INTRODUCTION
The main connections bus bar (Fig. 14.1) connects the generator to its associated generator transformer. An aluminum tube (conductor) surrounded by a concentric enclosure of the same material is used for each phase of the generator. Since each enclosure is isolated from its neighbor, the term isolated phase bus bar (IPBB) is used.
The conductor of each phase is supported at the center of the enclosure by equispaced insulators. These insulators are rigidly fixed around the circumference of the enclosure. They allow limited radial movement of the conductor. The rating of the busbar installation is based on the temperature rise above a specified ambient at maximum load and its ability to withstand ground (earth) and three-phase short-circuit faults anywhere in the generator system without damage.