SEL-849 Хөдөлгүүрийн удирдлагын реле

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 128 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.

Multiple Applications—The SEL-849 Relay supports pumping applications for water, chemicals, and petroleum; air-based applications, including fans, blowers, air handlers, and compressors; chiller applications, such as compressors and air conditioning; and applications involving bulk materials, such as conveyors, crushers, screeners, feeders, augers, and bucket elevators. The SEL-849 can be configured as a motor, VFD motor, or feeder protection relay.

Low-voltage Feeder Protection—The SEL-849 includes a full set of instantaneous time and overcurrent elements that provide advanced low-voltage feeder protection:

  • Overcurrent
  • Voltage
  • Directional Power

Motor Control Centers (MCCs)—A primary application for the SEL-849 is for overload and arc-flash protection of MCCs. In this application, the SEL-849 operates the contactor, controlling the start and stop of the motor. The SEL-849 receives start/stop commands with IEC 61850 and Modbus protocols, contact inputs, or the remote HMI Start/Stop pushbuttons.