Early mine hoists motors were speed controlled by applied motor voltage and depended on the motor characteristics to operate at the desired speed. Most hoists were driven by direct current motors, either direct connected or driven through reduction gears. The motor D.C. power was supplied by motor generator sets converting the incoming A.C power to D.C. out power. Advances in solid state technology has replaced the M.G. set drives to solid state Thyristor Armature Supplies for D.C. motors and solid state variable frequency supplies for A.C. motors. The motor drive manufacturer’s developed feedback speed regulators to control the hoist motor speed. This presentation will investigate the problems encountered with mine hoist feedback speed regulation and explain the issues with controlling mine hoist speed.
