The Failure of the Alternators of the Nimrod Main Magnet Power Supply

The paper describes the failure of one of the two magnet power supply alternators which resulted in the rewind of one stator and the modification and rebuild of the rotors of both alternators. This failure prevented Nimrod operating at 7 GeV from late February, 1965 to the end of November, 1965. Certain design changes made when the rotors were rebuilt are described. A resume is given of the investigations carried out immediately after the failure, while rebuilding was in progress, and after the machines were returned to service. Present plans are also briefly mentioned.