Motor Management Relay
The SEL-849 Relay offers current-, voltage-, and thermal-based motor protection; arc-flash detection; and power metering. It also provides all basic motor protection features, including protection for the following conditions:
- Short circuit
- Load loss
- Load jam
- Frequent starting
- Imbalanced current
- Phase reversal
The SEL-849 installs easily inside a motor control center (MCC). The optional SEL-3421 and SEL-3422 Motor Relay HMIs (human-machine interfaces) install on the front of the MCC.
Motor Protection—Protect low- or medium-voltage three-phase induction and variable-frequency drive (VFD)-fed motors with an enhanced thermal model. Connect an external core-balanced current transformer (CBCT) to obtain sensitive ground-fault detection in high-impedance grounded systems.
Arc-Flash Mitigation—Improve worker safety using the SEL-849 Motor Management Relay’s built-in arc-flash detection (AFD). The AFD, supervised by overcurrent elements, delivers secure, reliable, and fast-acting arc-flash protection.
Feeder Protection—Configure flexible instantaneous and time overcurrent elements to protect feeder circuits.
Direct Connection—Connect up to 690 V to the optional voltage inputs and up to 256 FLA (full-load amperes) through the built-in CT primary circuits. Use external instrument transformers for higher voltages or currents.
Optional Human-Machine Interface (HMI)—Install SEL-849 Relays in motor control center (MCC) buckets, and connect the optional display modules (SEL-3421 or SEL-3422) outside the MCC for secure and safe relay access.
Metering and Monitoring—Analyze SER reports and oscillographic event reports for rapid commissioning, testing, and post-fault diagnostics. Reduce separately mounted metering/monitoring devices by taking advantage of the SEL-849 Relay’s motor start report, motor start trending, motor operating statistics, energy metering, minimum/maximum metering, and demand metering features.
Integration—Select from a variety of communications ports and protocols—IEC 61850, Modbus, SEL ASCII, and SNTP—to integrate SEL-849 Relays into supervisory or coordinated protection and control systems.