If you see spikes when you rotate the turntable, it usually means there’s something wrong. There’s usually a PE type ground, that unless the used copper terminals to bond aluminum structure, and you have periods of moisture, then that should be good.
Just about every turntable I’ve seen has some form of brush or chain mail to connect the turntable to the ground plane. That’s a 360 bond and so should always be bonding the parts against charge. These brushes do need servicing periodically, maybe it’s past time for that in this case. Failing that, check for loose terminals, especially on the motor. If you have an EUT on the turntable, make sure parts aren’t rubbing Run an ambient too, just to make sure it’s truly caused by rotation. Sounds a fun problem to fix, good luck! Cheers, Derek. Sent from my iPad Pro On May 14, 2022, at 3:50 PM, Bill Owsley <000000f5a03f18eb-dmarc-requ...@listserv.ieee.org> wrote: ESD from flush mount rotating table. Floor mounted power receptacles were cabled to avoid brush noise from power connections. Cables in the crawl space under the raised floor, slide about as the turntable rotated, and the generated a static charge on cable insulation. Discharges could be seen in the dark and corresponded with received noise on SA. The easy solution at the time was about a case of ladies anti-static spray used to prevent dresses and panty hose from sticking together. Sprayed liberally all around the cable area. It would last a year or more. Low humidity was not an issue in south Florida, and there was still a static problem. On Thursday, May 12, 2022, 10:13:17 AM EDT, Paasche, Dieter <dieter.paas...@christiedigital.com> wrote: I dad that once, It was bad contact or loos contacts on the brushes to ground in addition to very dry and not compliant humidity condition. In theory I think you should have at least 30% humidity, 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: Paolo Roncone <paoloc...@gmail.com> Sent: Wednesday, May 11, 2022 12:22 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] ESD generated by rotating turntable CAUTION:This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe. Hi everybody we are considering doing radiated emissions scans during the turntable slow rotation (about 5min/360deg) in a chamber with turntable flush on the metal floor and sliding contacts. The likely issue is ESD generated peaks coming from the sliding contacts. Anyone has experience with this setup, and in that case, what kind of mitigation techniques (if any) would be available? I have direct experience with another chamber with a different kind of turntable (not flush, , wooden structure raised about 20cm from the ground plane) and have no issues in the 30MHz to 18GHz range. Thanks in advance Paolo - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
