Description
Product Introduction & Engineering Value
Swapping a protection relay on a low-voltage battery back-up system can quickly derail a shift if you order the wrong control power rating. Installing a standard high-voltage relay into a 24VDC control cabinet leaves you with a dead display and zero motor diagnostics.
The GE Multilin 369-LO-0-M-0-0-0-E directly addresses this specification. Its “LO” power supply handles 20–60 VDC or 20–48 VAC auxiliary power buses, making it the primary choice for remote off-grid, solar-backed, or DC station battery panels. Equipped with the “M” metering package and an “E” Ethernet interface, it streams full three-phase power telemetry directly across Modbus TCP/IP networks without requiring separate transducer hardware.
Technical Specifications
| Parameter | Specification |
| Control Voltage (LO) | 20 to 60 VDC / 20 to 48 VAC (45–66 Hz) |
| RTD Channels (0) | None Installed (Internal RTD Card Omitted) |
| Metering Package (M) | Real-time Volts, kW, kvar, kVA, PF, Hz, MWhr + 3 Configurable Analog Outputs |
| Communication Ports | Rear RJ45 Ethernet (E Option – Modbus TCP/IP), 3x Rear RS485 (Modbus RTU), 1x Front RS232 |
| Phase/Ground CT Inputs | 1 A or 5 A Secondary (Field Selectable) / Variable Ground CT Input |
| Output Contacts | 4 Form-C Assignable Relays (Trip, Alarm, Aux 1, Aux 2) |
| Enclosure Protection | NEMA 12 / IP54 Front Panel Interface |
| Transient Immunity | Meets IEEE C37.90.1 / IEC 60255 Standards |
| Operating Temperature | -20°C to +60°C (-4°F to 140°F) |
| Conformal Coating (0) | Standard Industrial Coating |
Field Application & The “Trench” Experience
A solar-assisted off-grid booster station in West Texas suffered intermittent control lockouts because an older relay required a 120VAC inverter supply that repeatedly collapsed under high ambient heat. The plant engineering team redesigned the cabinet to run directly off the station’s native 24VDC battery bank. They dropped in a GE 369-LO-0-M-0-0-0-E relay. By running directly on 24VDC power, the unit eliminated the fragile inverter step, retained full motor overload protection, and continuously pushed line voltage and power factor data back to the central SCADA center via its rear Ethernet port.
Specific Field Applications
- Off-Grid Station Battery Systems: Operates directly from 24VDC or 48VDC station batteries for reliable trip execution during complete AC grid blackouts.
- Pipeline Intermediate Pumping Stations: Uses the “M” option metering package to balance real-time pump power consumption (kW/kVA) without extra external transducers.
- Remote Water Lift Stations: Connects directly into regional Modbus TCP networks via the “E” RJ45 port for continuous remote motor status logging.
Transparency SOP: QA & Testing
- Low-Voltage Power Supply Sweep: Bench testing the “LO” power card across its full voltage range (18 VDC up to 65 VDC) to verify internal DC-DC converter startup and hold-up times.
- Metering Channel Injection: Injecting balanced and unbalanced 3-phase AC voltage and current via a secondary injection set to confirm readout accuracy for kW, kVA, and power factor.
- Ethernet Communications Verification: Continuous ping testing, packet loss analysis, and setpoint read/write stress-testing over the rear RJ45 Ethernet port.
- Contact & Input Testing: Triggering all 4 Form-C output relays under simulated load conditions and verifying optical isolation on all discrete inputs.
- Thermal Endurance Cycle: 12-hour thermal chamber burn-in at elevated ambient temperatures to identify any potential component solder faults before field shipment.
- 369-LO-0-M-0-0-0-E
- 369-LO-0-M-0-0-0-E
The Veteran’s Tech Trap Guide
⚠️ Do Not Hook Up to 120VAC Station Power: Connecting a 120VAC or 230VAC control bus to a 369-LO relay will instantly blow the internal metal-oxide varistors (MOVs) and destroy the “LO” power supply card. Always verify terminal A1-A2 supply voltage with a multimeter before landing wires.
PRO TIP: The “0” option in the RTD slot means this specific unit has no onboard RTD card. If your existing setup uses 100Ω Pt or 120Ω Ni stator temperature sensors, you must install an external RRTD module (Remote RTD module) and link it to the 369-LO via an RS485 serial port.
⚠️ Ethernet Link Speed Restrictions: The “E” option Ethernet interface operates on standard 10/100 Mbps copper links. Connecting it directly to a modern Gigabit-only managed switch port without enabling autonegotiation or forcing 100 Mbps full-duplex can cause lost packets or offline link alarms.
Dynamic FAQ
Q: What is the primary difference between a 369-LO and a 369-HI model?
A: The difference lies entirely in the power supply card. The 369-LO runs on low voltage (20–60 VDC / 20–48 VAC), whereas the 369-HI operates on high voltage (50–300 VDC / 60–265 VAC).
Q: Does the “M” option on this unit require potential transformers (PTs)?
A: Yes. To calculate power factor, kW, and kVA, the metering board requires 3-phase AC voltage inputs wired from PTs to terminals B1 through B6 on the rear terminal block.
Q: Can I field-upgrade this 369-LO unit to add RTD inputs later?
A: You cannot insert an internal RTD board into a “0” RTD designated unit in the field. However, you can add GE’s external standalone Remote RTD (RRTD) module and wire it to one of the 369-LO’s rear RS485 serial ports.
Q: What warranty and test documents ship with this relay?
A: Every New Surplus and fully reconditioned 369-LO-0-M-0-0-0-E unit includes a comprehensive bench test report and a standard 1-year functional replacement warranty.
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