Fast response thyristor drive for DC motors - has limiting chokes connected to anti:parallel thyristor pair forming full:wave rectifier circuit output to second motor terminal

摘要

The fast response thyristor drive circuit for DC motors consists of a mains transformer (5) with secondary centre tap connected to one side of the motor (9) and chokes connected to each side of the secondary (6, 7). Each choke is connected to a pair of anti-parallel-connected thyristors (2) forming a full-wave rectifier circuit whose output (8) is connected to the second motor terminal. Each thyristor gate is connected to a firing angle control unit (11) and associated control amplifier (12). The amplifier input is provided by a control voltage amplifier (13) driven from a speed control input (14). These two stages are also controlled by a voltage derived from a tachometer directly coupled to the motor. Circuit current-limiting is largely provided by the impedance due to the choke coils.