Ted When, many years ago, I organised compliance testing at one of the HP UK sites, I used the same range (although I did use 270V = 250V +10%, at the top end) you mention below - and for the same reasons!
Similarly I used to test some equipment from 90V-135V in the days before full-range autoranging PSUs were common. I also only used to test again at the middle of these ranges (i.e. around 225V & 115V respectively) as experience showed that if a unit (admittedly, relatively low power computer peripherals) worked at the middle and ends of each range, there was little point (at least from a IEC 60950 perspective) of doing any the other possible combinations! (HP did, and I hope still does, design very good equipment and tests it well!) Had a lovely "discussion" with the CSA Category Certification Engineer when he complained that I was'nt doing exactly what it said in the CSA Standard. However, having presented and discussed with him, the voltage/current/safety component temperature results from various units, he nodded sagely and no more was said! (If only things in my current job were as simple!) John Allen From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 08 November 2006 04:28 To: [email protected] Subject: RE: Worst Case AC Power Conditions Hello Brian, 180 - 264 V may be a better range to use for voltage. Japan uses 200 V and you will want to be able to run at a 10% undervoltage. The Japanese are more particular about controlling voltage than most countries, so -10% should be acceptable. 180 V will test to -13.4% for the North American 208 V system and again, this should be sufficient based on North American power distribution. This test voltage will be -22% for the 230 V world which should give you reasonable coverage even for the areas that have some significant voltage dips and sags. There are quite a few areas that run at 240 V and it will be worthwhile testing to a 10% overvoltage for these areas. This is why I recommend 264 V. This is a less common condition than an undervoltage and the 10% testing for 240 V (15% for 230) should be sufficient. In general, you can expect the added cost to track the extension of the operating voltage range. It can be more difficult to determine sufficient limits for surge and transient testing. However, I have found that good design practices can often result in significant performance improvement without a significant cost increase. However, implementing the necessary changes cheaply can normally only be done early in a design. Proper grounding and bonding, reduction in loop areas and proper filtering is easy to design in from the start, but harder to retrofit. I know that this is a very simplistic answer to your question, but I can only give general guidance without detailed knowledge of your product. Best regards, Ted Eckert American Power Conversion Corporation The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC nor representing APC's official position on any matter. "Kunde, Brian" <brian_kunde@leco tc.com> To <[email protected]>, 11/08/2006 09:40 <[email protected]> AM cc Subject RE: Worst Case AC Power Conditions Ted, Thank you for your reply. We sell products worldwide to operate in the 200-260 (230V Norm) voltage range. The information I seek includes help in determining where to draw the line between real world power line conditions that a product should work properly in and the conditions in which a product is not expected to work properly in. Your statement in your second paragraph about manufacturers performing a cost-benefit analysis describes what it is we are trying to determine. Keeping in mind the cost of having personnel at a customer site for days or longer to try and determine a problem. Power line conditioners, which are very expensive for systems that can draw up to 40 amps, are often used to troubleshoot problems. In those cases where the conditioner seems to fix the problem we are trying to determine if the problem is our hardware not being designed immune enough or the power line conditions at some customer sites are beyond what is reasonable to expect a piece of high end analytical equipment to work properly in. Thanks again, The Other Brian From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, November 08, 2006 9:39 AM To: [email protected] Subject: Re: Worst Case AC Power Conditions Hello Brian, Can you provide a little more information for your first question? Into what regions will you sell your product? Worst-case conditions will vary significantly from one part of the world to another. Frequency is very stable in Western Europe and North America, but it can vary significantly in Africa, India and Southeast Asia. You can expect extended brown-out conditions in some areas and this can be more wide spread. Products sold in California will need to withstand significant voltage drops for extended periods. Many regions have either poor enforcement or lacking regulations for harmonic control, particularly in industrial applications. A product located near large industrial VFDs will be subject to significant interference. Most manufacturers can do no better than performing a cost-benefit analysis for their design. Make the product as robust as possible without incurring a significant cost increase. Then, provide clear documentation on the operating limits. Customers in areas with poor power control may accept the necessity of using power conditioning equipment with certain products. In regards to item 3, there are numerous options. I have worked with Dranetz equipment in the past, but there are plenty of options. http://www.dranetz-bmi.com/ http://www.aemc.com/ http://dentinstruments.com/ http://us.fluke.com/usen/products/category.htm?category=PQTTOP(FlukeProd ucts)&trck=rpm Best regards, Ted Eckert American Power Conversion Corporation The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC nor representing APC's official position on any matter. "Kunde, Brian" <brian_kunde@leco tc.com> To Sent by: <[email protected]> [email protected] cc Subject 11/08/2006 08:14 Worst Case AC Power Conditions AM Greetings, 1. Can anyone provide specifications for a "worst case" real world AC power line condition in which an apparatus is expected to operate properly in (pass/criteria A)? This would encompass a combination of harmonics, voltage variations, frequency variations, etc.. 2. Also, if anyone has a program for a California Instrument CTS system with a 5000ix power supply that could test for a "worst case" AC line condition, that would be helpful. I have heard that some companies have developed such a custom program to simulate poor power conditions from different parts of the world. Such a program would operate with the the provided CIgui32 program. 3. Can anyone recommend an AC Power Line analyzer that we can just plug-in and it will analyze the AC power conditions at different customer locations? Then we could take the results and program our 5000ix power supply to simulate those conditions in our lab. The reason I'm asking is that from time to time we have experienced problems in the field due to with poor AC power line conditions at some customer locations even though we test and comply with the standard tests that are required for CE (surge, burst, dips, etc). We want to develop an internal test standard that will minimize problems in the field. Thank for any help or advice you can offer. The Other Brian. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.1.409 / Virus Database: 268.13.32/523 - Release Date: 07/11/06 -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.409 / Virus Database: 268.13.32/523 - Release Date: 07/11/06 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
