Characteristics of Induction Conveyor Motors in the Generating mode

In a downhill conveyor system, the drive motors become generators feeding real power to the electrical system. A general method using the cascade network concept and a digital computer is proposed to study the conveyor motors´ operation in the motoring and generating modes. By use of the proposed method, a long downhill conveyor system with many stages of induction conveyor motor is studied. Various parameters are considered such as different types of feeder, the amount of shunt capacitor, and the amount of local load in parallel with the conveyor motors. Based on the computed results for the various cases, the electrical performance of a typical downhill conveyor system is summarized. From that, some engineering considerations are proposed to facilitate the design of a technically and economically sound downhill conveyor system. In particular, the conclusion may be drawn that the use of a cable feeder has many advantages, i.e., flat voltage profile along the feeder, relatively low line current and conductor loss, and avoidance of shunt capacitors. Furthermore, it is feasible to interconnect two substations when the conveyor motors are in the generating mode. The power (real and reactive) flow from the generators toward the two substations is affected by differences in the magnitude and angle of the voltage at each substation.