Product details

Origin:USA

Brand:bently

Product ID:991-25-50-02-01

product description 

991 Thrust Transmitter

Description

The 991 Thrust Transmitter is intended primarily for the original equipmentmanufacturers (OEMs) 

of centrifugal air compressors or small pumps, motors, orfans who prefer to provide a simple 4 to 20 

mA proportional axial displacement(thrust) signal as the input to their machinery control system. The 

transmitter is a2-wire, loop-powered device that accepts input from our 3300 NSv* proximityprobe and 

its matching extension cable (available in 5 m and 7 m system lengthoptions). The transmitter conditions 

the signal into appropriate engineering unitsproportional to the shaft’s axial position1, and provides it 

as a 4 to 20 mAindustry-standard signal for input to the control system where machineryprotection alarming 

and logic occurs2.

The 991 transmitter provides the following notable features:

l Integrated Proximitor* Sensor requires no external unit

l Non-isolated “PROX OUT " and "COM" terminals plus a coaxial connectorprovide a dynamic 

vibration and gap voltage signal output for diagnostics3.

l Non-interacting zero and span potentiometers under the Transmitter labelsupports loop adjustment.

l Test Input pin allows quick verification of loop signal output, using a variableDC voltage source as 

the input.

l A Power-up Inhibit circuit eliminates signal errors due to line voltagetransients.

l A Not OK/Signal Defeat circuit prevents high outputs or false alarms due to afaulty proximity probe 

or loose connection.

l Choice of DIN-rail clips or bulkhead mounting screws as standard optionssimplifies mounting.

l Potted construction for high humidity (up to 100% condensing)environments.

l Compatibility with 3300 NSv proximity probe allows transducer installationin small areas with minimal 

clearance, typical of centrifugal air compressors.