Product Core Brief

• Model: 149992-01
• Brand: Bently Nevada (Baker Hughes)
• Series: 3500 Machinery Protection System
• Core Function: 16-channel relay output module providing programmable voting logic and hardware trip/alert outputs for comprehensive machinery protection.
• Product Type: 16-Channel Relay I/O Module
• Key Specs: 16 Independent Relays | Programmable Logic | API 670 Compliant
• Condition: New Surplus / OEM Original

Key Technical Specifications

• Module Type: 3500/33 16-Channel Relay Monitor
• Relay Capacity: 16 Independently Programmable Relays
• Voting Logic: Supports 1oo2, 2oo2, 2oo3, and custom “AND”/”OR” logic configurations
• Contact Rating: Typically 5A @ 250 VAC / 30 VDC (Verify specific datasheet)
• Response Time: < 10 ms (Hardware trip path)
• System Compatibility: 3500 M-Series Monitors (3500/40M, 3500/42M, 3500/45M, etc.)
• Configuration: Requires 3500 Rack Configuration Software
• Protection Standard: API 670 / SIL 2 Capable (in redundant configurations)
• Front Panel Indicators: Relay Status LEDs, Bypass Switch
• Physical Dimensions: ~2.5 cm × 27.9 cm × 25.4 cm
• Weight: ~0.7 kg

 

Product Introduction

Serving as the high-density output backbone for the 3500 ecosystem, this Bently Nevada 149992-01 provides sixteen independently programmable relay outputs in a single module. It executes complex voting logic directly from the backplane, consolidating what would previously require four 4-channel relay modules into one space-efficient unit.

Unlike older 3300 series systems, this module integrates seamlessly with 3500 software configuration, eliminating front-panel DIP switches. Each relay can be programmed with custom “AND”/”OR” logic using any combination of monitor channels, allowing for sophisticated protection schemes like cross-channel vibration/temperature correlation or multi-sensor overspeed voting.

 

QA & Testing SOP

Relay modules are the final hardware protection layer. We verify both the logic path and physical contact integrity.

1. Anti-Counterfeit & Visual Audit: We inspect the Bently Nevada silkscreen, verify the 149992-01 part number, and check all 16 relay sockets and front panel bypass switch for physical damage or oxidation.
2. Backplane Communication Test: We install the module in an OEM 3500 test rack to verify it enumerates correctly and accepts configuration parameters from the 3500 Configuration Software.
3. Relay Actuation Test: We force each of the 16 relays through the software and verify the status LEDs illuminate and the contacts change state, confirming all driver circuits are functional.
4. Contact Resistance Check: Using a low-resistance ohmmeter, we verify the closed-contact resistance is within spec (< 100 mΩ), ensuring the relay won’t fail to pass trip current during an emergency.
5. ESD Safe Packaging: Relay driver ICs are sensitive to electrostatic discharge. We pack these modules in anti-static shielding bags with desiccant to prevent latent semiconductor damage.

Installation Pitfalls & Guide

❗ Wiring the Trip Circuit: Never wire critical protection relays as simple “make” contacts. Use a de-energize-to-trip philosophy: wire the relay normally closed (NC) so that a loss of power, broken wire, or failed module results in a safe trip state, not a masked hazard.

❗ Voting Logic Configuration: The 3500/33 supports complex voting (e.g., 2oo3 for high availability). Misconfiguring this logic during commissioning can result in nuisance trips or, worse, failure to trip. Always simulate all voting scenarios in the configuration software before connecting field wiring.

❗ Relay Contact Rating: Do not exceed the 5A contact rating. If you’re driving a large motor starter coil or multiple DCS inputs, use an interposing relay. Exceeding the rating will weld the contacts closed, rendering the protection useless.

❗ Slot Position: This module can be placed in any available slot to the right of the frame interface module (RIM), but always verify your configuration file matches the physical slot assignment before powering up.

Replacement SOP:

1. Pre-Install: Document the current relay assignments and voting logic; place the machine in bypass/maintenance mode before swapping.
2. Removal: Power down the 3500 rack; disconnect field wiring (label everything!); remove mounting screws and extract the module.
3. Install: Slide the 149992-01 into the designated slot, ensure firm backplane seating, and secure mounting screws.
4. Power-On Test: Power up the rack, download the configuration, and perform a full relay actuation test with the machine still in bypass before returning to service.

 

Technical FAQ

What is the difference between 149986-01 and 149992-01?
149986-01 is the standard 16-channel relay output module. 149992-01 is the failsafe variant with enhanced self-diagnostics and SIL 3 capability. For most API 670 applications, 149986-01 is sufficient, but if your safety case requires SIL 3, verify whether you need the failsafe version.

Can I use this module for SIL 2 protection?
Yes, but only when configured in a redundant architecture (e.g., dual 3500/33 modules with 2oo2 voting or paired with a 3500/34 TMR module). A single 149992-01 module alone does not meet SIL 2 requirements for critical protection applications. Always consult the Bently Nevada SIL Certificate for your specific configuration.

Do I need to reconfigure this module after installation?
Yes. The 3500/33 does not store its configuration on the module itself; it pulls configuration from the 3500/22 TDI or the rack configuration software at power-up. You must have a valid configuration file loaded in the system before the relays will function.

Can I hot-swap this relay module?
While the 3500 system supports online maintenance, hot-swapping a 16-channel relay module can cause momentary contact chatter or state changes across multiple protection circuits. For critical protection relays, we recommend scheduling a brief maintenance window to safely bypass and power down the slot before replacement.

Why is this sold as new surplus?
This unit was pulled from sealed OEM overstock or an unfulfilled project before installation. We test it on our OEM 3500 test racks to verify functionality, but we aren’t replacing relays or reflowing the PCB. You’re getting unused factory components with original manufacturing tolerances at a fraction of the active OEM list price.