Digital monitoring relay for 3-phase voltage with N-conductor Autom. phase sequence correction Phase failure 3 x 90 to 400 V 50 to 60 Hz AC Undervoltage and overvoltage 90-400 V Hysteresis 1-20 V OFF delay 0-20 s Asymmetry 0-20% 1 CO for phase correction 1 CO for line supply faults Spring-type connection system