and is not in any way related to mandated standards which have been voted upon as acceptable test/verification procedures. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
ESD
Leslie Bai wrote: ESD test is to verify the EUT immunity due to induced current (nonsense!). The current can be induced by conducted coupling (direct contact) or/and radiated coupling. My understanding of the test is that for contact discharge, conduct coupling is dominate and for air-discharge, radiated coupling is dominate. Thus for contactt discharge, if you can pass the higher level, you may not have much problem with lower levels, but although radiated coupling is not dominate for contact discharge, the effects have to be verified through testing. For air-discharge, ESD test is to verify the effects of electromagnetic field on the EUT - i.e. a kind of field immunity test. Different levels will have a different field distribution around the EUT due to the different dV/dt - Maxwell told us. Thus, the induced current is (mainly) generated by the electromagnetic field. I tested one Fire Alarm system years ago. This system has 128 ports all connected with (at least 5m) twisted wires. I noticed that the cable layout can affect result (pass or fail) significantly when doing air-discharge. However, there is no noticable difference by varying cable layout when doing contact discharge. That was my understanding comes from. Rgds, Leslie Leslie: I differ from this theory of radiated coupling in air discharges. There will be air discharge if the creepage/clearance is less (than say 7mm for 8kV) such that the disturbance voltage just arcs over, if there is a path. The discharge current flows then via the shortest path, corrupting everything in the way, if it is not immune. We note that the Immunity noise threshold for most ICs is less than a couple of volts. The easiest way we employ to fix air discharge problems is by artificially increasing the creepage by adding plastic foil or increasing spacing. Schaffner has different probes, loop types, which are more suited for radiative coupling (near field types) as you suggest, but we use them for pre-compliance purposes only. These are the truly radiative coupling types. They are a poor man's friend for MIL STD 461/462 CS06 (in air!!), or CS115/CS116/ RS02 pre compliance. I cannot comment on your Fire Alarm system though, but I would hazard a guess and attribute it to HCP or capacitive coupling via unshielded cables spaced off the metal test sheet (the GRP). Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: PC Power Supply w/ PFC
Apparently these power supplies are hard to find. I may be slightly off the track here but we designed some a couple of years ago (up to 1000 Watts) using Microlinear Power Factor Regulator Chip ML 4812. It featured a boost buck configuration. We got efficiencies of up to 88 % using powdered iron (not ferrite chokes) material (we had 5% loss in boost and 5% lost in buck). The boost segment corrects the power factor in that it forces the ac line current to track the supply voltage. The buck section is your normal regulator. Our power factor was almost 1 and THD was down to less than 2%. But, they were mainly intended for bulk fluorescent lighting application where the PFC/THD requirements are very stringent. In the lighting industry you couldn't sell something with a THD of say 90% and a Power Factor of 0.3 (I mean the plain Rectifier/ Electrolytic Capacitor/ Switching regulator types). And we did not have to do any fancy design, just followed the Application Note at the back of the Catalogue. Thermals were a bit of a problem though. Microlinear have (and this goes back to 1992) some prototyping kits too. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: John Radomski [SMTP:john_radom...@inter-tel.com] mailto:[SMTP:john_radom...@inter-tel.com] Sent: Tuesday, August 17, 1999 12:34 PM To: emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org Subject:PC Power Supply w/ PFC We are looking for a supplier of 300 Watt PS2, PC power supplies that have PFC (Power Correction Factor). Here is the spec: It must comply with: EN 60950 (safety approval required), EN 50082-1, EN 61000-3-2/3, CISPR 22 (or EN 55022). REQUIRED RATED INPUT: 220-240VAC, 50-60Hz, 3.5A (auto ranging power supplies with input ratings from 100VAC, are accepted) OUTPUT: +5VDC 30A; -5VDC 0.5A; +12VDC 12A; -12VDC 0.5A John Radomski Compliance Engineer Inter-Tel Integrated Systems, Chandler, Arizona, USA john_radom...@inter-tel.com mailto:john_radom...@inter-tel.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: cost effective EMC facility
