RNPP-311M is designed for:

• Monitoring acceptable voltage levels
• Checking the correct phase sequence and absence of phase sticking
• Ensuring phase continuity and voltage symmetry in the network (phase imbalance)
• Disconnecting the load during poor network voltage conditions
• Monitoring the network voltage after load disconnection and automatically reconnecting it once the voltage parameters are restored
• Indicating fault conditions and displaying voltage availability on each phase
• RNPP-311M monitors the neutral indirectly
• The device allows parameter adjustments (voltage trip thresholds, automatic restart delay (AR), and protection trip delay), network voltage selection (400 V or 415 V), and the configuration of protective functions
• After restoring network voltage parameters, the relay automatically reconnects the load after the set AR delay

RNPP-311M can operate in the following modes:

• Minimum/Maximum Voltage Monitoring
• Minimum Voltage Monitoring
• Maximum Voltage Monitoring
• Phase Availability Monitoring
• Monitoring for incorrect phase sequence and phase sticking
• Phase Imbalance Monitoring

Phase Availability Monitoring remains active in all operating modes. In any mode, the device trips if a phase is lost or the voltage drops below 100 V on one or more phases for a fixed duration of 0.2 seconds.

Output and Contacts

The device has two groups of independent changeover contacts (1-2-3, 4-5-6). In the "COLD STATE" (device unpowered or not connected), contacts 1-2 (4-5) are closed, while contacts 2-3 (5-6) are open.

When the load relay trips, the load is disconnected by breaking the power circuit of the magnetic starter coil via contacts 1-2 (4-5). Exception: in the "Maximum Voltage Monitoring" mode, the relay operates with reverse switching logic.

Advantages:

• Simple configuration
• Connection via a magnetic starter
• Compact size
• Changeover contacts for versatile use

Applications:

• Monitoring phase and line-to-line voltages in three-phase networks
• Protecting three-phase or, in some cases, single-phase equipment from faults, such as voltage anomalies, incorrect phase sequence, phase sticking, phase loss, and voltage asymmetry
• Ideal for protecting refrigeration and ventilation systems

Key Features:

• Monitoring allowable voltage levels
• Phase sequence monitoring and prevention of phase sticking
• Ensuring phase continuity and voltage symmetry
• Disconnecting the load by breaking the power circuit of the magnetic starter coil under fault conditions
• Monitoring network voltage quality after load disconnection and automatically reconnecting the load once voltage parameters are restored
• Ability to disable specific protective functions