Product Core Brief
- Part Number: 3500/25M-01-01-R0
- Brand: Bently Nevada (Baker Hughes)
- Series: Bently Nevada 3500 / 3500/25 Enhanced Keyphasor Module
- Core Function: Half-height, 2-channel Enhanced Keyphasor module that converts proximity probe or magnetic pickup signals into digital Keyphasor timing pulses for 3500 monitor modules.
- Product Type: 3500/25M Enhanced Keyphasor Module
- Key Specs: 2-channel half-height module | internal termination I/O | non-isolated Keyphasor I/O | CSA/NRTL/C approval (R0) | supports paired/TMR configurations | legacy/obsolete product
- Condition: New Original / New Surplus
Product Introduction
Bently Nevada 3500/25M-01-01-R0 is an Enhanced Keyphasor module for the Bently Nevada 3500 machinery protection system. The 3500/25M receives input signals from eddy-current proximity probes or magnetic pickups and converts them into digital Keyphasor signals that indicate when the Keyphasor mark on the rotating shaft coincides with the sensor.
The ordering code follows the 3500/25-AXX-BXX-CXX format: “01” in position A indicates a half-height 2-channel Keyphasor module; “01” in position B indicates a Keyphasor I/O module with internal terminations (non-isolated); “R0” in position C indicates CSA/NRTL/C approval. The module is typically supplied as front panel assembly 149369-01 with rear I/O module 125800-01 (Keyphasor I/O, internal terminations).
The 3500/25M is an improved version of the earlier 3500/25 Keyphasor module. It provides expanded Keyphasor signal processing capability while maintaining full downward compatibility in form, fit, and function with legacy Keyphasor modules (PWA 125792-01). Each module accepts up to two sensor inputs; the 3500 system can accept up to four Keyphasor signals in normal configuration and up to eight in paired configuration. It supports buffered Keyphasor outputs on the front panel via coaxial connectors and on the rear via European-style connectors.
The Keyphasor signal provides a precise once-per-revolution or multiple-events-per-revolution timing reference, enabling 3500 monitor modules and external diagnostic equipment to measure shaft rotative speed, 1X vibration amplitude, and phase angle. The module does not perform protection tripping; it supplies timing and phase reference signals to monitor modules such as 3500/40M, 3500/42M, and 3500/45.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer | Bently Nevada (Baker Hughes) |
| Part Number | 3500/25M-01-01-R0 |
| Product Type | Enhanced Keyphasor Module |
| Channels | 2 channels, half-height module |
| I/O Type | 01 — Internal termination, non-isolated Keyphasor I/O |
| Approval | R0 — CSA/NRTL/C |
| Typical Front Panel | 149369-01 Enhanced Keyphasor Module |
| Typical Rear I/O | 125800-01 Keyphasor I/O (Internal Terminations) |
| Input Signal | Proximity probe or magnetic pickup |
| Input Range (non-isolated I/O) | -0.8 V to -21.0 V (verify from label) |
| Sensor Supply | -24 Vdc, up to 40 mA per channel |
| Power Consumption | ~3.2 W typical |
| Outputs | 2 buffered Keyphasor outputs (front coaxial + rear European connector) |
| Status | Legacy / Obsolete |
Note: The 01-01-R0 configuration, 149369-01/125800-01 assembly pairing, and CSA/NRTL/C approval are documented for the 3500/25 Enhanced Keyphasor family. Exact firmware revision, input range for the installed I/O variant, and environmental ratings should be verified from the physical label and Bently Nevada 3500/25 documentation.
Quality Control Process (DYNAMIC GENERATION)
- Label and part number verification. We confirm the module reads 3500/25M-01-01-R0 and matches the Enhanced Keyphasor family.
- Configuration code check. We verify 01-01-R0 corresponds to 2-channel half-height module, internal termination non-isolated I/O, and CSA/NRTL/C approval.