IMHO, there is no cost effective EMC facility, but you don't have to spend all your bucks all in the one day. A sound and well managed EMC business growth program could see you through. Start off with pre compliance and eventually branch off into formal compliance (by drafting up a Quality System to ISO 25 or whatever, a few test procedures and a few Quality and third party Technical Audits) Buy a 2nd hand shielded room today with a view to lining it with ferrite tiles and/or RAM material such that you meet the Radiated Immunity 16 point check for immunity and alternative sites 3 m NSA for emissions. Initial RE prescans could be done here. Buy a 26 GHz cheap ($25000/-!!) analyser (without preselector) driven by software for now and then go for a $10/- preselectable receiver suitable for formal CISPR measurements and also MIL 462 related work. Start off with a chicken wire mesh car park OATS and improve later; not much hope in Singapore because of the ambients, but you could always go to Malaysia or setup a Sea Plane or a salt water based site (you will get very good NSA, probably won't need NSA). Lastly, performing ESD, EFT and Surge tests in a shielded room/ anechoic chamber will make you very popular among your colleagues because of the additional filtering within the shielded room. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: Qu Pingyu [SMTP:pin...@ime.org.sg] mailto:[SMTP:pin...@ime.org.sg] Sent: Friday, 30 July, 1999 18:38 To: 'emc' Subject:cost effective EMC facility Hello, everyone: I posted an question several weeks ago asking about GTEM. Thanks those who share with me your experience. I may not address my problem very clearly thus I would like to come back to you one more time. We are a R D orgnization in Singapore mainly dealing with semiconductor industry. Since there are some requirements from our industry partners in the area of EMC design, we are considering setting up some EMC measurement capabilities. At the intial stage, we will only consider equipment for radiated emission/susceptibility testing. Our objective is to evaluate the EMC performance of the product from our customers, being of PCB level or system level. Based on those results, we can help our customers to improve their product EMC design so that their product can pass the final compliance testing. The EUT could be small, such as integrated circuits on PCB, but it can also be large such as a PC. Due to our budget constraint, I think GTEM maybe a good choice. Do you guys agree ? If not, any other suggestions ? Thanks in advance. Best Regards Qu Pingyu - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Reliability MIL HDBK 217
Hello all I am overwhelmed with the help I got from you all, this short note is to express my thanks !! Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RELIABILITY TO MIL-HDBK-217
Hi all, Could someone guide me on where to down load from the net or purchase the latest version of MIL-HDBK-217 and approximately how much it would cost. It is a Reliability/MTBF related issue. Thanks in advance. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Root Causes of NSA non-compliance
Richard, Regarding the non uniformities (rippling) on the ground mesh, the detailed equation is given in the ANSI C63. Manual (at the back) dealing with Site Attenuation, this manual tends more towards the optical Rayleigh Criterion. I do not think that this will be a problem at frequencies such as 30MHz (10 metre wavelength; take lambda/10 = 1 metre (CISPR 11 clause 8.1); Site imperfections will really show up at higher frequencies. If the NSA improves at 10 metres, it points more to Mutual Impedance effects. Your list couldn't be more comprehensive, I intend to stick it on our hut at the OATS; the only thing I can add is temperature stability and a calm day, so that between the Vdirect and V antenna measurement at a particular frequency you don't see 4 seasons. Other factors could be antenna impedance and VSWR changes with height; Balun VSWR and losses (deterioration) And really, at the end of the day, just because the site attenuation of any site is accurate, this does not mean that the measurement uncertainity has come down or that the EMC tests that are carried out on the site are equally accurate (nothing to do with the lab or personnel!!) . Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] mailto:[SMTP:wo...@sensormatic.com] Sent: Friday, 23 July, 1999 1:51 To: 'emc-pstc' Subject:Root Causes of NSA non-compliance I can think of the following items that must be investigated if an OATS is not vertically NSA compliant. Can you think of others? Antennas and Cables * Antenna factors * Balance * Currents on transmit cable * Cable proximity to antenna * Dipole length * Bent elements * Mutual coupling factors (at 3m only) * Antenna spacing * Antenna height * Antenna variation from vertical orientation Receiver with tracking generator * Calibration * Internal attenuator scale tolerance * Drift Pad * Size of ground screen * Bonding of screen seams * Earthing of screen around edges * Flatness * RF conductivity from table to screen * Height above surrounding terrain Site * Reflecting objects within ellipse * Reflecting objects outside ellipse * Conductivity of surrounding earth Human Factors * Procedure * Readings * Calculations - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: CISPR 22 / EN 55022
