Electric Transmission and Control of Power From Internal Combustion Engines for Transportation

The use of electric transmission is almost a necessity with large internal combustion power plants in transportation service. Furthermore, the interposition of the electric transmission provides a method of obtaining what is the equivalent of a wide change in gear ratio, as well as a cushioning of the characteristic power impulses of the internal combustion engine. In adapting the internal combustion engine to this character of service there has been a number of problems, such as fitting the generator to the engine curve, the question of hand or automatic control, field control arrangements, single vs. multiple motor drive, and arrangement and operation of auxiliaries. The use of the combination generator-battery power plant has recently received considerable attention. This application employs a battery operating in parallel with the engine generator power plant, capable of supplementing the power of the engine for short periods. The characteristics of the engine used in transportation service must be well adapted to the duty required. These characteristics vary somewhat with the size of the unit and the control of the engine throttle is usually adapted to the particular problem in hand. In this paper, the principal problems connected with the operation and design of complete engine generator units are discussed in detail and many typical schemes of connection are diagrammatically shown.