Summary of Fuse Testing for Barrel Module Fuse Boxes - PowerPoint

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					Summary of Fuse Testing for
 Barrel Module Fuse Boxes
        Duke University
         Jack Fowler
 Fuse Box Production Summary
• Fuse Boxes have been in production for ~ 12
  months
• 35 sets of each type are being produced
• This involves > 7500 fuses
• Fuses were delivered from Oct 03 until Aug 04
     Fuse Box Production Steps
• Assemble Fuse Box components and solder
• Test Fuse Resistance
• Clean Fuse boxes and dry
• Test Fuse Resistance
• Dry fuse boxes for minimum 3 hrs at < 55° C
• Conformal coat fuse box components
• Final Test Boxes - continuity at < 100 V and check
  for breakdown at 2 kV
• Final assembly – add hardware and heat shrink and
  label cables
Fuse Boxes
       Post Production Tests
• Once fuse boxes are through the final test, we
  perform simple resistance test on each of the
  fuses.
• In the period of time between tests, the fuse
  boxes are stored on a shelf in the lab.
Failed Resistance Test Post Production
                   Fuse Recovery
• The recovery was performed by applying ~ 600 V through a
  6 MΩ resistor to all of the fuses. This applied ~ 100 µA
  current. This was applied for 1 minute.
• The fuse resistance was tested and the results recorded.
Fuse Recovery
      Fuse Conditioning after Recovery

• After recovery, all of the fuse boxes were connected in parallel
  and a 100 µA current was applied.
• The fuse boxes were left in this condition.
• After 2 weeks, half of the boxes were removed and the fuse
  resistance was tested. This included ~3500 fuses.
Fuse Box Conditioning
Fuse Box Connections
Fuse Tests after Two weeks of Conditioning
                         Summary

• Before recovery and conditioning, fuse failures seemed to be
  stabilizing at ~ 0.1 % per week.
• Recovery was successful for 60 % of previously failed fuses.
• After 2 weeks of conditioning, 33 % of “recovered” fuses
  failed.
• During 2 weeks of conditioning, an additional 8 fuses failed.
  This equates to ~ 0.1%/week.
• An additional 3 of the “recovered” fuses failed 1 week later
  bringing the failure rate to 40 %. No new fuses failed.
                      Future Plans

• Continue conditioning for the remaining half of the fuse boxes
  for 2 more weeks.
• Continue testing post conditioned fuses weekly for additional
  failures.
• Continue new design of fuse box without fuses. Resistors will
  take the place of the fuses.

				
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