EMC Regulations, standards and specs (particularly CISPR) relating to commercial electronic equipment are aimed at controlling the pollution electromagnetic spectrum and protecting radio communications against radiated and conducted(MAINS PORT) spurious emissions . In particular, CISPR 22 addresses the emissions limits at Mains Port in Table 1 and 2 of clause 5.1. Mains relates to a public utility supplying generally AC power, the corruption of which would create a havoc particularly with AM reception, possible Aircraft/.Airport comms and remote toys operating at 27 MHz. Historically, in the civil sector, the parameters of the LISN were determined by analysing the RF impedance of domestic, Industrial and other mains supply systems. The mean values were found to be well represented by an equivalent circuit of 50 ohm in parallel with 50uH. Since good agreement was possible between several countries this LISN network was adopted by CISPR in publication 16 as being suitable for AC supply. CISPR 14 treats DC ports as additional terminals, with the relaxed limits of Table 1 and recommends the use of a HV Probe (where a LISN cannot be used). So, the measurement and limits of DC Ports have been specified in a CISPR publication, which could at least provide a guideline and be consistent with the general CISPR philosophy. You could always use a HV Probe with the tighter Class B limits, but at the end of the day (and noting your commercial environment and not domestic) economic realities would prevail and perhaps you would opt for the more lenient Additional terminals limits of CISPR 14. We note that DC Port measurements have not been mandated in any CISPR 22 publication. In the interim period and if required by the client, I would tend to go this way. Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: VENTER, Francois [SMTP:fven...@alcatel.altech.co.za] mailto:[SMTP:fven...@alcatel.altech.co.za] Sent: Tuesday, 20 July, 1999 15:44 To: emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org Subject:CISPR 22 / EN 55022 Hi All Due to local demand for the test, we have started to conduct conducted emission tests on dc supply lines to the equipment. The reason why it is demanded is that in a telecoms centre one does not have the equipment connected to a dc battery. It is most of the time connected in parallel with other equipment to a vast dc network. This test is of course not a requirement in CISPR 22 or EN 55022. My question relates to the limit lines in CISPR 22/EN 55022. Would you say that it is valid to apply the limits in the standard to a conducted emission test on a dc line. I currently use the same test procedure and LISN for both ac and dc tests - Rhode Schwarz (Receiver) Scwarchbeck (LISN). I get very repeatable results. Your comments would be appreciated. Yours faithfully FA Venter (PR. Eng.) Alcatel Altech Telecoms Senior Development Engineer - EMC fven...@alcatel.altech.co.za mailto:fven...@alcatel.altech.co.za PO Box 286, Boksburg, 1460, South Africa Tel +2711 899-6658 Fax +2711 899-6590 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: NSA
If the problem is on the horizontals, I hope that you have accounted for the Mutual Impedance Correction Factors of Table G4 (CISPR 16-1:1993). Also, check and make sure that your 3 metre antenna factors are ok, no VSWR problems (put a 3 dB pad to check). Do also make sure that there is no ambient sitting on 30MHz. If possible, shift the frequency marginally (just to get rid of the standing wave null/peak or standing wave, if any- the idea being to catch the Peak value of the direct and reflected rays) and repeat the test. I would also prefer to use two identical tuned dipole antennae for the test, and not broadband. The way I look at it is, if it was ok for 5 years, it points more to deterioration. Although, I am sure that you have done all this. In my personal opinion (and it is mine only!!), I am against performing the mandated 10 metre tests at say 3 metres or whatever, because of erroneous 3/10 metre correlation particularly in the 30 to (say) 80MHz region due to near field effects ( the 2(D exp 2)/lambda) effect. The correlation is fairly bad if the EUT is large, with dimensions approaching test frequency. If there are any ambient conflicts, I prefer zooming in at a reduced bandwidth (lower than 120kHz, for better resolution) if necessary. Why don't you repeat your 30MHz NSA at 10 metres? Regards Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] mailto:[SMTP:wo...