The SQZ3 relay performs the following monitoring functions in three-phase networks at 400 V AC for phase sequence, phase failure and minimum voltage (adjustable, max. 70% of Vn). If one of the three faults is detected, the output relay (safety switch contact) intervenes with a delay adjustable from 2 to 20 s only at minimum voltage and controls the following: Acoustic alarms, motor control contactors, circuit breakers with coils
