RNPP-301 voltage relay is designed to protect three-phase consumers from the main types of electrical network failures, such as:

• Exceeding or falling below the permissible voltage thresholds.
• Phase sequence violations and phase sticking.
• Loss of phase and symmetry of the network voltage.

The device monitors the key parameters of the electrical network and disconnects the load when they deviate beyond acceptable limits.
RNPP-301 also monitors the condition of the power contacts of the external magnetic starter before and after the load is switched on, ensuring their integrity (detecting burning or sticking).

Indicators are displayed on the front panel of the device, which display:

• The presence of voltage in the network.
• The load status (on or off).
• The type of fault that has occurred.

Six knobs on the front panel allow the user to make adjustments:

• Trip threshold for the maximum permissible voltage level.
• Trip threshold for the minimum permissible voltage level.
• Permissible phase imbalance threshold.
• Trip time delay for disconnecting the load due to a critical voltage drop.
• Trip time delay for other types of network faults.
• Time delay for reconnecting the load after the network parameters are restored.

The device can operate in phase or line voltage monitoring mode (user selectable).

Advantages:

• Connection through a magnetic starter
• Monitoring the state of the magnetic starter's power contacts before and after load activation.
• Simple configuration.
• Advanced trip parameter settings, including separate adjustment for Umin and Umax.

Application Area:

• Monitoring phase and line voltages in a three-phase network.
• Protecting three-phase or, in some cases, single-phase equipment from faults in a three-phase network, such as overvoltage, incorrect phase sequence, phase sticking, loss of phase, or voltage imbalance.

Key Features:

• Monitoring the permissible operating phase/line voltage levels.
• Monitoring correct phase sequence and absence of phase sticking.
• Monitoring phase presence and symmetry of network voltage.
• Monitoring the condition of the magnetic starter's power contacts before and after load activation.
• Disconnecting the load by breaking the magnetic starter coil circuit when trip conditions are met, with a user-set trip delay time (Tsr).
• Monitoring network voltage quality after load disconnection and automatic reconnection once parameters are restored, with a user-set automatic reconnection delay time (Tvkl).
• Visual indication of all types of network voltage faults and magnetic starter contact switching failures.