@sensormatic.com] Sent: Saturday, 17 July, 1999 3:54 To: 'emc-pstc' Subject:NSA Argh! For the first time in five years, our NSA is out of spec on our 3 meter OATS at 30 MHz. The problem appears to be the turn table. We can move the equipment off of the table to one side or toward the front and comply, so it does not appear to be an off site reflection problem. We have replaced marginal brushes from the table to the ring and we have added wide copper ground strips from the ring (attached with screws) to the ground screen (soldered). Still won't pass. Suggestions? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Computer Monitor Magnetic Immunity
General Immunity thresholds for computer monitors: 30-450Hz: Approx. 160-170 dBpT 450Hz-15kHz: 100 dBpT I have generally seen good immunity at frequencies in excess of 15kHz. Tests performed with MIL-461C RS01 loop/audio oscillater+audio amplifier. Monitor most sensitive when disturbance is applied 5 cm away from the outer shell near the yoke coil. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: ed.pr...@cubic.com mailto:ed.pr...@cubic.com [SMTP:ed.pr...@cubic.com] mailto:[SMTP:ed.pr...@cubic.com] Sent: Tuesday, 13 July, 1999 11:03 To: EMC-PSTC Subject:Computer Monitor Magnetic Immunity Hi Listmembers! Does anyone have an estimate of the magnetic field immunity levels of recent production computer monitors? What levels, in Gauss or Tesla, do monitors actually start to show disturbance? And at what levels could you expect a typical monitor to be not just annoying, but virtually useless? Thanks, Ed -- Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 07/12/1999 Time: 17:03:14 Military Avionics EMC Services Our Specialty Also Environmental / Metrology / Reliability -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: EFFECT
Interesting to note that the term Electromagnetic Effect could be triggered by Enrico Fermi back in the 40's when he suggested that electromagnetic effects would be observed in a nuclear explosion ( with different generation mechanisms- Surface Burst, Air Burst, HEMP etc and different waveshapes and levels) and lightning strikes. Towards achieving better Electromagnetic Compatibility, this resulted in the introduction of MIL 462 tests CS10, CS 11, CS 12, CS 13 and RS05- with most waveforms simulated by the commonly available Solar Transient Generators in shielded rooms and/or Bounded wave TEM cells. In a narrow sense therefore, it could be said that to achieve good compatibility, the equipment should withstand external natural or man made electromagnetic effects. Another form of environmental effect on EMC is the deterioration of EMC gaskets, beryllium fingers and formation of oxides on an otherwise perfect bond in salty, humid or corrosive atmosphere rendering shielding effectiveness failure over time and/or environment, bringing up issues of periodic EMI/EMC Preventive Maintainence in the log books! Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au -Original Message- From: Javor, Ken [SMTP:ken.ja...@hsv.sverdrup.com] mailto:[SMTP:ken.ja...@hsv.sverdrup.com] Sent: Wednesday, 30 June, 1999 1:48 To: 'ed.pr...@cubic.com'; EMC-PSTC; PETER PHILLIPS Subject:RE: EFFECT I agree with the substance of Ed's comment. In my experience the more usual terminology is EME = electromagnetic environment, while E3 (E-cubed) = electromagnetic environmental effects. Neither of these terms relates directly to the adverse effect on rf or EMC performance due to other environmental conditions. -Original Message- From: ed.pr...@cubic.com mailto:ed.pr...@cubic.com [SMTP:ed.pr...@cubic.com] mailto:[SMTP:ed.pr...@cubic.com] Sent: Monday, June 28, 1999 11:43 AM To: EMC-PSTC; PETER PHILLIPS Subject: Re: EFFECT Peter: Electromagnetic Effects (EME) is a bit more comprehensive a concept than Electromagnetic Compatibility (EMC). There are many things that you can do with electromagnetic energy that are not necessarily related to compatibility. RF techniques can be used to investigate or change physical properties, protect friendly forces, confuse hostile forces, deny use of assets, eavesdrop; well, lot's more. I would say that EMC is a subset of EME. Regards, Ed From: PETER PHILLIPS peter.phill...@mira.co.uk mailto:peter.phill...@mira.co.uk Subject:EFFECT Date: Mon, 28 Jun 1999 14:41:12 +0100 To: Emc-Pstc (E-mail) emc-p...@ieee.org mailto:emc-p...@ieee.org Dear group, Has anybody heard about the term EFFECT relating to EMC and environmental testing combined. I am looking for any information on the topic, also any views that people may have regarding the change in EMC performance due to adverse environmental conditions Looking forward to your comments Peter Peter Phillips MIRA (Motor Industry Research Association) Tel:++44 (0)1203 355576 Fax:++44 (0)1203 355486 e-mail peter.phill...@mira.co.uk mailto:peter.phill...@mira.co.uk ---End of Original Message- -- Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 Date: 06/28/1999 Time: 08:42:51 Military Avionics EMC Services Our Specialty Also Environmental / Metrology / Reliability -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: EFFECT
