Externally-excited DC motor speed control for crane - prevents armature circuit overload when motor runs above basic speed (RU 14.9.76)

摘要

The speed control is applied to an externally-excited DC motor for a crane. It releases a signal when a limit is exceeded when the motor is running at speeds above its basic speed and thereby prevents the armature circuit from being overloaded. This signal prevents the speed increasing further. When the load, on the crane is being lowered and the motor is driven by the load, the reference generator's (11) acceleration signal is interrupted at a lower armature current than the preset value. When the load is being raised this interruption takes place at a higher armature current.