Interaction Between SCR Drives

In any motor control system consisting of more than one SCR phase-controlled variable voltage power supply, interaction can occur. Interaction within a system can result from several forms of interference: 1) high rates of current rise in the load di/dt which generate voltage wave fronts in excess of the SCRs withstand capability dv/dt; 2) transients generated in the system, coupling into the control, trigger, or gate circuits causing an SCR to conduct; 3) supply line distortion due to high reactive lines, causing degradation in system performance.