Peter, Noting that the thread has originated from MIRA, some of the Environmental Effects which should have minimal EMC impact (over the periodic maintenance lifetime) on the Engine Management Systems, Braking and Air Bag Deployment Systems etc could be: Vibration and Shock, Climate, Temperature, Presence of 60/50Hz High HV Power Cabling and Traffic Management cabling under/over roads etc. There have been incidences of Brakes or other unintended functions deploying with a mind of their own at certain geographic locations and traffic lights! Immunity aspects mostly covered under the Automotive Directive. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au From: PETER PHILLIPS [mailto:peter.phill...@mira.co.uk] mailto:[mailto:peter.phill...@mira.co.uk] Sent: Monday, June 28, 1999 9:41 AM To: Emc-Pstc (E-mail) Subject:EFFECT Dear group, Has anybody heard about the term EFFECT relating to EMC and environmental testing combined. I am looking for any information on the topic, also any views that people may have regarding the change in EMC performance due to adverse environmental conditions Looking forward to your comments Peter Peter Phillips MIRA (Motor Industry Research Association) Tel:++44 (0)1203 355576 Fax:++44 (0)1203 355486 e-mail peter.phill...@mira.co.uk mailto:peter.phill...@mira.co.uk - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org mailto:majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com mailto:ed.pr...@cubic.com , jim_bac...@monarch.com mailto:jim_bac...@monarch.com , ri...@sdd.hp.com mailto:ri...@sdd.hp.com , or roger.volgst...@compaq.com mailto:roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Capacitor Failure Analysis
I have generally seen that if you go by the Ecap data sheet say: 2000hrs @ 105 degrees C. T Then if you are running at an Ecap case temp of say 65 degrees C; the MTBF works out to be about 32000hrs; if the case temp is 75 deg C, the MTBF is 16000hrs and so on. MTBF generally applies to 50% of the batch. Caps generally fail as the electrolyte liquid evaporates due to heat, reducing the ripple current capacity and thus going in to an avalanche deterioration mode inverse exponentially. I would recommend you to run a statistical batch in a temperature controlled oven at about the data sheet temperature, for which the manufacturer has provided the life data. ( Also known as accelerated life test). Related info in MIL-STD-105. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] mailto:[SMTP:wo...@sensormatic.com] Sent: Thursday, 24 June, 1999 5:30 To: 'emc-pstc' Subject:Capacitor Failure Analysis Can you recommend a lab in the USA that can perform failure analysis on an electrolytic capacitor? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Fully Anechoic Chambers (was NEAR/ FAR FIELD CORRELATION ISSU ES)
Mark, In context with the boresighting issues, I think that you are probably referring to the hemispherical arc (with a rotating centre table), which is generally used to model ship borne HF antennae. The other technique could be to boresight the antenna (with a pneumatic cylinder) once the turntable and the mast have been peaked. However, while testing EPIRBS (locator beacons) to COSPAS/SARSAT Type Approval Standard C/S T.007 Issue 3 December 1992 I came upon a fairly interesting math derivation. Such tests are normally performed at 406 MHz with the pristine DIPOLE Antenna (and not the general broadband stuff). Depending on the mast height, the horizontal emissions would generally remain ok, but the verticals could get really crook by as high as 6 dB. Hence for the VERTICAL emissions they propose a: Corrected Antenna Factor AFC = AF (nominal, the 10 metre factor) corrected by a factor P. P= (COS (90*SIN (THETA)))/COS(THETA) THETA= INV TAN (ANTENNA ELEVATION OFF THE TURN TABLE/TEST DISTANCE) Thus, at least mathematically, if not practically (because broadband antennae are generally used in commercial measurements), your measurement uncertainity comes down due to better mathematical boresighting and you get a better vertical result. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au -Original Message- From: Mark Darula [SMTP:mdar...@ckc.com] mailto:[SMTP:mdar...@ckc.com] Sent: Wednesday, 23 June, 1999 11:45 To: emc-p...@majordomo.ieee.org; mailto:emc-p...