Selectron Voltage Monitoring Relay

Versions for 1- and 3-phase systems. Under- and overvoltage monitoring, window function. 3-phase devices with adjustable phase sequence, phase failure and asymmetry monitoring (not adjustable in SU31D and IU11D). Operation with or without neutral conductor monitoring (except in IU11D). Versions with and without adjustable triggering delay. Design, 17.5 mm: 1 changeover contact, plug-in and 35 mm designs: 2 changeover contacts.