Don, I don't think that there is any one standard on inrush current requirements on power supplies. I know that there are several standards out there that specify (directly or indirectly) inrush currents conditions depending on your end-product application, but I do not believe that you will find a standard dedicated in itself to the subject of inrush currents requirements. In addition to the standards listed below, you may want to take a look at the ETS300132 - "Power Supply Interface at Input to Telecommunications Equipment" - series of standards. They provide detailed descriptions on inrush currents requirements and measurements pertaining to telecommunications equipment. Regards, Bandele Adepoju Jetstream Communications, Inc. [email protected]
-----Original Message----- From: George, David L [mailto:[email protected]] Sent: Wednesday, June 21, 2000 10:37 AM To: 'Mark Gill'; '[email protected]'; [email protected] Subject: RE: Looking for Inrush Current Standard Mark; There are several standards. One was mentioned before (IEC61000-3-3). This standard is vague on its application to inrush currents but most people consider it also applies to inrush. Committee work in process clarifies this in the latest draft now out for vote. Maybe the vote is complete by now. This draft leaves no doubt about its application to inrush current. Another standard is IEC61000-3-5 titled: Limitation of voltage fluctuations and flicker in low-voltage power supply systems for equipment rated current greater than 16 A. Another standard is IEC61000-3-11 titled: Limitations of voltage changes, voltage fluctuations and flicker in public low-voltage supply systems - Equipment with rated current less than or equal to 75A and subject to conditional connection. This standard is in the FDIS stage and the voting period ends early July. Apparently this standard covers the entire range up to 75A and includes the ranges of 61000-3-3 and 61000-3-5. The above are so called emission standards and there in addition there are immunity standards. If you need information on immunity -please let me know. Dave George Unisys Corp. 2476 Swedesford Road Malvern, PA 19355 Tel: 1-610-648-3653 Fax: 1-610-695-4700 -----Original Message----- From: Mark Gill [mailto:[email protected]] Sent: Thursday, June 01, 2000 1:56 PM To: '[email protected]'; [email protected] Subject: RE: Looking for Inrush Current Standard Don - I have not heard of such a standard. Somewhat obvious, but general product safety requirements state that the inrush current must be limited such that overcurrent protection devices (either supplemental or branch circuit) are not opened in the course of normal operation of the product. This would be the upper limit for inrush, and depends upon the characteristics of the particular protector. Normally this is an end-product requirement, as compliance is affected by all passives and the particular supplemental protection (if any) in front of the supply in the final product. Unusually large decoupling capacitors (bulk) can sometimes require special circuits to limit the size of the inrush current. I am a bit unsure about the limits you mention below, specifically for t>500 ms, as normal operation of all products falls within this range and can well exceed this limit (infinite time implies steady state)! I hope this helps. Regards, Mark Gill, P.E. EMC/Safety/NEBS Design Nortel Networks - RTP, NC, USA -----Original Message----- From: [email protected] [SMTP:[email protected]] Sent: Thursday, June 01, 2000 9:03 AM To: [email protected] Subject: Looking for Inrush Current Standard I am looking for a standard or standards (IEC, EN or similar) which contain inrush current requirements for power supplies. The standard might require the inrush to be: <20A for 50 us<t<1.5ms, <10A for 1.5ms<t<500ms, 0.6A for t>500ms. Do any good standards exist on inrush current? Thanks, Don MacArthur ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