@majordomo.ieee.org; Roman, Dan; Hans Mellberg Cc: CKC - Clark Vitek Subject:RE: Fully Anechoic Chambers (was NEAR/ FAR FIELD CORRELATION ISSUES) I agree that this is a problem, but one that is unfortunately not improved much (if at all) by the OATS scan height at a 3m distance. This is why CKC proposes above 1 GHz (not 500 MHz) to use a scan arc over the top of the EUT at 1m distance in free space. (a hemisphere type scan, not a straight vertical scan). The problem on an OATS at 3m distance is that the distance (hypotenuse) from the EUT in the 1m - 4m scan increases from 3m to 4.24m at the top of the scan mast. At the same time the directional characteristics (beamwidth) of the antennas typically used (horns) above 1 GHz are narrowing. Due to the increasing distance as the antenna is raised, an EUT would need 3 dB E-field directional gain just to maintain the same signal level as the antenna is raised. Still more gain is needed to overcome any off center beamwidth attenuation of the antennas used, which can easily be 10 - 15 dB above a few GHz. In my estimation, a straight vertical scan of the antenna that does not maintain a boresight on the emissions source or account for the changing test distance as the antenna is raised seems equally if not more unlikely to capture any increased upward emissions from the EUT as a fixed height measurement boresight on the EUT since the amount of EUT gain required to overcome the effects mentioned is more than many antenna designers could hope for at these frequencies. Our principal argument for using the fixed height free space methods in the 30 MHZ - 1 GHZ range is that they provide greater convenience at equal to lower uncertainty than the OATS and therefore should be acceptable. We have verified this claim by three separate methods as have others. Above 1 GHz, I believe that improved methods, such as a scan arc or rotation of the EUT (as in ETS testing)is necessary. Since there are no commercial ITE standards yet above 1 GHZ (besides ETS which are all free space), I believe this presents an excellent opportunity to get it right when 1 GHz methods are incorporated into the ITE standards. Sent by Mark Darula on behalf of Clark Vitek EMC Staff Engineer CKC Laboratories, Inc. -Original Message- From: owner-emc-p...@majordomo.ieee.org mailto:owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] mailto:[mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Hans Mellberg Sent: Saturday, June 19, 1999 7:10 AM To: Roman, Dan; 'emc-p...@majordomo.ieee.org' Subject:Fully Anechoic Chambers (was NEAR/ FAR FIELD CORRELATION ISSUES) The single most biggest problem with a fully anechoic chamber with fixed antenna height as proposed by various groups, is, the inability to detect directed beam emissions especially at higher frequencies (over 500 MHz) Such emissions are, for example, emissions out of drive bays from computers. Most EMC engineers have seen those GHz harmonic emission when processors of 400MHz and higher are used. === Best Regards Hans Mellberg EMC Consultant _ - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org
EN 55024
As I understand it, this is the Light Industrial category. Does EN55024 (or any other ITE standard) also replace EN50082-2 Heavy Industrial? To Jeff and everyone concerned: EN55024 covers only ITE and, as such, it is not intended to replace EN50082-1 for other relevant categories of products. For use of Mission or Process Critical ITE in heavy industrial environment, it would be a commercial advantage for the manufacturers' to still go with the Generic Heavy Industrial EN 50082-2 because of higher levels of applied immunity stress levels (keeping pace with what would generally be expected in the industry) notwithstanding what EN55024 stipulates. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys, NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Clearances
Apply a spray-on type high temperature, high vibration withstand, high breakdown voltage insulation barrier on the motor coil or on the inside of the enclosure if at all feasible. I am not totally clear on your intended application to comment on the MOVS; but generally, MOVs should not be the premier line of defence against voltage stress breakdowns when reduced creepages/ clearances are delibrately designed in. Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys, NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au I developing BLDC (Brushless DC) motor, which is operated 310VDC by IGBT inverter circuit. According to UL standard 1004, motor has clearance 6.4mm between motor coil and metal enclosure at over 300V. In my experience the most important factor of clearance is transient voltage so I think if I use surge suppressor or varistor than can reduce clearance between that parts. Is it right? Does anyone have some good idea about how can reduce clearance. And If it is possible how can I select surge portection? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: NEAR/ FAR FIELD CORRELATION ISSUES
