GE Multilin SR489-P5-HI-A20-E-H – Motor Management Relay for Reliable Protection of Medium and Large AC Motors

The GE Multilin SR489 series is a proven motor management relay that’s typically installed on critical pumps, fans, compressors, and conveyors where a clean trip and fast diagnostics matter. The SR489-P5-HI-A20-E-H variant combines 5 A CT inputs (P5) with a universal high-range power supply (HI), 4–20 mA analog output capability (A20), and Ethernet-enabled communications (-E). From my experience, this configuration hits the sweet spot for plant standardization—easy to retrofit, straightforward to maintain, and solid on day-to-day protection.

Company’s Order Placement Process and Guarantees

• Quotation & confirmation: We confirm the exact option string (SR489-P5-HI-A20-E-H) and firmware needs before issuing PI.
• Payment terms: 50% advance payment; full payment prior to delivery.
• Lead time: 1 week if in stock; no more than one month at the latest.
• Logistics: Express via FedEx, UPS, or DHL, packed for sensitive electronics.
• Warranty: 365 days warranty; devices are function-tested before shipment.

Key Features

• 5 A CT inputs (P5): Suits standard protection-class CTs; ideal for brownfield upgrades where 5 A secondaries are already installed.
• Universal power supply (HI): Typically 90–300 VDC or 70–265 VAC, 50/60 Hz, making spares simpler across different MCC lineups.
• 4–20 mA analog outputs (A20): Feeds DCS/PLC with live motor load, thermal capacity, or other key metrics; usually two channels are available on A20 builds.
• Ethernet connectivity (-E): Adds Ethernet-based comms (commonly Modbus TCP) for centralized monitoring; RS485 Modbus RTU remains available in most cases.
• Comprehensive motor protection: Thermal model, overload, jam/stall, ground fault (residual), current unbalance, undercurrent, load loss, start/acceleration supervision.
• RTD temperature inputs: Supports multiple RTDs for stator, bearing, and ambient temperature supervision—vital for large-frame motors.
• Event records & diagnostics: Time-stamped events and alarms help you pinpoint root causes quicker after a trip.
• Draw-out case: One thing I appreciate is the withdrawable chassis—speeds up maintenance and keeps wiring intact.
• Local HMI & metering: Clear on-front indications for motor load, thermal capacity, and trip cause; operators typically like the fast visibility.

Technical Specifications

Typical Applications

Useful on medium-voltage and large low-voltage motors driving cooling water pumps, induced draft fans, belt conveyors, compressors, and mixer drives. One maintenance manager told us the SR489 reduced nuisance trips during heavy starts, mainly thanks to the thermal model and start supervision being easier to tune than their older electromechanical scheme.

Related or Supporting Products

• GE Multilin SR469: Adds voltage-based functions and advanced motor protection; a common alternative when voltage metering is required.
• GE Multilin 369: Cost-effective motor relay for LV/MV motors with essential protections and metering.
• GE Multilin SR650 / SR750: Newer-generation relays with modern comms and cybersecurity features; preferred for greenfield projects.
• 5 A Protection CTs (Class 5P/10P): Match the P5 input; select knee-point and burden to support ground-fault sensitivity.
• Pt100 RTDs (2- or 3-wire): For stator and bearing temperature monitoring; ensure consistent wiring practices to reduce drift.
• RS485–Ethernet gateways: When a mix of legacy Modbus RTU and Ethernet SCADA is present; simplifies control system integration.
• Panel accessories: Cutout gasket, test plug, and terminal label kits for clean commissioning and easier servicing.

Installation & Maintenance

• Panel & environment: Mount in a clean, ventilated enclosure meeting typical MCC standards (IP54 or better if dusty). Allow space for rear wiring bend radius and heat dissipation.
• Power & grounding: Use a clean, fused auxiliary supply. Bond shield drains at one end only; keep relay ground solid to avoid measurement noise.
• CT & RTD wiring: Observe CT polarity (S1/S2) and short CT secondaries during maintenance. For RTDs, 3‑wire is preferred for accuracy; route sensor wiring away from power cables.
• Communications: For RS485, use shielded twisted pair, 120 Ω terminations at the ends, and proper biasing. On Ethernet builds (-E), segregate control and corporate networks where possible.
• Settings & testing: Validate protection curves against motor nameplate data; run primary or secondary injection where practical. Keep a golden settings file backed up.
• Routine care: Annually check terminals, clean filters/vents, review event logs for pattern changes, and apply firmware updates if applicable and approved by site policy.

Quality & Certifications

• CE compliant; UL/cUL or CSA certifications are typically available for GE Multilin SR series.
• Manufactured under ISO 9001 quality systems.
• RoHS compliance may vary by production date; we can verify against your site’s environmental requirements.
• Warranty: 365 days from our side; factory warranty terms are commonly 12 months—confirmable by serial and build sheet.

You might notice the option string alignment (P5, HI, A20, E) makes this unit a strong drop-in for many installed bases. If your site has mixed 1 A/5 A CTs or needs specific comms mappings, share a snapshot of the existing relay’s nameplate, and we’ll match the build and settings profile to avoid surprises during commissioning.