Bently Nevada 990 Vibration Transmitter and 991 Displacement Transmitter The Bently Nevada 990 Vibration Transmitter and 991 Displacement Transmitter are used in conjunction with the 3300NSv eddy current probe for vibration monitoring in small compressor spaces. The Bently Nevada 990/991 Vibration and Displacement Transmitter is designed for centrifugal air compressors, small pumps, motors, or fans to transmit a simple shaft displacement signal, proportional to a 4 to 20 mA signal, to the unit's control system. The transmitter is a two-wire, loop-powered device that accepts input signals from our 3300XL eddy current sensor probe and its extension cable. The transmitter adjusts the signal to the appropriate peak vibration unit and scales this value into a 4 to 20 mA industry standard input signal to the control system for protection, alarm and logic control of the unit. Bentley 990 vibration transmitter has a full range of 100μm, 125μm, 200μm pp, etc., Bentley 991 displacement transmitter has a range of 0.6-0-0.6 mm, 1-0-1mm, etc., according to the needs of the site, can provide hazardous location area certification-CN.  The 991 transmitter has the following distinctive features: Integrated preamplifier unit, no external device required. Non-isolated “PROX OUT” and “COM” terminals plus coaxial connectors provide dynamic vibration and gap voltage signal outputs to enable troubleshooting. The zero and range potentiometers support loop adjustments without constraints on each other. A variable DC voltage source is used as the input, allowing quick verification of the loop signal output at the test input. Power-up suppression circuitry eliminates false irregularities due to line transient voltage signals/Signal Fault circuitry prevents high outputs or false alarms due to malfunctioning proximity probes or loose connections. Choice of DIN rail mounting or panel mounting screws as a standard option simplifies mounting sealing construction for high humidity environments Compatible with the 3300NSv eddy current sensor probe, the sensor can be mounted in tight areas with minimal clearance, typical of centrifugal air compressors. Bently Nevada 990 Vibration Transmitter Typical Models:[990-05-50-01-00](https://www.cwlyautomation.com/product/184.html "990-05-50-01-00"), [990-05-XX-01-00/CN](https://www.cwlyautomation.com/product/265.html "990-05-XX-01-00/CN"), etc. Bently Nevada 991 Displacement Transmitter Typical Models:[991-06-50-01-00](https://www.cwlyautomation.com/product/219.html "991-06-50-01-00"), 991-01-XX-01-00/CN, etc. Matching models: such as vibration displacement probe [330905-00-12-10-02-00](https://www.cwlyautomation.com/product/4231.html "330905-00-12-10-02-00"), 330103-00-08-10-02-00; probe extension cable 330930-040-00-00, 330130-040-00-00/CN, etc.