Product Overview

The Bently Nevada 991-06-70-01-00 is a compact, loop-powered thrust (axial displacement) vibration transmitter for continuous monitoring of rotating machinery. It accepts an eddy-current proximity signal from a compatible 3300 NSv probe system and converts the measurement into a standard 4–20 mA output for DCS/PLC integration.

This model integrates the signal conditioning function typically provided by a separate Proximitor unit, reducing panel space, wiring points, and installation complexity. Built for harsh industrial locations, the transmitter is commonly specified by OEMs and packagers for equipment where dependable thrust indication is required for protection and diagnostics.

Key Technical Characteristics

• Model number: 991-06-70-01-00

• Product type: Thrust Vibration Transmitter (loop-powered)

• Input: proximity probe signal from 3300 NSv probe systems (5 m / 7 m configurations typically supported)

• Output: 4–20 mA proportional to axial shaft displacement

• Diagnostic access: buffered dynamic output via PROX OUT terminal and coax connection for waveform/gap review

• Adjustments: independent zero and span trim for commissioning and calibration

• Startup behavior: power-up inhibit function to minimize false indications during energization

• Fault handling: NOT OK / signal defeat logic to reduce nuisance alarms caused by probe or wiring issues

• Mounting: DIN-rail mounting with option for bulkhead/panel installation

• Environmental protection: potted electronics suitable for high humidity and condensing conditions

Industrial Applications

• Thrust position monitoring on centrifugal compressors, pumps, and fans

• OEM skid packages requiring a direct 4–20 mA thrust signal to the control system

• Space-limited installations where separate signal conditioners are not desirable

• Machinery protection upgrades using existing proximity probe hardware and control system inputs

• Continuous axial displacement trending for reliability and maintenance planning