Some problems in high-speed alternators, and their solution

It is the author´s purpose to present concisely some of the more interesting problems encountered, and the methods adopted to solve them. The problems, although encountered in high-speed alternators, will be found to be of interest to engineers engaged in other branches of the electrical engineering industry. The following subjects are considered:¿ (1) The history and failures of turbo-alternators. (2) Mechanical construction of rotors and caps supporting the coil ends. (3) Stator windings and insulation. (4) Stator slots. (5) Alternator ventilation, water cooling and the necessity for clean air supply. (6) Exciter instability. (7) Eddy currents in rotors. (8) Oscillograph tests, in explanation of exciter instability, showing the necessity for precautions when breaking the main field by means of a quick-break switch without any discharge resistance.