GE Multilin 469 Motor Protection System

GE Multilin 469 Motor Protection System

Product positioning and core values

The GE Multilin 469 motor protection system belongs to the SR relay family and is an integrated protection and management device designed specifically for medium and high voltage, large and medium-sized motors. It adopts a pull-out structure, balancing cost-effectiveness and industry-leading flexibility. Its core positioning is to provide comprehensive protection, precise control, simplified configuration, and advanced communication functions for medium and large three-phase motors (including high inertia, dual speed, and step-down starting motors), suitable for safe operation and management of motors and driving equipment in industrial scenarios. It can adapt to different motor characteristics through customized overload curves, single CT differential protection, and other functions. At the same time, with the help of motor parameter auto configurator, multi communication protocol compatibility, and other features, deployment and operation costs can be reduced, and equipment availability can be improved.

Core functions and protective features

（1） Comprehensive motor protection function

Hot model protection (core protection mechanism)

Multidimensional thermal management: integrating six core elements: overload curve (standard/customized/voltage dependent), negative sequence current bias (compensating for additional rotor heating), cold and hot safety stagnation ratio (defining the steady-state thermal capacity utilization rate of the motor), cooling time constant (distinguishing the heat dissipation rate during operation/shutdown), startup suppression and emergency restart (preventing startup when the thermal capacity is insufficient), RTD bias (combined with stator RTD temperature correction thermal model), updating the thermal capacity utilization rate (TCU) every 0.1 seconds, accurately simulating the actual thermal state of the motor.

Overload Curve Characteristics: Provides 15 standard overload curves (multiplier 1-15). The voltage dependent curve is suitable for high inertia loads and can dynamically adjust the thermal overload curve during the acceleration phase according to the system voltage, avoiding motor overheating caused by acceleration time exceeding the safe dead time.

Fault and abnormal working condition protection

Electrical fault protection: covering stator differential protection (supporting 6 CT external summation or 3 flux balanced CT connection, distinguishing the tripping threshold for startup/operation status), short circuit protection (removing the DC component of fault current, supporting secondary tripping backup when the fault is not cleared), grounding fault protection (supporting zero sequence CT, high sensitivity CT, phase CT residual connection, dual tripping/alarm threshold).

Abnormal working condition protection: including mechanical jamming (detecting rotor stalling, locking during startup), acceleration time monitoring (preventing abnormal long acceleration process), undervoltage/overvoltage (independent threshold during motor startup/operation phase, supporting locking in case of VT fuse failure), underfrequency (adjustable from 20-60Hz), over torque (adjustable from 1.0-999999.9 Nm/ft lb, only induction motor alarm), current imbalance (detecting negative sequence current ratio, including phase failure detection algorithm, dual trip/alarm threshold), etc.

Temperature and hardware protection

RTD Temperature Monitoring: Supports 12 programmable RTD inputs (compatible with Platinum 100, Nickel 100/120, Copper 10, etc.) to monitor stator, bearing, and ambient temperature. Each RTD includes three levels of thresholds: alarm, high alarm, and trip. Supports RTD trip voting and open/short circuit fault alarm.

Other hardware protections: including reverse power (to prevent motor from generating electricity due to reverse dragging), underpower (to detect load loss), abnormal power factor (synchronous motor out of step detection), limit on starting times/starting intervals (to prevent excessive starting losses), etc.

（2） Control and configuration functions

Flexible control mode: supports dual speed motor protection (independent overload curve), voltage reduction start monitoring (transition current/time control), frequency conversion filtering (suitable for accurate acquisition of analog signals in VFD scenarios), analog input differential calculation (dual drive system application), trip coil monitoring, etc., to meet the control requirements of different starting modes and operating scenarios.

Simplified configuration tool: equipped with a motor parameter auto configurator, complete parameter settings through a 6-step guided operation; Support on-site firmware and parameter upgrades, with optional conformal coatings for chemical corrosion/humid environments to enhance equipment adaptability.

Monitoring, measurement, and diagnostic capabilities

（1） High precision measurement function

Electrical parameter measurement: Real time monitoring of phase current, differential current, grounding current, average current, current imbalance, phase voltage/line voltage, average voltage, frequency, as well as active/reactive/apparent power, power factor, electrical energy (Wh/var), torque, demand value, etc., with measurement accuracy of ± 0.5% (when current<2 times CT) and ± 1% (when current>2 times CT).

Non electrical parameter measurement: 12 channel RTD temperature (range -50~250 ℃, accuracy ± 2 ℃), motor speed (100-7200 RPM, supporting inductive/Hall sensors), analog input (4-20mA/0-20mA/0-1mA, accuracy ± 1% of full range).

（2） Data recording and diagnosis

Event Recorder: Timestamp records system events, storing up to 256 events for easy tracing of fault causes.

Waveform capture: Record 10 waveforms (Ia/Ib/Ic/IG/Diffa/Diffb/Diffc/Va/Vb/Vc) during tripping, with 12 samples per cycle and a total of 64 cycles of data, supporting fault waveform analysis.

Advanced diagnosis: optional rotor bar breakage detection function, continuously monitoring the health status of the rotor through motor current signal analysis (MCSA), early warning of rotor faults (such as starting torque drop, overload, bearing wear), supporting programmable alarms, and achieving predictive maintenance.

Simulation testing: Pre trip and fault conditions (current, voltage, frequency, RTD temperature, etc.) can be simulated without external input, simplifying the debugging and commissioning process.

