GE SR469-P5-LO-A20 SR469 Motor Management Relay Unit

Module Feature

SR469-P5-LO-A20 belongs to GE Multilin SR469 series draw-out motor management relay.

This variant supports low ohm RTD sensors for winding and bearing temperature monitoring. It integrates comprehensive motor protection functions including thermal overload, negative sequence unbalance, locked rotor, instantaneous short circuit and ground fault. The relay provides real-time electrical metering, fault waveform capture and event timestamp storage for post-fault analysis. Draw-out design enables quick replacement without altering field wiring. It is widely used as maintenance spare in power plants, chemical plants and oil & gas facilities for medium voltage motor feeders.

Working principle

The relay continuously samples CT secondary current, PT voltage and RTD temperature signals.

Onboard firmware runs thermal simulation algorithm to track motor heat accumulation. Once measured value exceeds protection setpoint, the relay activates trip or alarm dry contact output to de-energize the motor. Real-time measurement data, alarm records and fault waveforms can be retrieved through serial communication port to SCADA or engineering workstation. It also supports start inhibit and interlock logic for process safety control.

Onboard components

Signal acquisition circuit, main processing chip, non-volatile memory for fault records, low ohm RTD measurement module, local LCD display, status LED bank, multi-form-C relay outputs, communication interface and draw-out chassis assembly.

LED indicators

Front panel LEDs indicate power, run, alarm and trip status; local LCD shows measured values, setting groups and fault codes.

Hardware self‑diagnosis

Internal supervision circuit monitors CT continuity, RTD wire break, board power supply and communication channel health. Configuration and fault analysis are completed by GE EnerVista software.

Programming software

EnerVista, used for protection curve setup, thermal model configuration, communication address assignment, waveform and event log download.

Electrical & Process Parameters

Model:SR469-P5-LO-A20 Brand:GE Multilin Device type:SR469 motor management protection relay Function:Multi-element motor protection, low ohm RTD temperature monitoring, metering and fault recording for medium voltage motors

Mechanical & Structure

Mounting:Draw-out installation inside motor control cabinet Protection class:IP40 (front panel) Housing:Flame retardant reinforced plastic

Environmental

Operating temperature:-40℃ ~ +70℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non‑condensing

Certification:CE, UL Status:Original GE motor protection spare

Installation

Cut off CT circuit and control power before replacement.

Insert relay unit into draw-out base, connect CT, PT, RTD and control wiring, download protection setting file, test trip logic and communication link after commissioning.

Interface

CT/PT signal terminals, low ohm RTD input terminals, alarm and trip relay output terminals, RS485 communication port.

Diagnostic

Overload trip: Sustained overloading or degraded motor cooling. RTD fault alarm: Sensor open circuit or wiring failure. CT fault alarm: Secondary circuit open or shorted. Communication offline: Cable damage or Modbus address conflict.

Product Brief

SR469-P5-LO-A20 relay, GE Multilin SR469 draw-out motor management relay with low ohm RTD input for medium voltage motor protection cabinet replacement.