990-05-50-01-CN | Bently Nevada | 990 Vibration Transmitter

Description

The 990 Vibration Transmitter is a loop-powered, two-wire vibration measurement device designed for direct integration with machinery protection or condition monitoring systems in rotating equipment applications such as compressors, pumps, motors, and fans. It converts radial vibration sensed by a 3300 NSv proximity probe system into a proportional 4–20 mA signal representing peak-to-peak vibration amplitude, enabling continuous monitoring at the control system level.

This transmitter is typically applied where simplified vibration indication is required without full diagnostic vibration analysis capability. It incorporates an internal Proximitor-style signal conditioning stage, eliminating the need for an external driver module.

The 990-05-50-01-CN configuration defines a 0–5 mils peak-to-peak measurement range, a 5.0 meter system length, DIN rail mounting hardware, and region-specific approval marking for installation in regulated environments.

A secondary diagnostic output is available via PROX OUT interface, allowing access to raw vibration signal for troubleshooting using compatible test equipment with proper isolation.

Features

• Two-wire loop powered vibration transmitter (4–20 mA output)
• Compatible with 3300 NSv proximity probe system
• Internal signal conditioning (no external Proximitor required)
• Peak-to-peak vibration amplitude output
• PROX OUT diagnostic signal access available
• Non-interacting zero and span adjustment
• Power-up inhibit and NOT OK signal protection behavior
• DIN rail mounting hardware included
• Bulkhead mounting alternative available (variant dependent)
• Potted housing for high humidity environments

Applications

• Centrifugal air compressors
• Small centrifugal pumps
• Electric motors
• Industrial cooling fans
• OEM packaged rotating machinery
• Auxiliary machinery vibration trending
• Basic protection input to control systems

Technical Specifications

Connections / Interfaces

Installation Guidelines

Install the transmitter on a stable panel or DIN rail with minimal mechanical vibration influence. Maintain correct probe gap between 0.5 mm and 1.75 mm to ensure linear operation. Use shielded coaxial cable routing for probe signal integrity. Avoid running probe cables parallel to high-voltage power lines to reduce EMI coupling.

For PROX OUT diagnostic usage, apply proper signal isolation when connecting to grounded test instruments. Ensure enclosure sealing is maintained in high humidity environments.

FAQ

Is this transmitter suitable for vibration diagnostics?
It is designed for basic vibration monitoring and trending, not full diagnostic analysis.

Does it require an external signal conditioner?
No, the signal conditioning is integrated inside the transmitter.

What probe type is supported?
It is designed for use with the 3300 NSv proximity probe system.

Can PROX OUT be used directly on oscilloscope?
Yes, but isolation is recommended when using grounded test equipment.

What happens during probe failure?
The output enters NOT OK condition and drops below 3.6 mA to indicate fault.

Is this suitable for critical turbine monitoring?
No, it is intended for non-critical or auxiliary machinery applications.

Ordering Information

• Model: 990 - Vibration Transmitter
  
• Full-scale Option: -05 = 0–5 mils pp (0–100 µm pp)
  
• System Length Option: -50 = 5.0 meters (16.4 feet)
  
• Mounting Option: -01 = 35 mm DIN rail clips
  
• Agency Approval Option: -CN = regional compliance marking option