Protection Relay

Overview

The MRM4 is a protection relay which uses the latest Dual-Core-Processor Technology to provide precise and reliable protective functions and is very easy to operate. The MRM4 provides all necessary functions to protect low and medium voltage motors at all power levels. The protection functions are based on current measurement.
They supervise the motor start sequence (motor start), they detect a stall or locked rotor condition and they monitor the thermal condition of the motor. Overcurrent and earth overcurrent protection as well as unbalanced load protection are included in the protection package. The status and operation of the motor will also be monitored by means of the statistic and trend recorder. All important events and measuring values will be logged by means of the start, event, failure and disturbance recorder. The protection functions of the MRM4 have been adapted to comply with the requirements of the VDE‑AR‑N‑4110:2018.

Features

• Motor Protection Functions
• System Supervision Functions
• History Counter
• Logic equations for protection
• Total Counter
• Motor Start Recorder
• Statistic Recorder
• Additional Recorder
• Communication Options
• PC Tools
• Commissioning Support
• Time Synchronization
• IT Security
• Wattmetric Ground Fault Protection

Highlights

• 20 mA output (Type MRM4-2B)
• Long starting time for reduced voltage starts
• Emergency Start
• Incomplete Sequence
• Anti-backspin Time Delay
• Permitted number of cold starts
• Supervision of starts per hour
• Mechanical load shedding
• Zero speed indication via input
• Motor Stop Inputs
• External alarm and trip inputs

Details