Description
Key Technical Specifications
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Model Number: 3500/15-01 125840-02
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Manufacturer: Bently Nevada (Baker Hughes)
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Input Voltage: 120V AC (±10%, 50/60Hz, single-phase)
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Output Voltage: 24V DC (±5% regulation, 100W continuous)
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Efficiency: 85% typical (at 120V AC input)
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Cooling: Convection (fanless, relies on rack airflow)
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Operating Temperature: 0°C to +65°C (rack-mounted, derates above +50°C)
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Storage Temperature: -40°C to +85°C
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Electrical Isolation: 3000Vrms (input-to-output, per IEC 60664-1)
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Power Factor Correction: Active (≥0.95 at full load)
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Dimensions: 119mm x 25mm x 102mm (WxHxD, 3500 half-height slot)
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Weight: 0.18kg
Bently 3500/15-01 125840-02
Field Application & Problem Solved
In the field, small-to-medium 3500 Monitoring System racks (e.g., auxiliary pump skids, small turbine lube oil systems) often get underserved by bulky dual-input power supplies. These racks don’t need 240V auto-ranging—they need a compact, reliable 120V AC solution that won’t fail in noisy plant environments. This module solves that with a single-input 120V design, 100W output (enough for 4-5 3500 modules), and convection cooling (no fan to clog with dust in paper mills). You’ll find it in wastewater treatment plants powering pump monitor racks, food processing facilities running mixer protection systems, or small gas turbines with minimal I/O. Its core value is simplicity and stability: the 125840-02 firmware adds tighter voltage regulation (±2% vs. ±5% base), preventing nuisance trips from minor grid sags. For example, in a brewery’s bottling line, it survived 6 months of 110V “brownouts” without dropping power to the 3500/42M vibration monitor—something the old 240V module couldn’t handle.
Installation & Maintenance Pitfalls (Expert Tips)
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Single Input Voltage Confirmation: Rookies assume “120V” means any North American outlet. Verify with a multimeter—some plants have 100V legacy circuits. The 3500/15-01 isn’t auto-ranging; 240V will fry the input stage. Label the terminal block clearly.
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Convection Cooling Clearance: No fan means it relies on rack airflow. In a crowded cabinet, blocked vents cause thermal shutdown (above +65°C). Leave 2-inch clearance above/below, and clean dust quarterly—especially in flour mills or sawmills.
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Loose Terminal Screws: Vibration from nearby motors loosens input/output screws, causing intermittent power drops. Torque to 8 in-lbs (0.9 Nm) and use lock washers. I’ve fixed 2 “random” trips this year by tightening these.
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Firmware for Voltage Sag Recovery: The 125840-02 firmware fixes a rare “brownout lockout” bug (v4.5 and earlier). If your plant has frequent sags, update via Bently Update Manager—unpatched modules may not restart automatically.
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Avoid Overloading Output: 100W total capacity. A 3500/42M (0.16kg, 2W) + 3500/25 (0.15kg, 1.5W) + 3500/92 (0.13kg, 1W) = ~4.5W. Don’t add extra modules without calculating load—exceeding 100W trips the overcurrent protection.
Bently 3500/15-01 125840-02
Technical Deep Dive & Overview
The 3500/15-01 125840-02 is a half-height power supply module for Bently’s 3500 Machinery Protection System, tailored for small racks with single-phase 120V AC input. It uses a switched-mode power supply (SMPS) with active PFC to convert 120V AC to stable 24V DC, delivering 100W via the 3500 rack backplane. The convection cooling design eliminates fans—critical for dusty or humid environments (e.g., offshore platforms). The 125840-02 firmware enhances voltage regulation (tightens output to ±2%) and adds faster brownout recovery (survives 85V dips for 20ms). It mounts in any 3500 half-height slot, drawing power from a dedicated 120V circuit and feeding the backplane. Unlike dual-input models, it’s lean and purpose-built for smaller systems, pairing with the 3500/05 rack interface to power essential monitors (vibration, keyphasor, communication). In short, it’s the “workhorse” for compact 3500 racks—small enough to fit, tough enough to last.
