John, Yes, the large rf filter is still in the circuit but only supplying less than few amps of current to the 24Vdc power supply. The High Current Furnace branch would be an open circuit.
The worst case would be in a 50 amp (rated) instrument where we have a 65 amp RF Line filter driving a 500 watt 24Vdc power supply (about 1 amp at 50% load), when the furnace is not running. The furnace only runs about 30-60 seconds at a time per analysis. So it is off most of the time. I'm guessing that under some conditions, there could be some kind of interaction between the rf filter and the power supply which maybe causing our high fallout. Can you propose a test setup where we might be able to simulate such conditions? Thanks for the input. The Other Brian -----Original Message----- From: John Woodgate [mailto:[email protected]] Sent: Monday, September 21, 2015 4:40 PM To: [email protected] Subject: Re: [PSES] Unexplained High Fallout of Power Supplies In message <64D32EE8B9CBDD44963ACB076A5F6ABB02717398@Mailbox-Tech.lecotech.local>, dated Mon, 21 Sep 2015, "Kunde, Brian" <[email protected]> writes: >The word we get from the field is that these power supplies are failing >while the instruments are in Stand-by mode (running but not during an >analysis), meaning, the high current filter is not running at the time >of the failures. When you say 'it's not running', I understand that the furnace current isn't flowing, but is the filter connected to the mains supply? If so, that is possibly a more hazardous condition, because a filter with open-circuit output can produce high voltages. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk When I turn my back on the sun, it's to look for a rainbow John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> ________________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. Thank you. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> 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 <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
