Description

The BENTLY NEVADA 3500/20 125744-02 is a sophisticated Proximitor® Monitor module specifically engineered for the 3500 Machinery Protection System. This critical component serves as the primary interface for eddy current proximity transducer systems, providing continuous monitoring of radial vibration and axial position in rotating machinery. The 3500/20 125744-02 module is designed to accurately measure the distance between the probe tip and the observed surface, enabling precise detection of shaft vibration, eccentricity, and thrust position in turbines, compressors, pumps, and other high-value rotating equipment. Its advanced design incorporates specialized circuitry for probe powering, signal conditioning, and measurement validation, ensuring reliable operation in the most demanding industrial environments.

As part of Bently Nevada’s comprehensive machinery health monitoring solution, the 3500/20 125744-02 offers exceptional measurement accuracy and reliability. The module features dual-channel capability, allowing simultaneous monitoring of two independent measurement points from a single hardware component. Each channel provides complete signal processing including demodulation, filtering, and amplification of the raw probe signals, converting them into precise DC gap voltage and AC vibration signals. The module’s intelligent design includes comprehensive self-diagnostics that continuously monitor probe integrity, cable condition, and module health, ensuring maximum system availability and preventing false trips while maintaining critical machinery protection.

3500/20 125744-02 BENTLY

Technical Specifications

Parameter Name	Parameter Value
Product Model	3500/20 125744-02
Manufacturer	Bently Nevada (a Baker Hughes business)
Product Type	Proximitor® Monitor Module
Number of Channels	2 independent monitoring channels
Input Type	Eddy current proximity probes (8 mm, 11 mm, 14 mm, 25 mm, 35 mm)
Probe Power Supply	-18 VDC to -24 VDC @ 100 mA (typical)
Frequency Response	0 to 15 kHz (±3 dB) for vibration measurements
Dynamic Range	80 dB minimum
Gap Voltage Range	-2 VDC to -18 VDC
Scale Factor	200 mV/mil (7.87 V/mm) typical
Linearity	±1% of full scale
Output Signals	4-20 mA proportional to vibration or position, relay outputs
Operating Temperature	-30°C to +65°C (-22°F to +149°F)
Power Requirements	+5 VDC @ 800 mA, ±15 VDC @ 50 mA
Certifications	ATEX, IECEx, cFM, CSA, and other international standards

Main Features and Advantages

The BENTLY NEVADA 3500/20 125744-02 offers exceptional measurement precision through its advanced eddy current technology and signal processing capabilities. Each channel incorporates sophisticated demodulation circuitry that accurately extracts both the DC gap voltage (indicating average position) and AC vibration components from the raw probe signal. The module’s wide frequency response enables detection of both slow-roll conditions and high-frequency vibration events, providing comprehensive machinery protection across the entire operational spectrum. Automatic temperature compensation ensures measurement accuracy remains stable despite environmental temperature variations.

Advanced Diagnostic Capabilities: The module features comprehensive self-monitoring that continuously checks probe system integrity, including probe wiring, connector conditions, and probe functionality. Built-in diagnostics can detect open circuits, short circuits, and degradation in probe performance, providing early warning of potential measurement system problems. The module’s non-volatile memory retains all configuration settings, ensuring continuous operation even during power interruptions. Dual-level alarm setpoints with adjustable delay timers prevent nuisance trips while ensuring genuine dangerous conditions trigger appropriate protective actions.

Enhanced Integration and Flexibility: The 3500/20 125744-02 seamlessly integrates with the complete 3500 monitoring system, sharing data with other modules and providing comprehensive machinery protection. The module supports multiple output options including 4-20 mA analog outputs for each channel, relay outputs for alarm and danger setpoints, and digital communication via the 3500 rack interface. This flexibility allows the module to interface with DCS systems, PLCs, and other plant control systems, providing comprehensive vibration and position data throughout the facility.

Application Field

The BENTLY NEVADA 3500/20 125744-02 is deployed across multiple industries where precise measurement of shaft vibration and position is critical for operational safety and equipment reliability. In power generation facilities, the module protects steam and gas turbines, generators, and large pumping systems by monitoring radial vibration and thrust position. The oil and gas industry relies on the 3500/20 125744-02 for protecting critical compression equipment, pipeline pumps, and turboexpanders in upstream, midstream, and downstream operations, where it monitors shaft vibration and axial position to prevent catastrophic machinery failures.

In petrochemical and refining applications, the module provides essential protection for large centrifugal compressors, process pumps, and fan systems that operate continuously under demanding conditions. The module is particularly valuable in applications requiring precise measurement of shaft relative vibration, including gearboxes, large motors, and precision rotating equipment. The pulp and paper industry utilizes the 3500/20 125744-02 for monitoring large paper machine rolls and critical pumping systems. The module’s robust design and certifications make it suitable for hazardous areas and critical applications where equipment failure could result in significant safety, environmental, or economic consequences.

3500/20 125744-02 BENTLY

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