Hi, all You are absolutely right about correlation issues at 3 m/10 m, which arise predominantly from near field effects/ mutual coupling which is best demarcated from the far field by the equation 2*D*exp 2/lambada. Depending on the size of the object under test, the 3/10 m correlation, particularly in the frequency range say 30-100MHz could be out by as much as 5-6 dB (Remember the Mutual Impedance Correction Factors in Table G4 of CISPR 16-1, they were supposed to fix Site Attenuation defects at 3 metres !!). A baseline with some of the less complex artifacts would provide some assistance. Pauls Cook is right in saying that both E and H fields ought to be measured and mutual coupling effects between loop and object under test be accounted.(ie. the effect of the measurement transducer on the EUT) I have recently been quite puzzled by CISPR 11: 1992, when they quoted that below 30MHz the quasi-peak limits refer to the magnetic component of electromagnetic radiation. Contrary to this the limits are specified in dBuV/m instead of dBuA/m (Group 2 Class A, Table 5)!! Now, Because of the frequencies, test object sizes and test distance lengths involved I cannot invoke the golden 120*pi rule and make the conversion. But, is this what is expected of a test house? Also, ITE frequencies have shot past 500MHz, is an equivalent CISPR 22 frequency upgrade in the pipeline? Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys, NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au -Original Message- From: Douglas McKean [SMTP:dmck...@corp.auspex.com] Sent: Friday, 18 June, 1999 6:40 To: emc-p...@majordomo.ieee.org Subject: Re: NEAR/ FAR FIELD CORRELATION ISSUES At 11:18 AM 6/17/99 +1000, you wrote: Even now, correlation between 3 meters and 10 meters is not guaranteed. And further, 3 meter to 10 meter correlation is at least better (define better anyway you wish) in the horizontal. Vertically it's terrible (define terrible anyway you wish). At least in my experience. And a product could be analyzed as being constructed of a variety of antennas - slots, corner reflectors, tuned cavity, tuned arrays, and either electric or magnetic dipoles ... each reacting it's own way in the far field. Now I'm not going to say it's impossible, but it seems to me that one must assume something to begin with instead of being able to blindly take a surface current measurement or near field measurement of X and state confidently that it WILL be Y in the far field under all circumstances. That's ultimately what one would have to be able to do without regard to the product. After a few rounds with a particular product, I've done this. I'm sure everyone at some point has done this. But with NO prior history of the product, I don't see how it's done. Regards, Doug McKean - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: EMC STANDARDS
Hello Lou, A one stop hit site for a world wide listing of EMC standards is a very good idea!! Australia and New Zealand have adopted generally all IEC/CISPR and IEC/CENELEC standards in their original form and these standards are published as AS/NZS ..Number eg. CISPR 22 is AS/NZS 3548. Till now, generally, there has been a two year lag between EN and AS/NZS publications. While EM Emissions compliance is mandatory; Immunity is not mandatory at this point in time-but it will come! For Australia: www.standards.com.au email: nancy.l...@standards.com.au or m...@standards.com.au This site is maintained by Standards Australia www.aca.gov.au Email: s...@aca.gov.au This site is maintained by Australian Communications Authority (something like the FCC) For military testing: 461C or D is generally used. Hope this helps Arun Kaore EMC Engineer ADI Limited Systems Group Test Evaluation Centre Forrester Road, St Marys, NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au -Original Message- From: Lou Gnecco [SMTP:l...@tempest-inc.com] Sent: Thursday, 17 June, 1999 11:42 To: emc-p...@majordomo.ieee.org Subject: EMC STANDARDS Hello all, We would like to compile a world-wide list of sources of electromagnetic compatibility specifications and standards. We will publish this list under specifications and standards in our emc suppliers directory, see: http://www.tempest-inc.com/suppliers.htm So please e-mail us with the web sites for australian, canadian, chinese, japanese, etc. standards. we already have the IEEE, ANSI, IEC, and DLA (unclassified american military standards) we will list sources for automotive, medical and other specialized emc standards as well. thanks Lou - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
