The relay type NM20 can be used for protection of large size motors in MV systems.
For any grounded systems (solidly grounded, ungrounded or Petersen coil and/or resistance grounded) the protection can be used on feeders of any lenght.

Specifications

Key: standard optional alternative

Applications
• Motor
Protection functions
• Pt100 thermometric probes (26)
• Undervoltage (27)
• Positive seq. undervoltage (27V1)
• Reverse active overpower (32R)
• Phase undercurrent (37)
• Directional active underpower (37P)
• Loss of field (40)
• Negative sequence overcurrent (46)
• Phase reversal (47)
• Thermal image (49)
• Phase overcurrent (50/51)
• Residual overcurrent (50N/51N)
• Locked rotor (51LR(48)/14)
• Minimum power factor (55)
• Overvoltage (59)
• Residual overvoltage (59N)
• Negative seq. overvoltage (59V2)
• Maximum number of starting (66)
• Ground directional overcurrent (67N)
• Underfrequency & overfrequency (81U 81O)
• High impedance restricted earth fault (87NHIZ)
• Breaker failure (BF)
Monitoring and control functions
• CB diagnostic
• Cold Load Pickup (CLP)
• CTs monitoring (74CT)
• Digital Fault recording (DFR)
• Fault and event logging (SER & SFR)
• Logic selectivity
• Multiple setting profiles
• Programmable Logic Controller
• Self-test
• Trip circuit supervision (74TCS)
• VTs monitoring (74VT)
Hardware
• 2 binary inputs + 6 output relays + 8 LEDs
• Auxiliary power supply 110-230 Vac/dc
• Auxiliary power supply 24-48 Vac/dc
• Flush, projecting, projecting, rack, with separate MMI
• Network module with Ethernet FX port (optical fiber)
• Network module with Ethernet TX port (copper RJ45) + RS485 port
• Nominal current 1/5 A selectable by DIP-switch
• RS485 port (unavailable with Ethernet FX port)
• Standard CT amperometric inputs 1/5 A
Communication
• IEC 61850 Protocol
• Modbus RTU RS232 protocol
• Modbus RTU RS485 / IEC 870-5-103 / DNP3 protocol
• Modbus TCP/IP protocol (network board must be provided)