Magnetic-amplifier control of D-C motors

ALTHOUGH considerable work has been done on the operation of adjustable-speed d-c motors with armature power supplied by thyratrons1 and by metallic rectifiers controlled with adjustable transformers,2,3 there is little information available on the use of magnetic amplifiers for this purpose. For this reason, an analytical and experimental study was made of the steady-state operation of a d-c motor with armature power supplied through metallic rectifiers and controlled by saturable reactors or magnetic amplifiers. More specifically, the speed-torque characteristics of the motor were determined for the various control methods and, in particular, the effectiveness of simple feedback connections and the use of external armature-circuit inductance was ascertained in improving the speed regulation.