3500/25 PDF (User Manual)

Bently Nevada 3500/25 125792-01: Precision Speed and Keyphasor Monitoring Module

Product Description

The Bently Nevada 3500/25 125792-01 is a high-performance speed and Keyphasor monitoring module, a critical component of the Bently Nevada 3500 Machinery Protection and Condition Monitoring System. Specialized in measuring rotational speed and providing phase reference signals for rotating machinery, this module captures speed data and synchronizes vibration analysis with shaft position. It enables accurate detection of speed fluctuations, overspeed conditions, and rotational anomalies, while its Keyphasor output supports phase-synchronized vibration analysis—essential for diagnosing faults like unbalance and misalignment. With seamless integration into the 3500 system, it enhances machinery health monitoring by linking speed and vibration data, enabling proactive maintenance and preventing catastrophic failures.

Product Parameters

Parameter	Specification
Speed Input Channels	2 independent channels, compatible with magnetic pickup and optical sensors
Speed Measurement Range	0.1 RPM to 60,000 RPM
Keyphasor Output	1 channel, 0–5 VDC square wave (phase reference signal)
Accuracy	±0.01% of reading (at steady state)
Overspeed Detection	Configurable thresholds with adjustable delays (0.1–60 s)
Frequency Response	0.1 Hz to 10 kHz (speed signal processing)
Output Signals	4–20 mA analog output (speed proportional); digital data via 3500 backplane

Product Specifications

Series

The 3500/25 125792-01 is an integral part of the Bently Nevada 3500 series, a comprehensive suite of machinery protection and condition monitoring solutions. The 3500 series features modular components, including vibration monitors, temperature sensors, power supplies, and speed/Keyphasor modules, all engineered for seamless integration. Renowned for scalability, reliability, and compliance with industry standards, the series is trusted worldwide to protect critical rotating machinery in industries such as power generation, oil & gas, and chemical processing. The 3500/25 enhances the series by providing precise speed monitoring and phase reference capabilities, enabling accurate rotational fault diagnosis.

Features

Dual-Channel Speed Monitoring

2 independent channels support simultaneous speed measurement from two sensors, enabling redundant monitoring of a single machine or monitoring of two separate assets.

Wide Speed Range

0.1 RPM to 60,000 RPM measurement capability covers low-speed equipment (e.g., pumps) and high-speed machinery (e.g., gas turbines), ensuring versatility across applications.

Keyphasor Synchronization

Integrated Keyphasor output provides a phase reference signal, synchronizing vibration data with shaft position for accurate analysis of rotational faults like unbalance and misalignment.

Overspeed Protection

Configurable overspeed thresholds with adjustable delays trigger alarms or shutdowns, preventing damage from excessive rotational speeds in critical equipment.

High Accuracy and Stability

±0.01% accuracy at steady state ensures reliable speed measurement, critical for trend analysis and precise fault detection.

Function

The primary function of the 3500/25 125792-01 is to monitor rotational speed and provide phase reference signals for rotating machinery. It receives signals from magnetic pickups or optical sensors, processes them to calculate speed, and compares readings against user-defined thresholds for overspeed detection. Its Keyphasor output generates a square wave signal synchronized with shaft rotation, enabling vibration monitoring modules to correlate vibration data with specific shaft positions. This synchronization is critical for identifying rotational faults, as it links vibration patterns to mechanical events (e.g., shaft imbalance at specific angles).

Use

In industrial settings, the module is installed in the 3500 system rack, connected to speed sensors mounted near rotating shafts (e.g., turbine rotors, compressor shafts). It continuously measures speed, providing real-time data to operators via the 3500 system HMI or SCADA/DCS. The Keyphasor signal is routed to vibration modules for phase-synchronized analysis, aiding maintenance teams in diagnosing faults. During overspeed conditions, it triggers alarms or safety interlocks to protect equipment, ensuring safe operation of high-value assets.

Application Fields

Power Generation

Monitors speed in steam/gas turbines, generators, and feedwater pumps, detecting overspeed conditions and supporting vibration analysis to ensure reliable electricity production.

Oil and Gas

Protects centrifugal compressors, gas turbines, and pipeline pumps, withstanding high temperatures and corrosive environments to monitor speed and enable fault diagnosis.

Chemical Processing

Tracks speed in agitators, mixers, and reactor pumps, ensuring consistent process performance and detecting speed fluctuations that could indicate mechanical issues.

Pulp and Paper

Monitors roller speeds in paper machines and motor rotational speed, ensuring product quality by maintaining precise speed control and detecting misalignment.

Mining and Metals

Monitors crusher, conveyor, and mill drive speeds, withstanding dust and vibration to prevent equipment overload and optimize material processing efficiency.

In summary, the Bently Nevada 3500/25 125792-01 is a vital speed and Keyphasor monitoring module that enhances the 3500 system’s capability to protect rotating machinery. Its precision, wide speed range, and synchronization features make it essential for industries seeking accurate rotational monitoring and proactive fault detection.