Secondary selective system residual bus transfer - a modern application approach

A traditional secondary selective residual bus automatic transfer scheme is reviewed, and the basic logic necessary for automatic transfer operation is discussed. Although many transfer scheme documents are available, the authors believe the scheme complexity should challenge application engineers to better understand the "why\´s" rather than the "how to\´s" of the application. A modern programmable logic controller approach is proposed as a contemporary solution to a complex control application.