Single-phase A-C electric locomotives on the Pennsylvania Railroad - protection and tonnage rating

The single-phase electric locomotive is thought of quite generally as a piece of motive power for heavy traction service. To an electrical engineer, however, it consists fundamentally of electric motors geared to wheels with means for controlling the applied voltage to handle a variable load at varying speeds. From this point of view it is interesting to consider the protective features of the motors and their associated electrical apparatus to develop devices and methods which are necessary to guard against the hazards common to the operation of all electrical devices and those special to an electric locomoive. This paper will consider these features as they apply to the electric locomotives operating on the Pennsylvania Railroad.