I'm probably just restating Donald's note below but / means that it has two distinct inputs 120 or 240. The hyphen indicates a continuous range of operation from 120 through 240. The definition is buried in EN60950 somewhere but I forget exactly where. That of course doesn't mean that it matches NEC necessarily. Added note to Don's last paragraph, in the case Don speaks about generally one has to worry about brown out conditions which are below the input tolerance. South America I believe still has many instances of brownout conditions as their capacity doesn't match the demand on lots of days. Don likely has a much better handle on where, when and how brownout conditions occur. My designs of old, essentially monitored the voltage a force a graceful shut down before damage could occur to the equipment.
Gary -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Friday, January 27, 2012 8:13 AM To: [email protected] Subject: Re: [PSES] Is this common knowledge - Electrical Ratings Perhaps these days are long past, but there was a time when some switching power supplies were designed as 120/240 supplies without a mechanical switch. They used two energy-storage capacitors in series. At low line voltage, the input rectifier diodes were configured (electronically) as full-wave voltage doubler, charging the two-capacitor combination to the peak-to-peak line voltage. At the high line voltage, the diodes were configured as a bridge to charge the series combination of capacitors to the 0-peak line voltage. Note that although these supplies would operate from nominal 120 VAC or nominal 240 VAC, there was a range of voltages in between where they would NOT operate! Donald Borowski EMC Compliance Engineer Schweitzer Engineering Labs Pullman, WA, USA From: Kevin Robinson <[email protected]> To: emc-pstc <[email protected]> Date: 01/27/2012 07:23 AM Subject: Is this common knowledge - Electrical Ratings Sent by: [email protected] Happy Friday everyone I am asking a question that I already know the answer to, but I am trying to determine if it is common knowledge or if it was something that I picked up along the way and have always accepted as being true. If you were to see a product with a marked electrical rating of 120/240 V and another product with a marked rating of 120-240V, what would be the difference between these two products? Would a user or operator need to do anything special with one or both of these products to use it at 120V or 240V? Thanks, Kevin Robinson OSHA - ---------------------------------------------------------------- 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://listserv.ieee.org/request/user-guide.html 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]> - ---------------------------------------------------------------- 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://listserv.ieee.org/request/user-guide.html 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]> - ---------------------------------------------------------------- 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://listserv.ieee.org/request/user-guide.html 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]>
