DC motor thyristor control - has thyristor stages controlling motor through pulse width control stage

摘要

The accurate speed control of a d.c. motor (M) is achieved by thyristor switching stages (Th1, Th2, Th3) operating in a pulse width controlled mode. The output of a square wave generator is used to change the state of two counters. The values are compared with the output of an A/D converter operating on a variable signal proportional to speed. The decoded counter state combined with the comparator output are used to control the thyristor to maintain speed. The system also includes a capacitor (C1).