Abstract: D.C. motor control utilizing an input transformer with magnetic leakage and current control to allow power, whether generated occasionally or continuously from the motor (induced by load inertia and the like) to be smoothly returned back into the main A.C. power line, consistent with continuous smooth speed control (low form factor), low heating and low cost.

Abstract: Shunt motor field control for setting motor torque (and thereby controlling tension on a reeler or the like driven by the motor) comprising thyristor control gated by a comparator with a ramp-form voltage input compared to a reference level established by an operator setting of a potentiometer. The ramp-form voltage is generated by charging and discharging a capacitor and provides a spike voltage through the comparator when the reference level is exceeded. Means are provided to compensate potentiometer and capacitor tolerances to match potentiometers to the torque control setting range.