APPARATUS FOR CONTROLLING AND REGULATING A CUTTER HOIST

摘要

Motor control system for a mining machine of the type in which a cutting element is driven by a first electrical motor and the mining machine is advanced into a coal face by a second motor. The system is characterized in that the torque and speed of the second motor are reduced both when the cutter element drive motor is idling as well as when the cutter motor is overloaded. The arrangement is such that as the cutting element approaches the coal seam and is idling, the speed of the advancing drive motor is relatively low; when the cutter enters the coal face and the current to the cutter drive motor increases, the speed of the advancing drive motor is also increased; and when the cutter element drive motor is overloaded, the advancing drive motor is reversed to withdraw the cutting element from the coal face and thereafter again advances the cutting element into the coal face in a pulsing or reciprocating motion.