We use a bank of lead-acid batteries. Haven't tried it, but if your test is going to run a long time you could probably connect an electronic power supply to keep the batteries charged.
A related issue is the residual pulse voltage at the power input port of the decoupling network (applies to both burst and surge). This cannot be reduced much below that which is allowed in the standards without compromising the wanted waveform. Electronic power supplies may or may not tolerate this, depending on their output impedance at other than DC and protection circuitry. I have heard a story of a dramatic interaction between a switching AC inverter and a surge generator, resulting in the destruction of the generator as a result of this residual energy pulse. Apparently one or the other can/will blow up, depending on which one has greater current/power capacity. We use linear AC inverters and have never had this problem. A motor-generator setup is another solution. Best Regards, Mike From: Derek Walton [mailto:lfresea...@aol.com] Sent: Thursday, October 03, 2013 7:48 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] EFT Generator series inductance I'll premise my reply by saying I could be wrong.. BUt... My understanding to the Decoupling network in the CDN is to prevent common mode noise from leaving back to the power source. The concept is not to insert differential mode impedance. Any DM impedance there is is likely due to leakage inductance, and more than likely will be less than typical power wiring. We meet this problem on some designs because they can't cope with even the LISN impedance, or the EMI room power line filters. So, MHO is that the power supply you are testing doesn't have enough internal capacitance. In the real world, the wires leading from the power source to your power supply will have significant inductance, and you need to be able to function with that by making short term energy needs are available inside the power supply. Next opinion please :-) Derek Walton L F Research -----Original Message----- From: John Woodgate <j...@jmwa.demon.co.uk<mailto:j...@jmwa.demon.co.uk>> To: EMC-PSTC <EMC-PSTC@LISTSERV.IEEE.ORG<mailto:EMC-PSTC@LISTSERV.IEEE.ORG>> Sent: Thu, Oct 3, 2013 9:37 am Subject: Re: [PSES] EFT Generator series inductance In message <20674C50F7E3794CA35FDCAD2B0E494027996D4A90@hubmail>, dated Thu, 3 Oct 2013, Kannan Dhamodaran <kan...@india.tejasnetworks.com<mailto:kan...@india.tejasnetworks.com>> writes: >I?m facing a problem while connecting 48V DC-DC converter, with >6A >input current, to EFT generator CDN. DC supply fed through CDN is >unstable and produces huge ripple that leads to my DC-DC converter >shutdown. This is observed while just powering ON and EFT not applied. I think that some converter techniques can be intolerant of supply inductance in the way you report. The incremental input impedance of the converter can look like a capacitor in parallel with a negative resistor, so oscillation might occur with an inductive supply. The resistor is negative because the output current and voltage are kept constant, so that if the supply voltage decreases, the input current has to increase. One to frighten the standards committee with! -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk<http://www.jmwa.demon.co.uk> If dictionaries were correct, we would only need one, because they would all give the same information. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@radiusnorth.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
