Description
The 25-01-05-01 configuration string defines a specific, fully optioned variant of the Bently Nevada 3500/25 Enhanced Keyphasor Module (specifically, part number 3500/25-01-05-01).
The 3500/25 is a half-height, two-channel module utilized to provide phase reference and tachometer signals to the monitoring and diagnostic modules within a 3500 Machinery Protection System rack. It processes input signals from proximity probes or magnetic pickups and converts them into digital once-per-turn timing pulses. These pulses enable precise calculation of shaft rotational speed and critical vector parameters like vibration phase angle, which is foundational for dynamic balancing and machinery diagnostics.
The specific options defined by the -01-05-01 suffix break down as follows:
- -01 (I/O Module Type): Enhanced Keyphasor I/O Module with Isolated Terminations
- -05 (Connector Type): Euro Style removable terminal blocks
- -01 (Agency Approval Option): CSA/NRTL/C (Class 1, Division 2, Groups A, B, C, and D)
Technical Specifications
| Parameter | Specification / Value |
| Brand | Bently Nevada (Baker Hughes) |
| Model Series | 3500 Series Machinery Protection |
| Full Part Configuration | 3500/25-01-05-01 |
| Input Channels | 2 channels (accepts single or multiple Keyphasor signals per rack) |
| Supported Sensors | Proximity probes, Magnetic pickups, Non-contact optical sensors |
| Input Signal Range | +0.8 V to −26.0 V (Non-isolated) / Up to ±30 V (Isolated inputs) |
| Speed Range Tracking | 1 to 99,999 RPM (Supported signal frequencies up to 20 kHz) |
| Output Pulse Accuracy | Phase measurement accuracy within ±1° up to 10 kHz |
| Rear Terminal Connections | Euro Style screw termination blocks |
| Hazardous Area Rating | Class 1, Division 2 / Zone 2 compliant via CSA |
| Backplane Current Draw | 600 mA at 5 V DC maximum |
Field Application and System Integration Notes
Isolated Terminations vs. Common Grounding
The -01 I/O option features structurally isolated input channels.
- Ground Loops: When running Keyphasor lines over extensive field distances to shared machine skids, minor differences in ground potential can introduce electrical noise. This noise manifests as ghost pulses or erratic speed readings.
- Mitigation: The isolated termination network on this variant breaks up common ground paths, preserving pulse shape and trigger consistency without the need for external galvanic signal isolators.
Hysteresis and Trigger Threshold Settings
Unlike standard proximity monitors that process smooth AC voltage curves, the Keyphasor functions via absolute edge detection.
- Configuring Thresholds: Through the 3500 Rack Configuration Software, you must manually define the auto-threshold or manual trigger setting based on the target notch depth on the shaft. For standard 8mm probes, a manual threshold of −10.0 V DC combined with a 2.0 V hysteresis window is standard practice to prevent double-triggering on shaft surface scratches or runout.
- Multiple Allocation: The pulses generated by this single module are distributed digitally across the internal 3500 backplane to all other dynamic modules (such as 3500/42M or 3500/50), allowing them to calculate synchronized phase correlations.
Physical Installation
Because the 3500/25 is a half-height module, it requires a dedicated half-height chassis slot framework or must occupy the upper or lower position of a standard slot when paired with another half-height card (like a 3500/15 power supply or another 3500/25).
Commercial and Procurement Data
- Product Condition: New Original (Factory Sealed) or Refurbished/Tested Surplus (with strict signal verification and pulse test records).
- Standard Warranty: 12-month comprehensive depot hardware warranty.
- Estimated Lead Time: Typically leaves warehouse stock within 1 to 2 business days.
- Pricing Notice: The market valuation for this product fluctuates based on hardware modification states and specific hazardous area tracking certifications. Contact our project logistics desk for a formal, time-stamped commercial quotation.
