[no subject]
Hi, Section 4.4.5 of UL1950 appears to require a fire enclosure for essentially anything that contains a printed circuit board assembly The only exclusion appears to the that if the printed circuit board assemblies are 1) supplied by a power source that is limited to a maxmimum of 15VA under normal operating conditions and after a single fault. AND 2)the printed circuit assembly contains only a TNV circuit. The enclosure requirements are then defined in section 4.4.6. We have a max of 94Vrms on our cards (obviously isolated from SELV circuits) with a power less that 15VA. I am assuming that this means that a fire enclosure is necessary based upon my interpretation of the exceptions above (TNV requirement). Unfortunately, we are also trying to optimize air flow through the enclosure meaning that any type of screen or baffles (or anything necessary to make this a fire enclosure) significantly reduces the air flow. Is it possible to design the enclosure and then have it tested to A.2 to detemine if we meet the requirements of a fire enclosure.? just a thought. it seems that a fan located in a fire enclosure (and therefore compliance not necessarily checked) may be just as hazardous to the spread of fire out of the top of the enclosure. Any input or advise would be appreciated. jim stafford Carrier Access Corporation 5395 Pearl Parkway Boulder, CO 80301 - 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, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RTTE Directive
Hello All Re. recent question on above I am advised by the FEI (Federation of Electronic Industries UK) that RTTE 99/5 repeals TTE 98/13 and that 99/5 will cover satellites within it's scope. Alan E Hutley Editorial Publishing Director UK EMC Journal www.emc-journal.co.uk Fax 44 (0) 1208 850871
Re: Xenon Short Arc Lamp, Theatre Movie Projector, EMC Issues?
Two issues of emc will hit you. 1) the trigger for the arc This one is a pulse that is used to fire the arc. Usually, 20-30KV spikes that hit once a second until an arc generation is detected. The noise from these can be quite impressive, but at least they're not that broadband. 2) the standard noise from the switching PS *and* from the arc itself. I've seen several PS for arc lamps not comply at all. Maybe they did one day, but they don't now. We're talking probably 20-30 dB out of Class A compliance. The noise from the arc unfortunately did not get a chance to characterize that, but remember it is an avalanche type noise and is as husky as the current that's supplying it. - Robert - -Original Message- From: Donald Kimball dkimb...@qualcomm.com To: emc-p...@ieee.org emc-p...@ieee.org Cc: p...@qualcomm.com p...@qualcomm.com List-Post: emc-pstc@listserv.ieee.org Date: Friday, March 12, 1999 2:40 PM Subject: Xenon Short Arc Lamp, Theatre Movie Projector, EMC Issues? I am working on a project where some digitial signal processing electronics will reside inside of a digital movie projector for a large theatre. The digital projector does not use film. The projector will contain a Xenon Short Arc Lamp of up to 7kW. The ignition voltage for the lamp is 25-30kV. What are the significant EMC issues for such an environment? I am concerned about emissions from the power supply (i.e. ballast) used for the lamp, and susceptibility of the digital signal processor. I am trying to locate information on both the expected transient voltage and current waveform through the lamp, and the expected steady state voltage and current waveform through the lamp. Don Kimball - 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, j...@gwmail.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, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
re: Spare Change
Wonderful job! I cannot help admiring you. Have a nice weekend! Best Regards, B Ma - Original Text From: ed.pr...@cubic.com, on 3/19/99 9:36 AM: The Coins-in-a-bag thread has been moving from anecdote to anecdote for the past week or so. Let's take this to the next level---sloppy field testing! This morning, I procured two fresh, new 1 gallon size Baggies brand plastic food storage bags, a single Baggies brand sandwich storage bag, and $3.06 (6 cents, 7 nickels, 4 dimes and 9 quarters) in clean US currency. I cut a whip antenna to 25 cm length (banana/BNC adapter included), yielding a 1/4 wave antenna for roughly 300 MHz. I then used this whip as a monopole antenna connected first to my Tektronix TDS 640A oscilloscope (1 GHz real-time BW) and then to my HP-8562A spectrum analyzer. I placed the coins into one of the 1 gallon bags, and inflated it with a swooping motion through the air (my breath has high humidity). I held the bag only by the neck, trapping the air and causing the bag walls to bulge, approximating