Product Overview

The 990-05-70-01-05 is a high-performance 2-wire vibration transmitter designed to provide continuous machinery protection through a standard 4–20 mA loop signal. This Bently Nevada 990 series module acts as an integrated signal conditioner, combining the functions of a Proximitor sensor and a transmitter into a single, compact housing. It is specifically engineered to interface with 3300 NSv proximity probes and extension cables, converting eddy current measurements into a linear current output proportional to peak-to-peak vibration. This architecture is particularly favored by OEMs for centrifugal air compressors, high-speed motors, and industrial fans where space-saving integration into a DCS or PLC is required.

Hardware Parameters and Technical Characteristics

This transmitter is built to maintain signal integrity in electrically noisy and hazardous environments. Key hardware features include:

• Model Number 990-05-70-01-05

• Input Compatibility 3300 NSv Proximity Transducer System

• System Length 5.0 Meters (Option -05)

• Full-Scale Range 0 to 100 µm (4.0 mils) peak-to-peak (Option -70)

• Mounting Interface Bulkhead Mounting (Option -01)

• Signal Output 4 to 20 mA DC (Loop-powered)

• Diagnostic Interface Coaxial BNC connector and non-isolated "PROX OUT" terminals for buffered gap and dynamic signal analysis

• Calibration Accessible non-interacting zero and span potentiometers for precise field tuning

• Fault Protection Integrated "Not OK" and Signal Defeat logic to mitigate false alarms from sensor failure

• Hazardous Area Certification CSA Division 2, ATEX Zone 0/2, and ABS Maritime approvals (Option -05)

Industrial Applications and Operational Benefits

The 990-05-70-01-05 is a primary component in Turbine Supervisory Instrumentation (TSI) for medium-to-large rotating machinery. Because it utilizes the 3300 NSv (Narrow Side-view) probe system, it is exceptionally effective in tight installation clearances where standard 8mm probes might experience side-view interference.

Common applications include monitoring radial vibration on fluid-film bearing machines, providing early detection of rotor unbalance, shaft misalignment, or bearing degradation. The loop-powered 4–20 mA interface allows for long-distance signal transmission directly to control room systems without the need for a separate monitoring rack. Furthermore, the buffered diagnostic output enables technicians to connect portable data collectors or oscilloscopes for advanced frequency spectrum analysis without interrupting the primary protection loop.