Vibration and Thrust Transmitters

Vibration and Thrust Transmitters

 Transmitters provide a 4-20 mA output along a twisted wire pair that measures shaft radial vibration, shaft position (thrust), or bearing/housing vibration. Two-wire transmitters are part of a current loop for various OEM control panels. Transmitters can be used for vibration or thrust position trending and can alarm on high vibration or thrust. Machinery diagnostics are not possible using the transducer’s 4-20 mA vibration or thrust position signal. Customers can perform limited machinery diagnostics by accessing the dynamic vibration waveform.

 

990 Vibration Transmitter
The 990 Vibration Transmitter provides a 4-20 mA signal proportional to relative vibration designed for use on smaller, non-critical machinery. Its primary use is on centrifugal air compressors with fluid-film bearings. While the 4-20 mA signal is used primarily for trending, the 990 transmitter also has separate “Prox Out” terminals and a “Prox Out” BNC jack which allows you to view the actual vibration waveform when used with the 990 test adapter.

991 Thrust Transmitter
The 991 Thrust Transmitter provides a 4-20 mA signal proportional to thrust position and is designed for use on smaller, non-critical machinery. Its primary use is on centrifugal air compressors with fluid-film thrust bearings. The 991 Thrust Transmitter can measure up to 1.2 mm or 50 mils of total thrust movement.
990 & 991 Transmitter Housings
These stainless steel housings were designed specifically for the 990 and 991 Transmitters and provide protection for these transmitters from adverse weather and other environmental conditions.

Seismic Transmitter
The Seismic Transmitter provides a 4-20 mA signal proportional to the 0-1 inch/sec 0-pk velocity movement of a roller element bearing housing or machinery housing. It is designed for use on non-critical machines. The transmitter automatically integrates the acceleration signal on the machine to vibration prior to sending the signal to the controller. The Seismic Transmitter also has a dynamic acceleration waveform output for advanced diagnostics that is accessible at the non-sensor end of the field wiring through either a patch panel or some other wiring technique. Ideally, you should use the 990 Test Adapter when capturing or viewing dynamic waveforms from the patch panel.

990 Test Adaptor

The 990 test adapter inverts and isolates the output signal from 990, 991 and Seismic Transmitters, allowing you to interface our Bently Nevada transmitters to AC-powered diagnostic equipment (such as ADRE®, oscilloscopes, and portable data collectors) while providing a high input impedance. The adapter inverts the phase of the “Prox Out” signal 180 degrees (to match standard vibration signals), isolates the test equipment output from the transmitter to prevent ground loop problems with the 4-20 mA current loop, and reduces the noise susceptibility of the transmitter dynamic output signal.

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