(1) Overload protection: the soft starter introduces a current control loop that tracks motor-current changes at all times. With an overload-current setting and inverse-time control, it provides overload protection — when the motor overloads, it switches off the thyristors and issues an alarm signal.
(2) Phase-loss protection: during operation the soft starter continuously monitors the three-phase line currents; as soon as a current interruption occurs, it responds with phase-loss protection.
(3) Overheat protection: an internal thermal relay monitors the thyristor heatsink temperature; once the heatsink exceeds the allowed value, the soft starter automatically switches off the thyristors and issues an alarm.
(4) Other functions: through combinations of electronic circuits, various additional interlock protections can be implemented in the system.
