Bently Nevada 330878-91-00 Proximitor Sensor

Signal Conditioning for Precision Proximity Measurement

The Bently Nevada 330878-91-00 Proximitor sensor serves as the signal conditioning element for 3300 XL 5 mm and 8 mm proximity probe systems. This compact module converts the probe’s eddy-current signal into a proportional voltage output for monitoring systems. The unit measures 101.6 mm in height, 44.5 mm in width, and 120.7 mm in depth, with a weight of approximately 570 grams. It operates on a -24 Vdc negative supply and delivers a standard -7.87 V/mm sensitivity output. This sensor provides accurate displacement data for turbines, compressors, and other critical rotating machinery.

Input Characteristics and Output Performance

This Proximitor sensor provides a linear measurement range from 0.25 mm to 2.03 mm with a sensitivity of 7.87 mV/µm. It supports frequency responses from 0 to 10 kHz, capturing both static gap voltages and dynamic vibration components. The device accepts a target gap range of 0.38 mm to 2.03 mm from the probe tip to the shaft surface. Its output impedance measures 50 Ω, driving loads up to 10 mA without signal degradation. Such specifications ensure compatibility with a wide variety of monitoring and diagnostic systems.

Detailed Technical Specifications

Parameter	Specification
Height	101.6 mm
Width	44.5 mm
Depth	120.7 mm
Weight	Approx. 570 g
Supply Voltage	-24 Vdc (±5%)
Sensitivity	7.87 mV/µm
Linear Range	0.25 mm to 2.03 mm
Frequency Response	0 to 10 kHz
Output Impedance	50 Ω
Output Drive Capability	10 mA maximum
Target Gap Range	0.38 mm to 2.03 mm
Operating Temperature	-35°C to +85°C
Storage Temperature	-40°C to +100°C
Connection Type	Terminal block with BNC

Mounting and Interface Configuration

This Proximitor includes a DIN-rail mounting bracket for simplified installation in control cabinets or junction boxes. The terminal block accepts standard 22 AWG wires for power, probe input, and signal output connections. A front-panel BNC connector provides additional interface capability for diagnostic equipment and calibration tools. The unit stores negligible internal energy, supporting intrinsic safety ratings for hazardous zone installations. Users can pair this sensor with any 3300 XL 5 mm or 8 mm probe and the 3500 Monitoring System for complete vibration protection.

Installation Practices and Maintenance

Installing this Proximitor requires securing the DIN-rail bracket and connecting the probe and power cables per the terminal block layout. The front panel LED indicates proper power supply and probe gap status for quick diagnostics. Routine checks of the terminal screw torque will maintain reliable electrical connections over time. This sensor requires no periodic recalibration, though users should verify output using a calibrated target simulator annually. The robust construction and compact form factor suit retrofit applications and new installations alike.