The Application of Solid-State Logic to the Control of Synchronous Motors with Collector Rings and Brushes for Separate Excitation

Synchronous motors must be designed to have torque-speed characteristics which will match the load they are to accelerate. Motor designers have several parameters at their disposal for shaping the torque-speed curve of the motor, perhaps even more than the induction-motor designer. Maximum utilization of this available motor torque may, however, depend upon the effectiveness of the control apparatus associated with the motor for starting, synchronizing, and desynchronizing. Lack of effective control can result in the motor failing to pull in the load, or it can result in large power swings which can disturb the electrical system, damage the driven load, or damage the motor.