BENTLY 86517-01-01-01-02 Vibration Monitoring Module for Aeroderivative Gas Turbine Protection

Brand Bently Nevada

Model BENTLY 86517-01-01-01-02

Product Overview

The BENTLY 86517-01-01-01-02 is a precision-engineered accelerometer interface module designed specifically for vibration monitoring applications in aeroderivative gas turbines and other high-speed rotating machinery. As a critical component within the Bently Nevada transducer system, the BENTLY 86517-01-01-01-02 functions as a charge amplifier that converts the high-impedance differential charge output from piezoelectric accelerometers into a low-impedance voltage signal suitable for long-distance transmission to monitoring instrumentation. This module is engineered to meet the demanding requirements of General Electric LM2500, LM5000, LM1600, and LM6000 series aeroderivative gas turbines, where accurate vibration measurement is essential for machinery protection and operational reliability.

The BENTLY 86517-01-01-01-02 accepts input from accelerometers with charge sensitivities of 50 pC/g or 100 pC/g, providing flexibility in sensor selection while maintaining precise signal fidelity. Its sophisticated signal processing chain includes a cascaded 6th order high-pass and 6th order low-pass Butterworth filter, delivering a 12th order bandpass response that effectively isolates rotor vibration components from structural noise and blade-passing frequencies. The module simultaneously produces two conditioned outputs: a buffered acceleration signal scaled to 10 mV/g peak and an integrated velocity signal at 100 mV/in/s peak, both designed for reliable transmission over extended cable runs to monitoring systems.

Positioned within the Bently Nevada 3300 and 3500 series monitoring frameworks, the BENTLY 86517-01-01-01-02 serves as the essential link between charge-coupled accelerometers mounted on turbine casings and the central monitoring and protection systems. Its DIN-rail mountable, hermetically sealed construction ensures reliable operation in harsh industrial environments, while agency approval options support deployment in hazardous area classifications where regulatory compliance is mandatory.

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Description

Technical Specifications

Parameter Name	Parameter Value
Product Model	BENTLY 86517-01-01-01-02
Manufacturer	Bently Nevada
Product Type	Accelerometer Interface Module
Transducer Charge Input Sensitivity	50 pC/g pk
Filter Corner Frequency	25 Hz high pass, 350 Hz low pass
Filter Response Type	12th order Butterworth (cascaded 6th order high-pass and low-pass)
DC Signal Bias Voltage	-10 Vdc nominal
Acceleration Output Sensitivity	10 mV/g pk balanced, 50 Ω nominal output impedance
Velocity Output Sensitivity	100 mV/in/s pk
Power Supply Voltage	-23 Vdc to -26 Vdc
Current Draw	22 mA maximum
Operating Temperature	0°C to +70°C (+32°F to +158°F)
Storage Temperature	-40°C to +85°C (-40°F to +185°F)
Dimensions (L×W×H)	139.7 mm × 82.6 mm × 76.2 mm
Weight	560 g (nominal)
Agency Approval	CENELEC (SIRA)
Mounting	DIN-rail compatible

Main Features and Advantages

The BENTLY 86517-01-01-01-02 distinguishes itself through a signal processing architecture specifically optimized for turbomachinery vibration monitoring. Its charge amplifier design accepts differential input from piezoelectric accelerometers, effectively rejecting common-mode noise that could otherwise corrupt vibration measurements in electrically noisy industrial environments. The module’s input stage accommodates total accelerometer and extension cable capacitance up to 8300 picofarads, enabling the use of standard low-noise extension cables without compromising signal integrity.

Dual output capability gives the BENTLY 86517-01-01-01-02 exceptional versatility. The buffered acceleration output provides raw dynamic data for high-frequency vibration analysis, while the integrated velocity output delivers the frequency range most relevant to machine condition monitoring and protection. Both outputs can be configured as single-ended or balanced two-wire differential connections, allowing seamless integration with a wide range of monitoring instruments and protection systems. The velocity signal is particularly valuable for detecting common machine malfunctions such as unbalance, misalignment, and bearing degradation, which manifest most prominently in the velocity domain.

The BENTLY 86517-01-01-01-02 incorporates factory-configured bandpass filtering that is tailored to the specific vibration characteristics of aeroderivative gas turbines. The standard 25 Hz high-pass and 350 Hz low-pass corner frequencies effectively pass the fundamental rotor vibration component while attenuating lower-frequency structural resonances and higher-frequency blade-passing excitations that are not indicative of rotor health. This filtering configuration, combined with the module’s high dynamic range of 750 g without barriers, ensures accurate capture of both normal operating vibration and transient events associated with developing faults.