- Front/rear panel assembly check. We confirm the front panel is 149369-01 and the rear I/O is 125800-01 (internal termination).
- Physical inspection. The front panel, coaxial Keyphasor outputs, connectors, LEDs, and mounting hardware are checked for damage or corrosion.
- Function family verification. We confirm it is not mislabeled as a monitor, relay, power supply, or communication gateway module.
- Final packaging. After inspection, the module is anti-static bagged and foam-packed for shipment.
Replacement Pitfall Guide (DYNAMIC GENERATION)
❗ Do not confuse it with a monitor or relay module. 3500/25M is a Keyphasor timing module; it cannot replace 3500/42M, 3500/45, 3500/32, or 3500/92.
❗ Verify the I/O type. The “01” I/O option is internal termination, non-isolated. Do not substitute with 02 (external termination), 03 (internal termination with barrier), or 04 (isolated internal termination) without confirming wiring compatibility.
❗ Confirm the approval suffix. “R0” indicates CSA/NRTL/C approval. If the installation does not require agency approval, a -00 variant may be acceptable; if ATEX/IECEx is required, a different approval code is needed.
❗ Check front/rear panel pairing. Ensure the module is supplied with 149369-01 front panel and the correct 125800-series rear I/O; mismatched I/O modules will cause wiring errors.
❗ Verify paired/TMR configuration. In TMR or paired arrangements, two Keyphasor modules operate in parallel. Confirm slot placement and primary/secondary signal assignment match the existing configuration.
❗ Confirm sensor compatibility. Non-isolated I/O expects proximity probe or magnetic pickup signals within the specified range; passive magnetic pickups require shaft speed above approximately 200 rpm (3.3 Hz).
❗ Handle as ESD-sensitive equipment. Use anti-static handling procedures during removal, installation, and storage.
Keep these in mind and you’ll cut 90% of rework time.
Compatibility Matrix & Benchmarks
| Original Model | Replacement / Successor Model | Compatibility Level | Migration Notes |
|---|---|---|---|
| Bently Nevada 3500/25M-01-01-R0 | Bently Nevada 3500/25M-01-01-R0 | Direct | Same part number; verify I/O and approval. |
| Bently Nevada 3500/25M-01-01-R0 | Bently Nevada 3500/25-01-01-01 | Direct | Same 01-01 configuration; 01 suffix is CSA/NRTL/C approval equivalent. Verify label. |
| Bently Nevada 3500/25M-01-01-R0 | Bently Nevada 3500/25-01-01-00 | Needs Adaptation | Same function; -00 has no agency approval. Acceptable if certification is not required. |
| Bently Nevada 3500/25M-01-01-R0 | Bently Nevada 3500/25-01-04-00/01 | Needs Adaptation | Isolated I/O variant; wiring and application differ. |
| Bently Nevada 3500/25 (legacy PWA 125792-01) | 3500/25M 149369-01 | Direct | Enhanced Keyphasor fully replaces legacy PWA 125792-01. |
| Bently Nevada 3500/25M | 3500/42M, 3500/45, 3500/32 | Not Compatible | Monitor, position, and relay modules; not functional substitutes. |
Benchmark highlights
- Bently Nevada 3500/25M Enhanced Keyphasor module.
- 01-01-R0 configuration: 2-channel half-height, internal termination non-isolated I/O, CSA/NRTL/C approval.
- Typically supplied as 149369-01 front panel with 125800-01 rear I/O module.
- Converts proximity probe or magnetic pickup signals into digital Keyphasor timing pulses.
- Provides buffered Keyphasor outputs via front coaxial and rear European connectors.
- Supports up to 4 Keyphasor signals per rack (normal) or 8 (paired configuration).
- Used for shaft speed, phase, and 1X vector measurement; does not perform protection tripping.
- Fully downward-compatible with legacy 3500/25 Keyphasor modules (PWA 125792-01).
- Legacy product; suitable for existing Bently Nevada 3500 system maintenance and like-for-like replacement.
