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Dobite Outlook za Android<https://aka.ms/ghei36> ________________________________ Od: Boštjan Glavič <[email protected]> Poslano: sreda, 3. marec 2021 20:15 Za: [email protected] Zadeva: Re: [PSES] Determination of Maximum transient voltage on naval ships Hi Charlie Table 11 is for temporary overvoltages and rated voltages ( frequencies up to 30kHz). Table 15 is for transient overvoltages. Don't mix that values. I gues for ship you have no temporary overvoltage unless ship can be connected to AC mains in the harbor. In case it is connected, you have to use 2000Vpk or you can do calculation of temp overvoltage acc 60664-1. Input for T15 is transient overvoltage. Don't forget that for table 15 you have alternative option with hipot test from table 16. As explained by Rich, you have already determined very low value. Best regards Boštjan Dobite Outlook za Android<https://aka.ms/ghei36> ________________________________ Od: Richard Nute <[email protected]> Poslano: sreda, 3. marec 2021 19:43 Za: [email protected] Zadeva: Re: [PSES] Determination of Maximum transient voltage on naval ships Hi Charlie: If the ship can be connected to shore power, then the ship may be subject to “normal” (shore-based) transient voltages, in which case your equipment must meet the clearances for 2,000 volts peak. However, the specified at-sea ship-board 1,000 volts peak is reasonable since lightning strikes on overhead wires is unlikely. According to Table 10, the clearance dimension for 1,000 volts peak is 0.26 mm (0.8 mm for pollution degree 3), and for 2,000 volts peak is 1.2 mm. These are very small distances. Chances are the equipment has clearances greater than 1.2 mm, so it meets both 1,000 and 2,000 volts peak criteria. (Dimensions of a fraction of a millimeter require special control.) If you are planning on third-party certification to 62368-1, I would expect that the certification house would insist on 2,000 volts peak and the 1.2 mm clearance despite ship-board 1,000-volt transient voltage. Stay safe, and best regards, Rich From: Charlie Blackham <[email protected]> Sent: Wednesday, March 3, 2021 8:23 AM To: [email protected] Subject: [PSES] Determination of Maximum transient voltage on naval ships All I’m currently doing a LVD safety assessment for a rack of Radio Communication equipment going onto naval ships and using EN 62368-1 The equipment is powered at 115 60 Hz Clearance distances are based on maximum transient voltages which for normal (shore based) installations is given as 2000 V for 115 V installations per EN 62368-1 clause 5.4.2.2 referencing 5.3.3.2.3 of IEC 60664-1:2007 The 115V AC system on a ship is not subject to the same over voltage transients as land based equipment Google has found US publication S9086-KY-STM-010/CH-320R2<https://fas.org/man/dod-101/sys/ship/nstm/ch320.pdf>, Naval Ships’ Technical Manual Chapter 320 Electric Power Distribution Systems Maximum voltage transient of 1000 V on 115 V systems – this is also in MIL-STD-1399-300-1<http://everyspec.com/MIL-STD/MIL-STD-1300-1399/MIL-STD-1399-SECT-300_PART-1_55833/> TABLE II. Characteristics of shipboard electric power systems I’m basically trying to determine the minimum Clearance requirements to be applied so that the client can CE mark the system – is it reasonable to use this 1000V for determining required clearance in Table 11? Or, any reason why it’s not reasonable ? Thank you in advance for your thoughts Best regards Charlie Charlie Blackham Sulis Consultants Ltd Mead House Longwater Road Eversley RG27 0NW UK Tel: +44 (0)7946 624317 Email: [email protected]<mailto:[email protected]> Web: https://sulisconsultants.com/ Registered in England and Wales, number 05466247 - ---------------------------------------------------------------- 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 <[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]>
