Product Core Brief
- Model: URRHH
- Brand: GE (Multilin)
- Series: UR Universal Relay Modular Power Supply Platform
- Core Function: Regulate low-range 24–48 V DC auxiliary input to deliver stable internal rail power for UR protection relay CPUs and field I/O loops
- Product Type: Clip-in DIN rail mounted low-voltage DC power supply module
- Key Specs: 35 W max continuous output | 24–48 V DC low-range input | Built-in 4 A overcurrent fuse ⚠️ EOL — limited stock remaining
Product Introduction
GE URRHH draws station DC auxiliary power and converts it to filtered internal rail voltage to power Multilin UR relay CPUs, analog transducers, and binary contact inputs. It runs internal self-tests to flag degraded output voltage via front panel LED indicators. This unit differs from URSHA by only supporting DC low-range input and cutting total power capacity from 125 W to 35 W. It maintains ±1 % steady-state output voltage tolerance across -20 °C to +60 °C cabinet operating bands and supports parallel redundant feeding for no-break substation protection.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Supported input voltage range | 24 V DC to 48 V DC SELV low-range DC only |
| Maximum continuous power output | 35 W peak full load at 55 °C ambient |
| Steady-state output voltage regulation | ±1 % full scale across rated temp range |
| Internal overcurrent protection | 4 A / 250 V fast-blow fuse integrated |
| Redundancy capability | Dual URRHH modules parallel feed, automatic load sharing |
| Minimum cabinet airflow | 150 LFM to prevent thermal derating |
| Operating cabinet temperature | -20 °C to +60 °C |
| Storage temperature range | -40 °C to +85 °C |
| Mechanical mounting | EN 50022 standard 35 mm DIN rail clip-in design |
| Unit housing construction | Perforated vented steel for passive heat dissipation |
| Net unit weight | 1.3 kg |
| Compliance standards | IEC 61000-6-2 industrial EMC, UL 61010, CE certified |
Quality Control Process (Engineer’s Perspective)
- Incoming Verification: Cross-reference serial numbers against GE Multilin UR spare asset database to flag counterfeit hardware. Inspect green spring terminal blocks, metal vent housing, and front power status LED with a 10x magnifier for pin oxidation or cracked casing; log serial numbers for substation traceability.
- Live Functional Test: Mount the unit on a grounded DIN rail test bench paired with a UR9HH relay CPU and variable resistive load banks. Inject full 35 W load, run continuous 26-hour testing while logging cabinet temperature shifts and recording output voltage deviation.
- Electrical Parameter Test: Use a 500 V Megger to measure insulation resistance between DC input terminals and chassis ground; pass threshold set at >10 MΩ. Verify PE protective ground loop resistance below 0.5 Ω with a Fluke 115 multimeter.
- Firmware Verification: This power supply uses analog switching circuits with no programmable onboard firmware. Photograph internal redundancy jumper positions printed on the unit PCB for field commissioning reference.
- Final QC & Packaging: Wipe perforated metal housing with anti-static microfiber cloth, cap all signal terminal blocks with plastic dust covers. Seal inside a shielding ESD bag, attach a QC Passed label stamped with full test completion date.
Replacement Pitfall Guide
❗ Firmware Mismatch: The unit has no onboard firmware, but host UR9HH relay CPU firmware v7.0 and older lack low-range DC power fault supervision logic. Match exact CPU firmware builds before rack power-up, or under-voltage alarms will not trigger during supply degradation. ❗ DIP Switch / Jumper Misconfiguration: Factory default redundancy parallel jumper is disabled. Most critical substation protection racks require the jumper enabled for dual-feed power setups; missed settings create single-point power failure risk for relay trip logic. ❗ Terminal / Cable Incompatibility: This unit uses 2.5 mm spring DC input terminals, unlike high-range URSHA 4 mm AC power blocks. Undersized wire strands loosen under cabinet fan vibration and trigger intermittent low-voltage lockout; shield drain wires must land on dedicated protective ground bars only. ❗ Power Supply Mismatch: Full 35 W peak load requires 20 % rack power budget overhead. Undersized station DC battery banks trigger input under-voltage lockout and blank relay HMI displays during peak generator startup. ❗ ESD Damage: Dry cabinet environments above 40 % relative static risk degrade internal switching MOSFET chips on the unit. Always use an anti-static mat and grounded wrist strap when handling exposed terminal pins and vented PCB internal layers. Keep these in mind and you’ll cut 90% of rework time.
Compatibility Matrix & Benchmarks
Compatibility Matrix
- URSHA → URRHH : Needs Adaptation — URSHA supports 120–240 V AC input, power capacity reduced from 125 W to 35 W
- UR9HH Protection Relay CPU → URRHH : Direct — identical DIN rail footprint, no panel cutout modification required
- V7768-312000 VME SBC → URRHH : Incompatible — separate VME64 backplane architecture, no shared power bus mapping
