Abstract: A drive system for a hoist-pulldown linkage of a blast hole drill employs a variable speed electric motor and a variable ratio coupling between the motor and the hoist-pulldown linkage. A first regulator actuates the electric motor for high torque operation when the ratio of the coupling is low. A second regulator means activates the electric motor for low torque operation when the ratio of the coupling is high. Transfer in coupling ratio is coordinated with change between regulators. The first regulator means is a voltage regulator with a current spillover limit. The second regulator is a voltage regulator with an adjustable pulldown force limit with means to select the rotational speed reference of the motor.