Dear Ghery I don't think I disagree very much with what you said below. John Woodgate's summary yesterday was most interesting. He analysed the reasons why harmonic mitigation at system and site level were not being employed and concluded that: "It is almost axiomatic that the best overall economic solution (least total cost to the end-user) is the informed use of ALL technical solutions - mitigation at equipment, site and system level."
Unfortunately, many regulations do not necessarily appear to embody the best engineering approach to solving the problem they are supposed to be addressing. Regards, Keith In a message dated 23/01/02 16:21:36 GMT Standard Time, ghery.pet...@intel.com writes: > Subj:RE: EN 61000-3-3 compliant heater controller > Date:23/01/02 16:21:36 GMT Standard Time > From: ghery.pet...@intel.com (Pettit, Ghery) > Sender: owner-emc-p...@majordomo.ieee.org > Reply-to: <A HREF="mailto:ghery.pet...@intel.com";>ghery.pet...@intel.com</A> > (Pettit, Ghery) > To: cherryclo...@aol.com ('cherryclo...@aol.com'), > ghery.pet...@intel.com (Pettit, Ghery) > CC: emc-p...@majordomo.ieee.org > > One key reason the US (and others) computer industry objects to IEC > 61000-3-2 is that it was jammed down our throats with little or no input > from anyone other than the power providers. They conveniently set the > limits so that the full cost of resolving the problem would fall on > producers (and consumers) of devices utilizing the power they provide. No > standards were made that would require better design of the power > distribution system or consideration of facility level mitigation measures. > > Fixing the power supply of a personal computer to meet the requirements in > IEC 61000-3-2 is simple - spend money. The choke needed represents about a > 10% cost adder to the power supply. This is simply a cost, like taxes on > businesses, that is passed on to the consumer of the product. Fixing the > problem costs money, but typically large equipment to fix a problem over a > larger area is more economical than fixing it one load at a time. > > Let us agree to disagree. I remain an opponent of IEC 61000-3-2 as written > and hope that TC77/SC77A does a better job with the version they are > working on and that it better represents a compromise between those who > would put the entire burden on the loads (as they have already done) and > those who would do nothing. > > Ghery Pettit, NCE >
