Failure analysis and lessons learned on LHC experiments crate and power supply equipment

The LHC accelerator's first long shutdown period (LS1), in 2013–2014, has given the experiments the opportunity to perform planned upgrade and maintenance activities on systems and equipment. It has also been the right time to conduct a preventive maintenance campaign on crate and power supply equipment which is foreseen to operate smoothly for another 4 to 8 years. This paper presents the lessons learned during the LS1 power supply preventive maintenance activities as well as an in-depth analysis of the most common failure modes and weaknesses encountered on the power supplies in the LHC experiments over the past years of operation.