I do not understand all of it. Why using a low current fuse here ??? If this is a voltage measurement terminal, why should it be protected by a fast fuse ?
Fast fuses are used in current measurement circuits, not voltage measurement circuits as these are high impedance by nature. As they seem connected to the mains, I am sure they are high impedance enough ! Unless you are doing something very special, you might just insert a slow fuse at a higher value (say 4A slow-blow). The fuse has no role in the OV IV to OV II reduction, and is there only to prevent hazards if the protection circuit fails. Some testing should show if a shorted MOV would lead to a safe fuse blow. I second the other remarks made by Barry. I would replace all components (fuse MOV GTD) on each voltage step. This is a type test not a duration test, and test should be carried out on non-weared out components. Gert Gremmen ce-test qualified testing bv Van: Rob Oglesbee [mailto:[email protected]] Verzonden: woensdag 5 augustus 2015 16:29 Aan: [email protected] Onderwerp: Re: [PSES] IEC 61010-2-030 Transient Overvoltage Testing Brian, Actually, the fuses do trip on the first pulse that engages the MOVs (between 1.5kV and 2kV). The I2t is such that it doesn't take much (Littelfuse 508.500). Since this is a voltage measurement terminal not powered by the Mains it is measuring, we use as small a fuse as we can. We would use smaller, but the resistance of the fuses introduce too much error into the measurement. Rob From: Kunde, Brian [mailto:[email protected]] Sent: Wednesday, August 05, 2015 10:14 AM To: [email protected] Subject: Re: [PSES] IEC 61010-2-030 Transient Overvoltage Testing Robert, Your fuses should not blow, and we always test 5 positive and 5 negative at 0º, 90º, 180º and 270º. We also test at lower voltage levels, starting at 500V, the increasing to 1kV, 2kV, 3kV, and so on. By the time you get to 8kV your circuit would have been hit hundreds of time. You can probably change out your circuit as a point where you think your MOVs have served out its usefulness. But we have tested such circuits under thousands of hits without the MOVs failing, so just be aware. When the MOVs fail short, your overcurrent protection device will normally trip because once the Gas Tubes conduct they won't let go once the MOVs short. The Other Brian From: Rob Oglesbee [mailto:[email protected]] Sent: Tuesday, August 04, 2015 3:23 PM To: [email protected] Subject: [PSES] IEC 61010-2-030 Transient Overvoltage Testing I have a circuit I'm using to reduce the Overvoltage Category Level from 600V/CAT IV to 600V/CAT II before hitting an instrumentation transformer. I wish to test it per IEC 61010-2-030 Clause 14.101 (Circuits or components used as Transient Overvoltage limiting devices in measuring circuits used to measure Mains). The requirement is 5 positive and 5 negative impulses from a hybrid impulse generator at 8000V (1.2/50us O.C., 8/20us S.C., 2 ohms) while Mains is applied. Up to a minute is allowed between impulses. The pass criteria for the test is that no Hazard shall arise, and that the Mains breaker is not tripped. My circuit is a combination of MOVs and GDTs with fast fusing on both input legs. On the first impulse the protection circuitry will blow the fuses. My first question is, do I replace fuses between impulses (I think not)? My second question is, what phase angle should I perform the test at (I think worst case, +90 for positive and +270 for negative)? Thanks, Robert A. Oglesbee Radian Research, Inc. (765) 449-5505 This message, and any attachments to it, may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are notified that any use, dissemination, distribution, copying, or communication of this message is strictly prohibited. If you have received this message in error, please notify the sender immediately by return e-mail or call 765-449-5500 and delete the message and any attachments. 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) <http://www.ieee-pses.org/list.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]> ________________________________ 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) <http://www.ieee-pses.org/list.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://www.ieee-pses.org/list.html (including how to unsubscribe) <http://www.ieee-pses.org/list.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://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]>
