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Cabling Team Challenges – ATLAS New Small Wheel in b. 191

14 DECEMBER,2021 | By Gianluca Canale and the Cabling Team

NSW
The ATLAS New Small Wheel, to whose assembly the CERN Cabling team contributed. (CERN-PHOTO-202105-072-69)

2021 was intense in terms of the amount and variety of work for the de-cabling and cabling campaigns particularly for ZDC and ATLAS New Small Wheel. It took 9 months, with 700 hours of services, but our team of experts successfully managed to complete all jobs against the clock and finally fit into the tight ATLAS NSW planning. Excellent job performed by all of you, and for illustration some NSW examples

Cabling Team provided full support to NSW on:

  • Qualification of contact/wire terminations
  • Assistance on definition of temperature crash tests on contacts
  • Total replacement campaign of connectors on multiple systems • High-voltage tests using HiPotCT all around the wheel, working at height on the cherry-picker
  • Raising awareness regarding critical quality issues of electrical connections
  • Training of NSW personnel to perform connectorization following evaluated quality procedures (the “rulebook”)

While commissioning of first sectors, ATLAS NSW noticed:

  • Dramatic increase of temperature on connectors
  • Loss of electrical connections
  • Voltage break-down while applying high-voltage

ATLAS NSW requested expertise of the BE-EA Cabling Team

On short notice, our Cabling Team analyzed the defective findings retrieved from NSW and concluded that the work previously performed presented:

  • Wire preparation not according to the “rulebook”
  • Non-conform crimping
  • Wrong termination method (crimping instead of soldering and vice-versa)
  • Poor workmanship

Cabling Team performed Root Cause Analysis on defective samples:

  • Connector/contact references not tested for specific application & environment
  • Wrong contact reference chosen without considering the correct current derating
  • Usage of not conform and worn tooling
  • Manufacturer’s indication on termination method (crimp, solder) not followed
  • First received quality likely constrained by the initial work which had not been performed by specialized personnel