Project Description

SEL-749M Motor Relay

SEL-749M Motor Relay

Get comprehensive motor protection and SEL-exclusive reporting and trending that save you money in your industrial motor plant and processes. The SEL-749M uses the latest enhancements in the SEL-patented thermal overload model to accurately track the heating effects of operating and cyclic overload currents. The relay offers all basic motor protection features, including short circuit, load loss, load jam, and frequent starting protection as well as imbalance current and phase-reversal protection. Add optional voltage, I/O, and communications capabilities to build the SEL-749M that is just right for your application.

Functional Overview

14 Speed Switch
27 Undervoltage
37 Undercurrent, Underpower
38 Bearing Temperature
46 Current Unbalance
47 Phase Reversal
48 Incomplete Sequence/Load Jam
49 Motor Thermal Overload
49T Temp, Alarms & Trips
50 (P,G) Overcurrent (Phase, Residual)
50N Neutral Overcurrent
55 Power Factor
59 Overvoltage
66 Starts-Per-Hour
LC/71 Load Control
81 (O,U) Over-/Underfrequency
DFR Event Reports, Motor Start Reports and Start Trending
SER Sequential Events Recorder
VAR Reactive Power

* Optional
** Select when Ordering


Front- and Rear-Panel Diagrams

SEL-749M Front Panel SEL-749M Rear Panel
Front Rear


True Temperature-Based Thermal Overload Protection

Eliminate false tripping, especially during cyclic overload operations.Release motor capability unavailable with traditional overload relays.

Comprehensive Start Reports and Trends

Track motor performance during the critical starting period with complete motor start reports and 30-day average motor start trending.Only SEL offers this valuable tool for tracking motor performance.

Option Cards for Added Functionality

Customize the relay for your particular protection and control applications. Select optional voltage, I/O, and communications cards.

Complete Reporting for Increased Operating Time

Troubleshoot motor/process problems using valuable, stored informa-tion about motors and processes from motor statistics, oscillograms,event reports, and sequential events records.

Extensive Communications and Software Capabilities

Communicate seamlessly with built-in SEL ASCII and optional Modbusand DeviceNet protocols. Quickly and easily set the SEL-749M with theincluded, Windows®-based ACSELERATOR®SEL-5030 Software.

Compact, Ruggedized Hardware

Mount in any motor control center with this UL/IEC switchgear-rated,short-mounting-depth relay



749M 701 849
Induction Motor Protection
Synchronous Motor Protection +
Feeder Protection
Breaker Failure Protection f f
Equipment Thermal Monitoring + + +
27/59 Under-/Overvoltage + + +
32/37 Directional/Underpower Elements + + + +
40 Loss-of-Field +
46 Current Unbalance
47 Phase Reversal
49 Thermal
50 (P,N,G) Overcurrent (Phase, Neutral, Ground)
50Q Negative-Sequence Overcurrent
51 (N,G) Time-Overcurrent (Neutral, Ground)
51 (P,Q) Time-Overcurrent (Phase, Neg. Seq.)
55 Power Factor + +
60 Loss-of-Potential + f f +
78 Out-of-Step +
81 Over-/Underfrequency + +
87 Current Differential +
Arc-Flash Detection +
Separate Neutral Overcurrent
Broken Rotor Bar Detection +
SELogic Control Equations/Remote Control Switches
Nonvolatile Latch Control Switches
Multiple Settings Groups
Breaker Wear Monitor
Event Report (Multicycle Data)/Sequential Events Recorder
Demand Meter
Load Profile Report
RTD (Resistance Temperature Detector) Inputs + + +
Ethernet +
IEC 61850 + +
Simple Network Time Protocol (SNTP)
Modbus TCP
Modbus RTU Outstation
Synchrophasors With IEEE C37.118 Protocol
Mirrored Bits Communications
DeviceNet + +
Accepts Wye or Open-Delta Voltage Transformers + + +
Standard Feature
+ Model Option
f This function may be created using settings

Product Literature