Nice summary Rich Charles Grasso EMC Engineer StorageTek Tel:(303)673-2908 Fax(303)661-7115
>---------- >From: Rich Nute[SMTP:[email protected]] >Sent: Thursday, July 10, 1997 5:10 PM >To: [email protected] >Cc: [email protected] >Subject: Re: EN 61000-3-2/3 In the Great Scheme of Things > > > >Hello from San Diego: > > >I appreciate Eric's point of view regarding the harmonics >standard, EN 61000-3-2. However, I do have some rebuttal >remarks. > >(Understand that the products that I am responsible for >are less than 75 watts and therefore are Class A, not Class >D, under the standard. As such, the products do not need >PFC circuits. So, I am largely unaffected by the outcome >of the CENELEC BT effective date deliberations.) > >Personally, I disagree with the need for this standard. >I equate it to saying that you shall not place an inductive >load on the power line because it will cause a phase shift >which will affect other subscribers. But, power suppliers >do not say this, instead quietly installing capacitors at >strategic points on their own power lines to correct the >phase shift caused by customers' inductive loads. > >Power suppliers could likewise correct for non-linear loads >by installing "zig-zag" transformers at strategic points on >their own power lines. I'm sure these are more expensive >than capacitors, hence they don't want to do this. > >The problem could be minimized by constructing distribution >systems with much smaller LV loads and using more, yet >smaller, distribution transformers. In Europe, the LV >distribution can be as high as 600 homes, while in North >America the LV distribution is typically 8 homes! > >So, I don't like the power suppliers saying, on the one >hand, "We will correct for whatever inductive load you >connect to the system," while, on the other hand, "You >will correct for whatever non-linear load you connect to >the system." > >June 1, 1998, has been the "effective" date since the >standard was announced nearly 4 years ago. The date has >NEVER been changed, although there have been many attempts >to change (delay) it. > >As of today, effort is continuing to change the effective >date to January 1, 2001. I have NO knowledge as to who >is driving the proposal to change the date, nor do I know >the process, nor do I have any knowledge that suggests >a probability for adoption. > >The antics of those who have proposed a delayed effective >date together with the antics of the CENELEC BT have indeed >confused the situation. Nevertheless, there has been NO >official word at any time as to any change to the June 1, >1998 effective date. > >Here's an anecdote. In 1994, we started a new product >with lifetime expected to extend beyond June 1, 1998. We >developed two power supplies, one with PFC and one without >PFC. Our plan is to use the non-PFC until early 1998, >and then switch to the PFC power supply. The two power >supplies use essentially the same board, the non-PFC >having fewer parts. We continue to use the non-PFC after >June 1, 1998, for non-CE markets. > >In all of my postings to this group, I have been very >careful to say that you should not rely on my reports of >the efforts to delay the effective date. In my opinion, >a manufacturer must deal with the "official" effective >dates first, and have a backup plan to deal with a date >change. > >The current status is that June 1, 1998, is the effective >date for the standard. > >The risk of non-compliance is no or delayed sales in the >EC. > >The risk of early compliance is higher prices. > >The risk of a back-up plan is higher development costs. > >I don't like any of the choices! > > >Best regards, >Rich > > > >