a 10 diameter sphere. I then vigorously shook the bag, at about 12 in front of the whip antenna, while observing the displays. ++ TEST RESULTS Oscilloscope, 5uS/div, 1 V/div Test 1: 2.46 Vpeak, with an exponential decay lasting over 45 microseconds and a TC of about 25 microseconds. The risetime is about 136 nanoseconds. A view of the acquired waveform and an expanded risetime view is attached as Coins.zip. Test 2: 2.64 Vpeak, similar decays. This has an interesting double discharge at the leading edge. An initial discharge triggers the scope, then another discharge hits about 500 nanoseconds later. A view of the acquired waveform and an expanded risetime view is attached as Coins.zip. Note: It only takes a few shakes to get a decently high discharge. And now, on to the spectrum analyzer. Similar test distance and conditions. Using a 1 MHz resolution bandwidth, a 1 MHz video bandwidth, 0 Hz span width, 0 dB of RF attenuation and peak hold trace. Test 3: 10 MHz 31 dBuV noise floor 59 dBuV transient noise peaks Test 4: 100 MHz 31 dBuV noise floor 62 dBuV transient noise peaks Test 5: 500 MHz 31 dBuV noise floor 70 dBuV transient noise peaks Test 6: 1 GHz 31 dBuV noise floor 66 dBuV transient noise peaks Test 7: 5 GHz 31 dBuV noise floor 50 dBuV transient noise peaks Test 8: 10 GHz 35 dBuV noise floor 40 dBuV transient noise peaks Test 9: 15 GHz 43 dBuV noise floor 47 dBuV transient noise peaks Test 10: 500 MHz 31 dBuV noise floor 70 dBuV transient noise peaks Note: I removed all coins except the 6 cents. Test 11: 500 MHz 31 dBuV noise floor 70 dBuV transient noise peaks Note: I removed all coins except the 7 nickels. Test 12: 500 MHz 31 dBuV noise floor 70 dBuV transient noise peaks Note: I removed all coins except the 9 quarters. Test 13: 500 MHz 31 dBuV noise floor 70 dBuV transient noise peaks Note: All coins back in the bag. Test 14: 500 MHz 31 dBuV noise floor 61 dBuV transient noise peaks Note: All coins back in the small sandwich size bag. (Maybe less vigorous shaking.) Test 15: 1 GHz 31 dBuV noise floor 53 dBuV transient noise peaks Note: All coins back into the gallon bag. I exhaled into the bag several times, causing visible condensation on coins and bag walls. The observed transients were far fewer numerically, and of lower magnitude. What this seems to show is: 1. There are measurable emissions present across the spectrum from 10 MHz to 15 GHz. 2. The emissions clearly stand out from the ambient noise level of an open industrial area. 3. It is easy to create several volts into a high impedance load. 4. The generated levels do not depend on having a mix of different coins. 5. One type of coin works about as well as any other. 6. High humidity within the bag inhibits noise generation. 7. It's time for lunch. Regards, Ed -- Ed Price 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: 03/18/1999 Time: 14:59:35 -- - 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, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Fw: RE: AC Adapters
Don't forget Argentina and Chile. They are different. BTW, everyone should get the latest copy of IEC 60083. This report covers the world pretty well. Ron Wellman well...@corp.hp.com Subject: Fw: RE: AC Adapters Posted for Wayne Thomas: From: wayne.d.tho...@exgate.tek.com Subject: RE: AC Adapters Date: Fri, 19 Mar 1999 08:52:26 -0800 To: jrbar...@lexmark.com, emc-p...@majordomo.ieee.org John, (And Group) We noticed that you did not mention China (GB 2099.1-1996). The layout is the same as the Australian (AS 3112) but the blades are thinner. If the thick Australian plug is pushed into the China socket it may damage it. It is our understanding that power cords for China require Certification as noted by the Great Wall Mark. Wayne Thomas Tektronix Inc. -Original Message- From: jrbar...@lexmark.com [SMTP:jrbar...@lexmark.com] Sent: Friday, March 19, 1999 6:52 AM To: emc-p...@majordomo.ieee.org Subject: Re: AC Adapters 2. How many different adapters are required to be stocked to handle the various requirements for plugs and safety approvals? We find that nine grounded-plug styles cover us worldwide: * UL 817.21 (NEMA WD-1 5-15P, US and Canada). * AS 3112 (Australia). * BS 1363 (United Kingdom). * CEE7 VII (Schuko, Europe). * SII-32 (Israel). * SEV 1011 (Switzerland). * SABS 164 (South Africa). * CEI 23-16 (Italy). * AFSNIT 107 (Denmark). For a 2-wire (double-insulated, Class 2) product the CEE7 XVI(2) Europlug could take the place of the CEE7 VII and SEV 1011 plugs. ---End of Original Message- -- Ed Price 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: 03/19/1999 Time: 09:10:58 -- - 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, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). File: Fw_ RE_ AC Adapters.TXT
