A choke in the safety ground could replace a common mode choke in the mains lines, but only if the enclosure of the filtered device is isolated from trolley structure completely, and the capacitance between equipment enclosure and trolley structure is controlled to provide a higher impedance than through the filtered safety ground wire (over the frequency range of interest).
If there is a short and the ground wire performs its function the choke will saturate and become ineffective but that is a moot point under short circuit conditions. During the time it takes the choke to saturate it will buck the increase in current and keep the shorting potential on the equipment enclosure; I expect this will be on the order of a millisecond or less and shouldn't be a safety issue, but there are lots of product safety people on the list who can weigh in on that subject more authoritatively than I do. on 9/11/03 4:03 AM, Paolo Peruzzi at paolo.peru...@esaote.com wrote: > > > > > > Dear all, > I'm involved in the design of a mains filter of a trolley and I'm > discussing with my colleagues about the convenience of inserting an > inductance on the protective earth conductor. I'm quite sceptical regarding > EMC advantages of such a solution, but I haven't much experience on that. > Have you any hints on the subject? > > best regards, > Paolo Peruzzi > > ************************************************** > Paolo Peruzzi > Esaote S.p.A. > Research & Product Development - Design Quality Control > via di Caciolle, 15 I- 50127 Florence > tel: +39 055 4229469 > fax: +39 055 4223305 > e-mail: paolo.peru...@esaote.com > ************************************************** > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: emc-p...@hypercom.com > Dave Heald: emc_p...@symbol.com > > For policy questions, send mail to: > Richard Nute: ri...@ieee.org > Jim Bacher: j.bac...@ieee.org > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > -- Ken Javor EMC Compliance Huntsville, Alabama 256/650-5261 This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
