Description
Product Description
The Bently Nevada 3500/25 125800-01 Keyphasor® Input/Output Module is a dual-channel monitoring interface designed for rotational reference and phase measurement within the 3500 Machinery Protection System. This half-height module processes signals from proximity transducers and magnetic pickup sensors, converting them into stable digital timing pulses for precise shaft position tracking and synchronized vibration analysis.
Engineered for continuous-duty turbomachinery environments, the module supports both Standard and TMR (Triple Modular Redundant) rack architectures. Internal terminations simplify installation by reducing external wiring requirements while improving long-term connection reliability in high-vibration applications.
The module is commonly deployed in gas turbines, steam turbines, compressors, pumps, generators, and other rotating assets requiring accurate speed and phase reference signals for machinery diagnostics and protection systems.
Key Features
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Dual independent Keyphasor input channels
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Compatible with proximity probes and magnetic pickups
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Internal termination configuration for simplified cabinet wiring
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Supports Standard and TMR 3500 rack systems
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High-speed pulse processing for synchronous measurements
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Hot-replaceable module design
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Integrated diagnostics for signal validation and module condition monitoring
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Stable phase reference for vector analysis and orbit measurements
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Suitable for both low-speed and high-speed rotating equipment
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API 670 compliant machinery protection functionality
Technical Specifications
| Parameter |
Specification |
| Brand |
Bently Nevada |
| Series |
3500 Series |
| Model |
3500/25 |
| Part Number |
125800-01 |
| Product Type |
Keyphasor I/O Module |
| Termination Style |
Internal Terminations |
| Module Format |
Half-height module |
| Input Channels |
2 isolated channels |
| Supported Sensors |
Proximity probes, magnetic pickups, optional optical sensors |
| Input Voltage Range |
12 to 32 VDC |
| Maximum Input Current |
10 mA |
| Frequency Range |
0 to 10 kHz typical |
| Extended Frequency Capability |
Up to 20 kHz depending on sensor type |
| Output Type |
TTL-compatible pulse output |
| Buffered Output |
0–10 VDC |
| Output Current |
Maximum 20 mA |
| Phase Accuracy |
Typical ±0.5° |
| Rack Compatibility |
3500 Standard and TMR racks |
| Operating Temperature |
0°C to +65°C |
| Storage Temperature |
-40°C to +85°C |
| Relative Humidity |
5–95% non-condensing |
| Vibration Resistance |
5–2000 Hz, 2G |
| Shock Resistance |
30G, 11 ms |
| Protection Rating |
IP20 |
| Dimensions |
24.2 cm × 11.2 cm × 2.5 cm |
| Weight |
0.38 kg |
Applications
The Bently Nevada 3500/25 125800-01 module is used in machinery monitoring systems requiring accurate rotational timing references and phase synchronization, including:
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Steam and gas turbines
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Centrifugal compressors
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Industrial pumps
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Turbo generators
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High-speed motors
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Process plant rotating machinery
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Oil & gas production systems
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Power generation facilities
Operational Advantages
By generating accurate phase reference pulses, the module enables synchronized data collection across vibration monitoring channels. This improves machinery diagnostics such as:
Internal terminations also reduce installation complexity and improve cabinet maintainability in critical industrial environments.
FAQ
What is the primary function of the 3500/25 module?
The module provides rotational reference pulses used for speed measurement, phase calculations, and synchronized vibration monitoring within the Bently Nevada 3500 protection platform.
Does the module support redundant systems?
Yes. The module is compatible with both standard and Triple Modular Redundant (TMR) 3500 rack configurations.
Which sensors can be connected to this module?
The module accepts inputs from proximity probes, magnetic pickups, and in some applications optical sensors.
Can the module be replaced while the system is operating?
Yes. The module supports hot-swapping when used within compatible 3500 rack systems.
