Hi all, in these cases (floating metal parts of EUT) we connect the floating part to Earth Ground with a 2x 470kohm cable similar (or same) as that used for VCP/HCP.
See IEC/EN 61000-4-2 sec. 7.2.4 Ungrounded Equipment: "A cable with 470 kohm bleeder resistors, similar to the one used with the HCP and VCP is the preferred device to remove charges; see 7.2" Regards Paolo On Thu, Mar 12, 2020 at 7:08 PM Paasche, Dieter < [email protected]> wrote: > Hi > > > > I had a similar situation. We ended using the alternative test method, > with just extending the time between discharges. As per IEC 61000-42 > Section 7.4.2.1: > > > > Therefore as an alternative, the following options may be used: > > − the time interval between successive discharges shall be extended to > the time necessary to allow natural decay of the charge from the EUT; > > > > Sincerely, > > > > Dieter Paasche > > Senior Product Developer, Electrical > > CHRISTIE > > 809 Wellington Street North > > Kitchener, ON N2G 4Y7 > > Phone: 519-744-8005 ext.7211 > > www.christiedigital.com > > > > This e-mail message (including attachments, if any) is confidential. Any > unauthorized use, distribution or disclosure is prohibited. If you have > received this e-mail message in error, please notify the sender by reply > e-mail or telephone and delete it and any attachments from your computer > system and records. > > > > *From:* DEREK WALTON <[email protected]> > *Sent:* Thursday, March 12, 2020 1:31 PM > *To:* [email protected] > *Subject:* Re: [PSES] ESD - Floating metal knob, otherwise grounded > equipment > > > > Oh Boy Elliott, > > > > you’ll get a few answers here, lol. > > > > My 10 cents is that when you are not discharging each time you are adding > more and more charge to the isolated control, that eventually will snap > over At that point you are discharging quite a significantly higher level > of chart than an individual event. > > > > I would not call that a realistic “ compliance” test. > > > > OTOH, if it’s possible that may happen in the real world with an operator > continually adding charge as they use your EUT, you may want to find a way > of adding some way to bleed charge over a few seconds. > > > > Interesting problem, lets see what others say, > > > > Sincerely, > > > > Derek > > LFResearch and SSCLabs.com > <https://nam03.safelinks.protection.outlook.com/?url=http%3A%2F%2Fssclabs.com%2F&data=01%7C01%7CDieter.Paasche%40christiedigital.com%7C87b43028e46b44b73cfc08d7c6aa41c9%7Cdf46f062ad2c407688e6c675c789a0d8%7C1&sdata=4XzbEqYHDMuBVctnJ7sALzrBEmoy%2B3W8dTZQ8Vz13xc%3D&reserved=0> > > > > > > On Mar 12, 2020, at 10:53 AM, Elliott Martinson < > [email protected]> wrote: > > > > Hi Everybody, > > > > We’re having some disagreements regarding the 61000-4-2 standard. In the > section “ungrounded equipment”, it states that ungrounded equipment or > part(s) of equipment shall have the charge removed in between ESD pulses in > order to not over-test. > > We have a product that only fails pre-compliance when repeated ESD pulses > are applied to a floating metal knob without removing the charge in between > (eventually there is a second discharge between the knob and the > enclosure). The product as a whole is “grounded equipment”. > > Since the issue only happens when the charge isn’t removed in between > pulses, is this a pass or a fail? > > > > Thanks, > > > > Elliott Martinson > > Controls Engineer > > Sub-Zero/Wolf > > [email protected] > > - > ---------------------------------------------------------------- > > 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]>
