Hi Wm (my guess is William), Didn't see a response to your question. Got lots to do today, so I'll be quick and dirty. (Well I thought I would...as you can see it wasn't so quick but it is dirty :-)
Test equipment... Surge Testing... There are quite a few companies that make equipment that can test this. Haefley, Compliance Design, Schaffner and Keytek come to mind. We use a Keytek CE-Master. It will handle most power line surge testing that would be required. However, it won't do the 10/700 waveforms for telecom surge (unless they have a new unit or new module). It also may have trouble surge testing signal lines and other non-power lines unless you get the proper coupling/decoupling network. Dips & Interrupt (also known as Power Quality Failure (PQF) testing... Same manufacturers as above. We use the CE-master for this test as well. (This is not a commercial for CE-master...it's just what we have.) One caveat regarding dip and interrupt testing is that you need a power source capable of high in-rush capacities to power the device under test. We use a typical wall outlet with a non-current limited isolation transformer to make 230VAC. If you use a current limited 110-230VAC converter, it may not be able to provide enough in-rush to test fairly. (check out the manual, it will explain) Oh yeah, I just remembered. Most of the standards say to test for 1 cycle of 50Hz. The CE-master will not generate 50Hz for you, instead it will only pass your 60Hz through it. We get around this by testing for two cycles of 60Hz instead of one cycle of 50Hz. It's a worst case, and keeps us from having to buy a 50Hz inverter (that isn't current limited...see above). Mitigation techniques... Surge. Depends upon the surge level needed to pass and the sensitivity of your equipment. Protection could be provided by the typical EMC filtering that you already have. (i.e. a power line filter with caps and chokes). If the surge is too powerful for your existing filter, you can either get a surge rated input filter or put a surge protection device on (watchout for your leakage current specs for safety). I recommend either a TVS or Sidactor. I used to worry about Sidactor availability as they were only available in 2,500 piece quantities, but are now available in small quantities from Digikey. Some manufacturers: TVS diodes....Semtech, Protek Sidactors... Teccor, Rachem Polyswitch. Dips & Interrupts. Main mitigation technique here is bulk capacitance to provide enough hold-up time so that your equipment doesn't power down during a small dip or interrupt. If you are using a power supply in your design, check out its hold-up time spec. So far, from our experience it appears that a supply with at least a 15milllisecond hold-up time will get you through the test. In rare instances, in-rush limiting may be required. Probably not. Exemptions? "Class A" is an emissions classification under the standard (EN 61326-1). Using "Class A" as an immunity classification may lead you down the wrong path. I would suggest considering immunity independently of emissions and classifying the equipment for immunity as "industrial" (annex A), "controlled EM environments" (annex B) or "portable" (annex C). Once you have picked the correct annex, the question "to test or not to test" will be answered. In order to determine the test level and performance criterion, use the annex picked above and then refer to Table 2 and classify your equipment as for "essential operation", "continuous unmonitored operation", "continuous monitored operation" or "non-continuous operation". There is also a Table 1 which specifies an absolute minimum immunity level for EN 61326-1 classified equipment. I use this as a benchmark, but usually test to higher levels as specified in the annexes. I hope there was something useful in there for you. Chris Maxwell | Design Engineer - Optical Division email [email protected] | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | > -----Original Message----- > From: [email protected] [SMTP:[email protected]] > Sent: Monday, November 19, 2001 11:29 AM > To: [email protected] > Subject: Methods & Equipment; Surge & Dips > > > Esteemed listmembers, > > In gearing-up for testing under the auspices of EN61326:97, I'm trying > to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 > (dips immy). Is there test equipment one can rent to conduct these > tests? What sort of mitigation steps are typical. Is anyone aware of > any exceptions for this testing under ClassA rules? > > Thanks in advance... > Wm Flanigan > Standards Engineer > Ameritherm Inc > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: [email protected] > Dave Heald [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > No longer online until our new server is brought online and the > old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
