Multifunctional three phase voltage monitoring relay RNPP-302M1 is designed to protect three-phase consumers from major electrical network faults, including:

• Voltage exceeding permissible thresholds
• Phase sequence errors and phase sticking
• Phase failure and voltage asymmetry

RNPP-302M1 measures the actual phase (line-to-line) voltages in networks with grounded or isolated neutrals and controls the coil of an external magnetic starter, which switches the load power circuit.

The relay also monitors the state of the power contacts of the external magnetic starter before and after load activation, ensuring their reliability (e.g., detecting contact burning or sticking). 

The device operates in four independent modes:

• Phase-failure relay (voltage-level control disabled)
• Minimum voltage relay
• Maximum voltage relay
• Voltage relay

RNPP-302M1 displays the actual phase (line-to-line) voltage, voltage fault conditions, the state of the load relay (on/off), and the type of fault.

Advantages:

• Connection via magnetic starter
• Monitoring the state of the starter's power contacts before and after load activation
• Segment display
• Support for networks with grounded or isolated neutrals
• Operation in four independent modes

Applications:

• Monitoring phase and line-to-line voltages in a three-phase network
• Protecting three-phase or, in some cases, single-phase equipment from faults in three-phase networks, such as voltage anomalies, incorrect phase sequencing, phase sticking, phase failure, and voltage asymmetry
• Protecting three-phase equipment in three-phase networks without a neutral wire

Key Features:

• Monitoring the permissible levels of actual phase/line-to-line voltage
• Phase sequence and phase sticking control
• Monitoring phase integrity and network voltage symmetry
• Monitoring the state of magnetic starter power contacts before and after load activation
• Load disconnection by opening the power circuit of the magnetic starter coil in response to fault conditions, with user-defined trip delay
• Monitoring network voltage quality after load disconnection and automatic load reconnection once voltage parameters are restored, with user-defined automatic restart time
• Visual indication of all types of network voltage faults and magnetic starter contact switching failures

Wiring diagram: