Description of the 45,000-Kv-a. Queenston generators

Notwithstanding the very large rated capacity of the 45,000-kv-a. generators for the Queenston power house of the Hydro-Electric Power Commission of Ontario, their essential construction features are not different from those of much smaller rated generators. The generators are of the vertical shaft type with two guide bearings, and a thrust bearing. The thrust bearing is located above the stator and carries the weight of the complete rotating elements of the generator and water turbine. Each generator is provided with a direct-connected exciter. The flywheel effect required for satisfactory speed regulation of the turbines necessitated the use of auxiliary flywheels mounted on the shaft adjacent to the generator rotor. The rotor is constructed with a number of cast steel wheels which together form the rotor spider for carrying the pole pieces. The pole pieces are made of punchings and are attached to the rotor with three dovetails per pole. The coils are made of copper strip wound on edge. The stator frame is split vertically into three sections to conform with foundry and shipping limitations but the core is built up without being split. The stator windings consist of form-wound, diamond-shaped coils, each slot containing two coil sides. The coils are made of stranded conductor and are insulated with mica tape, which affords more or less flexible insulation. The ends of the coils are braced against the distorting effect of severe short circuits in such a manner as to permit expansion and contraction of the copper without injury to the mica insulation. The armature phase connections are made with bus rings supported from the stator frame, making all connections accessible.