1 / 25

Mech Systems Proposed EMI Modifications

Mech Systems Proposed EMI Modifications. Marc Campell 9/2/03. EMI Skirt on Grid. Finding 3 - E-Nickel on Grid. Issue: Electroless nickel on Grid at CAL (and TRK, ACD & Radiator) interfaces is “better” than alodine on Aluminum Implementation plan is the concern

tracy
Download Presentation

Mech Systems Proposed EMI Modifications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Mech Systems Proposed EMI Modifications Marc Campell 9/2/03

  2. EMI Skirt on Grid Mechanical Systems EMI Impacts

  3. Finding 3 - E-Nickel on Grid • Issue: Electroless nickel on Grid at CAL (and TRK, ACD & Radiator) interfaces is “better” than alodine on Aluminum • Implementation plan is the concern • Sequence of Grid plating, insert installation and higher level drilling operations; • Grid requires high emissivity outer walls and • Masked areas for bonding operations • Grid has 2000+ holes so masking/plugging holes is non-trivial Mechanical Systems EMI Impacts

  4. CAL – Grid Interface Mechanical Systems EMI Impacts

  5. Finding 3 - E-Nickel on Grid (cont) • Impacts • Grid Mfg plan • Grid drawing note callout and masking details on drawing • Schedule • 4 x 4 Grid Mfg plan due by early Sept • 4 x 4 Drawing due mid-Sept • Drop dead decision date mid Oct (with impacts) Mechanical Systems EMI Impacts

  6. Findings 5 & 6 – EMI Shield Butt Joints • Issue: Butt joints may leak • 2 types of butt joints - edge on and flange as shown • EMI skirt to X-LAT plate • EMI skirt to Grid • EMI skirt to EMI skirt • EMI skirt to connector patch panel • Possible improvements • Tongue & groove joint • EMI gasket in groove • Conductive bond between components Mechanical Systems EMI Impacts

  7. EMI Skirt Joints Mechanical Systems EMI Impacts

  8. EMI Skirt Joints 2 Mechanical Systems EMI Impacts

  9. 5 & 6 – EMI Shield Butt Joints (cont) • Tongue and groove or gasket • Looks difficult to implement on grid especially near S/C interface & other Grid shear bosses • Plausible for some skirt to skirt joints and some areas of the X-LAT plate to EMI skirt away from heat pipe exits • Radiator Mount Bracket & Heat Pipe Patch panels could be conductively bonded to each other & the Grid (no planned removals after Grid Assy) Mechanical Systems EMI Impacts

  10. 5 & 6 – EMI Shield Butt Joints (cont) • Impacts • 6 (x 2) skirt drawings (90 Mhrs) • Grid drawing including possible redesign (& analysis?) of shear bosses (80-120 Mhrs) • X-LAT plate is awaiting final definition • Schedule • EMI skirt drawings needed late Sept • Being analyzed now • Consider EMI test of EMI skirt box to isolate specific problem areas & to define magnitude of problem Mechanical Systems EMI Impacts

  11. Finding 7 – 3 Piece X-Lat Plate • 3 vs 1 piece X-LAT trade is currently under study • Issues • Alignment of X-LAT fasteners to E-box inserts for direct bolting of X-LAT plates • LM tooling impacts & VCHP alignment • Tolerance of butt joint is an issue at EMI skirts • LM cost & producibility • Schedule • X-LAT design finalized mid-late Sept Mechanical Systems EMI Impacts

  12. 3 X-LAT Plates Mechanical Systems EMI Impacts

  13. X-LAT Butt Joint Mechanical Systems EMI Impacts

  14. Finding 9 – Venting of EMI Box • 2 choices • 1) Vent through X-side EMI skirt(2-4 in2 req’d) • 2) Vent through CAL baseplate crenulations, past TRK’s and out between ACD to Grid gap • 1) is straight forward, but effective 550 kHz filtered vent must be designed (commercial filters for 10’s MHz to GHz) • 2) is convoluted path past TRK & CAL cables • If analysis is not robust, a test may be required Mechanical Systems EMI Impacts

  15. Finding 9 – Venting of EMI Box (cont) • Impacts • 2 EMI skirt drawings (20 Mhr) • Design, develop & test a filter/vent (120 Mhr) • Schedule • EMI skirt drawings late Sept Mechanical Systems EMI Impacts

  16. Finding 11a – Radiator Level EMI Test • Issue – S/C regulated power and LAT heater control box will send noise down to strip heaters mounted on Radiator which may emit noise • LM can be directed to do best practices for EMI shielding of TCS components • LM can’t do this test without S/C regulated power & LAT heater control boxes • Finding a problem at the LAT level test is too late • Needs to be worked at SLAC upfront Mechanical Systems EMI Impacts

  17. Finding 11a – Radiator Level EMI Test (cont) • Impact • LM did not cost this test in their Phase II proposal • Cost & schedule impacts to Radiator delivery • Schedule • Radiator is on a day for day slip until spec gets released including resolving this issue Mechanical Systems EMI Impacts

  18. Finding 11b – LAT Level Radiator EMI Test • Radiators should be installed for LAT level EMI test • Agree • I&T needs to access impacts to current flow • S/C regulated power needs to be available • Systems Engr. needs to revise LAT Test Plan Mechanical Systems EMI Impacts

  19. Finding 12 – Radiator – Grid Interface • Current design has G-10 spacer between Radiator and its mounting brackets to limit heat leak into Radiator (in survival mode) to less than 5 watts • This electrically isolates the 2 parts • 2 options • Ti spacers with reduced area &/or increased thickness • G-10 spacers wrapped in thin foil Mechanical Systems EMI Impacts

  20. Radiator Mount Brackets Mechanical Systems EMI Impacts

  21. Finding 12 – Radiator – Grid Interface (cont) • Impacts • LM needs to analyze these options for thermal & structural performance • Schedule • LM waiting to fab Mechanical Systems EMI Impacts

  22. Back ups Mechanical Systems EMI Impacts

  23. EMI Box +Z up Mechanical Systems EMI Impacts

  24. EMI Box –Z up Mechanical Systems EMI Impacts

  25. X-LAT Joint Mechanical Systems EMI Impacts

More Related