Overload monitoring circuit for synchronous electrical machine - measures phase lag or lead then detects jump in position of voltage vector to disconnect machine from supply

摘要

The circuit measures the phase lead in the case of a generator, or the phase lag in the case of a motor, relative to the network voltage, to detect a jump in the position of the voltage vector. A signal is supplied when such a jump is detected for interruption of the connection between the machine and the supply network. The circuit allows rapid detection of interruptions in the mains voltage and allows disconnection of the machine within an interval of less than 100 milliseconds.