Bently Nevada 18745-03 3300 Series Proximitor Power Supply Board

Description

Product Introduction

The Bently Nevada 18745-03 is an internal power supply sub-module card engineered for the legacy 3300 Series Machinery Protection System. Operating inside dual-channel vibration and thrust position monitor assemblies (such as the 3300/16 Dual Radial Vibration Monitor or 3300/20 Dual Thrust Position Monitor), this card converts raw rack backplane power into a regulated, low-noise -24V DC supply dedicated to powering field-mounted proximity transducer systems.

By isolating the power supplied to external Proximitor sensors from the main digital/analog logic circuits, the 18745-03 prevents field noise, ground loops, and cable induction from degrading vibration signal accuracy. Its rugged component architecture ensures precise voltage stability across industrial temperature ranges, preserving continuous machinery protection across critical rotating assets.

Key Technical Specifications

Application Scenarios & The “Trench” Experience

A large boiler feed pump on a power plant skid triggers a “NOT OK” channel status light on its 3300/16 Dual Vibration Monitor. The DCS shows an immediate loss of radial vibration data on the drive-end bearing. Field technicians verify that the 3300 XL Proximitor sensor and field wiring are completely intact, but the -24V DC transducer power rail at the rack’s rear terminal strip has dropped to zero volts. Swapping the faulty internal 18745-03 power supply board inside the monitor card restores stable -24V DC to the field sensor, clearing the channel fault and bringing critical vibration protection back online in under 15 minutes without replacing the entire monitor assembly.

• Power Generation Turbines: Delivers stable power to proximity probes monitoring shaft vibration and axial thrust position.
• Refinery Centrifugal Compressors: Powers dual-channel radial vibration sensors on high-speed process gas machinery.
• Large Industrial Pumps & Motors: Ensures continuous -24V DC power feed to eddy-current transducer systems for predictive maintenance.
• 3300 Rack Maintenance & Spares: Essential internal replacement card for extending the service life of legacy Bently Nevada 3300 racks.

18745-03

18745-03

Transparency SOP: Quality Assurance & Testing

1. Visual & Structural Inspection: PCB traces, edge connector contacts, solder joints, and onboard components are inspected for thermal discoloration, micro-cracks, or component degradation.
2. Backplane & Power Regulation Test: The 18745-03 board is installed in an active Bently Nevada 3300 test chassis to verify backplane bus power engagement and voltage transformation.
3. Load Calibration & Ripple Audit:
   • Voltage Output Check: Tested under full dual-channel Proximitor load (0 to 100 mA) to confirm output holds strictly at -24V DC ±0.5V.
   • Noise & Ripple Check: Scope verification ensures AC noise and ripple are minimal, preventing false vibration readings or signal jitter.
4. Thermal Burn-In Test: Operated under continuous full load for 2 hours to confirm thermal stability of voltage regulators.
5. Final ESD Packaging: Cleaned, treated with protective film on edge connectors, wrapped in static-shielding bags, and sealed in heavy-duty foam packaging.

The Veteran’s Tech Trap Guide (Crucial Value-Add)

• ⚠️ Internal Sub-Module vs. Main Rack Power Supply: The 18745-03 is an internal power supply card that resides inside individual 3300 monitor modules. It is not the main 3300 system power supply (e.g., 3300/12 or 3300/14). Do not connect line voltage directly to this board.
• ❗ Field Wiring Short Circuit Checks: Before installing a fresh 18745-03 card, check the field wiring between the rack rear terminal block and the field Proximitor. A pinched field cable or dead short between -24V and COM will immediately trip or damage the short-circuit protection on the new board.
• ⚠️ Verify Correct Part Revision: Bently Nevada produced several variations of internal power boards for the 3300 series. Ensure your existing board matches the 18745-03 revision designation to guarantee backplane trace and pinout compatibility.
• ❗ Channel “NOT OK” LED Diagnostics: If a channel “NOT OK” light remains illuminated after board replacement, check the DC gap voltage at the probe. A gap voltage outside the -2 to -18 VDC operating window indicates a damaged probe or incorrect physical probe standoff distance, not a power supply fault.

Frequently Asked Questions (FAQ)

Q: What is the primary function of the Bently Nevada 18745-03?

A: It is an internal power supply board used inside 3300 series monitor modules to convert backplane power into a regulated, isolated -24V DC supply for field proximity sensors.

Q: Can I use the 18745-03 board in the newer 3500 Series system?

A: No. The 18745-03 is designed specifically for the legacy 3300 Series backplane architecture and cannot be used in 3500 racks.

Q: Is the 18745-03 still manufactured by Bently Nevada?

A: No. The 3300 series has been retired by Bently Nevada. This card is available as New Surplus or fully reconditioned/tested stock to keep existing 3300 racks operational without costly system migrations.

Q: What happens if the 18745-03 board fails?

A: The affected monitor channels will lose -24V DC field power, triggering a “NOT OK” status alarm on the monitor faceplate and disabling vibration monitoring on those channels.

Q: What warranty is provided on surplus or reconditioned 18745-03 cards?

A: All New Surplus and reconditioned Bently Nevada 18745-03 boards include a full 12-month replacement warranty from the invoice date.