Hardware specifications and interface configuration

（1） Input/output interface

Current and voltage input

Current input: 2 sets of three-phase CT inputs (phase current CT supports 1A/5A secondary side, specified when ordering; Differential CT field programmable 1A/5A), 2-channel grounded CT input (standard CT supports 1A/5A, high-sensitivity CT supports 50:0.025A), CT withstand capability up to 80 times rated current for 1 second, 40 times rated current for 2 seconds, and 3 times rated current for continuous operation.

Voltage input: Three phase VT input (supporting star/delta connections, full range 273V AC, accuracy ± 0.5% full range, frequency range 20-120Hz), supporting VT fuse fault detection.

Digital and Analog Interface

Digital input: 9-way optically isolated input (5 pre-defined: starter status, emergency restart, remote reset, parameter access, test switch; 4 assignable: remote trip/alarm, speed switch, vibration switch, pressure switch, etc.), supports dry contact or NPN collector input.

Analog input/output: 4-channel configurable analog input (supports 4-20mA/0-20mA/0-1mA, input impedance 226 Ω± 10%), 4-channel configurable analog output (specify 4-20mA or 0-1mA when ordering, accuracy ± 1% of full scale, 4-20mA maximum load 1200 Ω, 0-1mA maximum load 10k Ω).

Output relays: 6 sets of Form-C output relays (4 sets of non fault safe type, can be assigned with trip/alarm function; 1 set of non fault safe type start interlock relay; 1 set of fault safe type service relay, indicating loss of control power or internal fault), supporting interlock function, with a maximum rated contact value of 10A continuous (DC 30V 300W, AC 250V 2770VA).

（2） Human Computer Interaction and Communication

Local interaction: 40 character display screen (displaying parameters, actual values, fault/alarm information), numeric keypad (parameter input and navigation), 22 LED indicator lights (system status, motor status, output relay status), supporting 20 user-defined default messages.

Communication capability: Comes standard with 3 serial ports (front RS232 for debugging, rear 2 RS485 for remote communication), optional 10BaseT Ethernet and DeviceNet ports; Supports Modbus RTU (serial port) and Modbus TCP/IP (Ethernet port), multiple ports can communicate simultaneously, and Ethernet can be connected to local/wide area networks, replacing multi drop wired networks and reducing operation and maintenance costs.

Software and Operations Support

（1） EnerVista software suite

Configuration and Debugging Tools: Provides automatic configuration of motor parameters, firmware upgrades, parameter backup/recovery functions, supports waveform and event viewing, and simplifies fault diagnosis.

Monitoring and integration tools: Viewpoint Monitoring provides plug and play device monitoring, single line diagram monitoring and control, alarm annunitor, trend reports; EnerVista integrator includes OPC/DDE servers, Multilin drivers, and supports seamless integration with existing HMI/SCADA systems.

Maintenance tool: Viewpoint Maintenance provides parameter audit tracking reports, equipment health reports, and comprehensive fault diagnosis to enhance operational security and efficiency.

（2） Pull out structure and retrofit support

Pull out design: easy to replace quickly, reduces downtime, supports wire lead sealing to prevent unauthorized removal.

Retrofit upgrade: With the 8 series Retrofit kit, old SR 469 relays can be upgraded to 869 motor protection systems without modifying existing panel openings, rewiring, or changing drawings. The upgrade process only requires 3 steps (updating parameter files, removing old relays, plug-in reconnection) and can be completed in as fast as 21 minutes, reducing upgrade costs and system downtime.

Technical specifications and environmental adaptability

（1） Key technical parameters

Category specification details

Current measurement CT primary side 1-5000A, secondary side 1A/5A; Accuracy: ± 0.5% for current<2 times CT, ± 1% for current>2 times CT

Voltage measurement VT ratio 1.00-15.00:1, secondary side full range 273V AC; Accuracy ± 0.5% of full scale

RTD measurement supports 4 types of RTD, with a range of -50~250 ℃ and an accuracy of ± 2 ℃. Each channel has a 3-level threshold (alarm/high alarm/trip)

Communication speed serial port baud rate 300-19200 bps, Ethernet 10Mbps

Low range of power supply: DC 24-60V/AC 20-48V; High range: DC 90-300V/AC 70-265V, power 45VA (maximum)

（2） Environment and Compliance

Environmental adaptability: working temperature -40~+60 ℃, storage/transportation temperature -40~+80 ℃, humidity 0-95% (55 ℃ without condensation), protection level IP40 (front)/IP20 (back), pollution level 2.

Compliance certification: Compliant with EN60255 series, IEC 61000 series, UL508/UL1053, cULus and other standards, passed ISO9001 quality system certification, CE certification (EN60255-5/27, EN61010-1, etc.).

Ordering and configuration options

（1） Basic models and core options

Basic unit: The model starts with "469", and subsequent codes distinguish key configurations:

CT secondary side: P1 (1A), P5 (5A);

Control power supply: LO (low range: DC24-60V/AC20-48V), HI (high range: DC90-300V/AC70-265V);

Analog output: A1 (0-1mA), A20 (4-20mA);

Extended functions: D (DeviceNet), E (Enhanced Front Panel), T (Enhanced Front Panel+Ethernet), H (Anti harsh Environment Coating).

（2） Optional accessories

Including pull-out handle (with lead seal), RTD sensor, CT/VT of different specifications, Retrofit upgrade kit (including terminal block and depth reduction ring compatible with old SR relays), EnerVista software kit, etc., can be flexibly selected according to on-site needs.