Product Core Brief
- Model: 3500/25-01-03-02
- Brand: Bently Nevada (Baker Hughes)
- Series: 3500 Machinery Protection System
- Core Function: Enhanced Keyphasor Module that converts proximity probe or magnetic pickup signals into digital Keyphasor pulses for phase, speed, and vector measurement.
- Product Type: 3500 Enhanced Keyphasor Module
- Key Specs: Half-height, 2-channel | 149369-01 main module + 135473-01 isolated I/O module with internal terminations | buffered Keyphasor outputs | CSA/NRTL/C approved | replaces legacy 125792-01
- Condition: New Surplus / Factory New (confirm firmware, I/O module pairing, and rack configuration before procurement)
Product Introduction
The Bently Nevada 3500/25-01-03-02 is an Enhanced Keyphasor Module assembly for the 3500 Machinery Protection System. It consists of the 149369-01 Enhanced Keyphasor main module and the 135473-01 isolated I/O module with internal terminations.
The module receives signals from eddy-current proximity probes or magnetic pickups and converts them into digital Keyphasor pulses. Each pulse indicates when a physical mark on the rotating shaft passes the sensor. These pulses provide precise timing references that allow 3500 monitor modules and external diagnostic equipment to measure shaft rotative speed, 1X vibration amplitude, phase angle, and other vector parameters.
This is an improved 3500 system module. It offers expanded Keyphasor signal processing compared with the earlier design, while maintaining full downward compatibility in form, fit, and function with legacy Keyphasor modules. The 149369-01 main module completely replaces the older PWA 125792-01.
The 3500/25-01-03-02 is typically used in steam turbines, gas turbines, compressors, generators, fans, pumps, and gearboxes where phase-synchronized vibration monitoring is required.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Product Type | 3500 Enhanced Keyphasor Module |
| Brand | Bently Nevada (Baker Hughes) |
| Model | 3500/25-01-03-02 |
| Main Module | 149369-01 Enhanced Keyphasor Module |
| I/O Module | 135473-01 Isolated I/O Module, Internal Terminations |
| Channel Count | 2 channels (half-height module) |
| Input Signal | Proximity probe or magnetic pickup |
| Isolated Input Range | +5 V to -11 V typical for isolated I/O module |
| Non-Isolated Input Range | -0.8 V to -21.0 V typical for non-isolated I/O module |
| Buffered Outputs | 2 buffered Keyphasor outputs (front-panel BNC and rear Euro connector) |
| Approvals | CSA/NRTL/C (code 02) |
| Power Consumption | Approximately 3.2 W typical |
| Compatible Monitors | 3500/40M, 3500/42M, 3500/45, 3500/40, 3500/42 |
Exact input range, buffered output availability, and installation rules must be confirmed against the installed 3500 rack configuration and OEM documentation.
Quality Control Process (DYNAMIC GENERATION)
- Part-number verification: Confirm 3500/25-01-03-02, 149369-01, and 135473-01 on module labels.
- Visual inspection: Check front-panel connectors, rear I/O module, mounting clips, and label for physical damage or corrosion.
- Module pairing check: Confirm the 149369-01 main module is correctly mated with the 135473-01 isolated I/O module.
- Connector integrity check: Inspect BNC Keyphasor outputs, rear Euro connector, and internal ribbon connections for bent pins or poor contact.
- Electrical verification: Check supply voltage, OK/TX-RX LED status, and buffered output pulse under safe test conditions.
- Configuration verification: Confirm channel count, isolation type, and CSA/NRTL/C approval code match the installed 3500 rack.
Replacement Pitfall Guide (DYNAMIC GENERATION)
❗ Do not confuse 135473-01 with a display or vibration monitor module. Some third-party listings incorrectly describe 135473-01 as a 3500 display unit or vibration monitoring module. In the 3500/25-01-03-02 assembly, 135473-01 is the isolated I/O module for the Enhanced Keyphasor Module, not a standalone display or 4-channel monitor.
❗ Match the full order code. The suffix 01-03-02 defines channel count, I/O module type, and approvals. Substituting 01-01-00, 01-02-01, or 02-03-01 may change channel count, isolation, terminal type, or certification status.
❗ Verify isolated vs. non-isolated I/O. Code 03 indicates an isolated I/O module with internal terminations. Isolated and non-isolated versions have different input ranges and grounding behavior.
❗ Confirm rack slot compatibility. The 3500/25 main module is a half-height module and requires the correct mounting adapter when installed in a full-height slot. A 3500 rack supports a limited number of Keyphasor modules depending on configuration.
❗ Do not hot-swap without procedure. Although 3500 modules support hot insertion under defined conditions, Keyphasor modules supply sensor power and provide timing references to other monitors. Replacement should follow OEM and site safety procedures.
❗ Treat as a timing-critical module. Incorrect Keyphasor configuration can affect phase measurement, vector diagnostics, speed indication, and protection logic across the entire 3500 rack.
Compatibility Matrix & Benchmarks
| Original Model | Replacement / Successor Model | Compatibility Level | Migration Notes |
|---|---|---|---|
| Bently Nevada 3500/25-01-03-02 | Same 3500/25-01-03-02 assembly | Direct | Match main module, I/O module, and approval code. |
| Bently Nevada 3500/25-01-03-02 | 3500/25 with 149369-01 + other I/O modules | Needs Verification | Confirm isolation, terminal type, and approval code. |
| Bently Nevada 3500/25-01-03-02 | Legacy 3500/25 with PWA 125792-01 | Upgrade | 149369-01 replaces 125792-01; verify I/O module pairing. |
| Bently Nevada 3500/25-01-03-02 | 3500/22M, 3500/40M, 3500/42M | Not interchangeable | Different module functions; Keyphasor cannot replace monitor or RIM modules. |
Benchmarks:
- 3500 Enhanced Keyphasor Module assembly for the Bently Nevada 3500 Machinery Protection System.
- Consists of 149369-01 Enhanced Keyphasor main module and 135473-01 isolated I/O module with internal terminations.
- Provides 2-channel digital Keyphasor pulses for phase, speed, and vector measurement.
- Isolated I/O module with CSA/NRTL/C approval; compatible with proximity probes and magnetic pickups.
- Third-party listings that describe 135473-01 as a display unit or vibration monitor are incorrect; in this configuration it serves as the isolated I/O module for the 3500/25 Keyphasor Module.
