Electronic logic control for DC traction - with servo driven current regulator and modulated smooth adjustment for braking

摘要

The DC traction is controlled by a stepping switch over a series of resistances, with the stepping operated by a servo driven cam. A logic control compares the actual motor current with a reference value and adjusts the current accordingly. In order to provide a smooth control the braking effect is smoothed. If the reference current is greater than the actual current then the servo increases the current directly. If the reference current is lower than the servo action is modulated to smoothly change the motor current and prevent sudden torque changes.