DC drive emergency braking circuit - has pulse controller supplying excitation current during emergency braking with extra controller for armature current

摘要

The braking circuit inserts one or more braking resistances into a motor armature circuit for emergency braking of a DC drive. The DC motor excitation current motor during the emergency braking is supplied by a pulse controller fed by the armature voltage. The excitation current is controlled so that in the whole speed range, the max. possible magnetic flux is set up in the magnetic circuit of motor. A braking current controller is provided to keep the current constant. The excitation current controller allows the armature voltage to be held constant in weakened magnetic field operation and the excitation current is held constant in the armature current controlled operation. USE/ADVANTAGE - For e.g. winding reel motor, and-or main drive of cold rolling mill. Inexpensive braking for high loads, guaranteeing full braking torque without use of auxiliary voltage sources. Motor is stopped as quick as possible on break-down, minimising possible damage to end product.