All, Tim's comment made me think. In the past, I have seen hydraulic lines passed through waveguide feed-thrus that have re-inforced metal braid. Be aware of this if you need to pass hydraulic lines into your chamber or RF shielded enclosure. Alternatives do exist that are non-conductive.
Regards Frank Krozel http://www.electronicinstrument.com ----- Original Message ----- From: Haynes, Tim (SELEX GALILEO, UK) To: [email protected] Sent: Wednesday, January 14, 2009 6:26 AM Subject: RE: Anechoic Chamber: Pass-through vs. Bulkhead Hi All, Conventional wisdom is, as stated, to bond the shield of a cable, hydraulic pipe, or any other electrically conductive - non-energised item that penetrates the shield wall. This is usually done with a purpose made "bulkhead" connector and is, again, usually done at a purpose made access plate in the shield room wall. Energised items cannot be connected to the shield and here the conventional wisdom is to connect the energised conductor via a filter that has its local ground connected to the shield wall. However, it might be acceptable to use a pass-through pipe where the pipe is long and can provide a sufficiently high capacitance to ground to form a functional filter at the frequencies of concern. The capacitance might be increased by "stuffing" the pass through pipe with conductive wire wool. I once had no option but to "pass through" a cable into the chamber. The project allowed me to remove the outer insulation at the pass through and I bonded the cable shield to the screened room by using a bolt to apply pressure to a shim of metal that held the cable firmly to the metal of the pass through pipe. That worked well. I hope the information helps. Regards Tim ************************ Tim Haynes A1N10 Electromagnetic Engineering Specialist SELEX Sensors and Airborne Systems 300 Capability Green Luton LU1 3PG ( Tel : +44 (0)1582 886239 7 Fax : +44 (0)1582 795863 ) Mob : +44 (0)7703 559 310 * E-mail : [email protected] P Please consider the environment before printing this email. There are 10 types of people in the world-those who understand binary and those who don't. J. Paxman SELEX Sensors and Airborne Systems Limited Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL A company registered in England & Wales. Company no. 02426132 ******************************************************************** This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. ******************************************************************** - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.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]>
