Hi Chris, Muriel has clearly defined his EUT=his product. Your first scenario expanded the definition of EUT to (Product + a dedicated transformer). Is it appropriate?
Best Regards, Barry Ma ------------- Original Text From: "Chris Dupres" <chris_dup...@compuserve.com>, on 10/21/98 11:24 PM: ---------- Forwarded Message ---------- From: Chris Dupres, 100014,3703 TO: Muriel Bittencourt de Liz, INTERNET:mur...@inep.ufsc.br DATE: 21/10/98 19:12 RE: Copy of: Doubt on LISN utilization Hi Muriel. You asked: <I'm doing some tests of conducted emission using a LISN. My commercial voltage level is 220 V, 60Hz. But the product i'm testing is 110 V. So, i'm using a transformer before the LISN this way: Mains => Transformer(220/110) => LISN => EUT ( Equipment Under Test ) My questions are: # am i doing right? # is it possible to use a transformer? # isn't the transformer acting like a "unintentional" filter? > It's simple. There are two scenarios. 1. If the equipment is to be used at 220V, then test it with the actual transformer that will be used to provide 110V, AFTER the LISN. Think of the 110V transformer and the EUT in a cardboard box. All you are doing is providing 220V, you aren't particularly interested in what happens in the box, only in the emissions. The transformer is critical to emissions, as you suggest, and will attenuate emissions very usefully. That's why you should place it AFTER the LISN so that you can measure that attenuation. 2. If the equipment is to be used at 110V, then place the 110V transformer BEFORE the LISN, so that the LISN gets to see the actual emissions from the EUT before they get to the transformer. Hope that helps. Chris Dupres Surrey, UK. --------- 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).
