Bently Nevada 3300/20-12-01 Thrust Position Monitor

Dual-Channel Axial Displacement Measurement Module

The Bently Nevada 3300/20-12-01 thrust position monitor continuously tracks axial shaft displacement in rotating machinery. This module processes input signals from two 3300 XL 8 mm Proximitor sensors. It provides essential protection against thrust bearing wear and rotor axial movement. The monitor serves steam turbines, compressors, and large motor-driven equipment.

Technical Specifications

Parameter	Specification
Model Number	3300/20-12-01
Brand	Bently Nevada
Category	Thrust Position Monitor
Channels	2 independent
Input Type	3300 XL 8 mm Proximitor, 200 mV/mil
Scale Factor	7.87 V/mm
Standard Range	-0.100 to -0.016 inch (-2.54 to -0.406 mm)
Zero Position	-0.050 inch (-1.27 mm)
Input Impedance	50 kΩ minimum
Display	Non-multiplexing vertical LCD
Recorder Outputs	4-20 mA, 0 to -10 VDC, or +1 to +5 VDC
Frequency Response	DC to 10 Hz
Accuracy	±0.33% of full-scale
Power Requirement	+24 VDC nominal
Power Consumption	2.0 W maximum
Weight	1.02 kg
Dimensions (HxWxD)	192 x 140 x 89 mm
Country of Origin	USA

Precision Measurement Architecture

This monitor uses two independent channels to measure axial displacement accurately. Each channel processes eddy-current probe signals to determine both position and gap voltage. The precision input stage maintains a calibrated sensitivity of 200 mV/mil. This sensitivity ensures reliable readings across the standard measurement range.

Fault Detection and Channel Integrity

An integrated Not OK circuit actively monitors each transducer channel continuously. The system detects wire breaks, impedance faults, and sensor disconnections reliably. Upon detecting a probe failure, the monitor de-energizes the affected channel within 100 milliseconds. This rapid response prevents false alarm trips during transducer faults.

Flexible Output Configuration

You can field-select recorder output options to match your specific system requirements. The module supports 4-20 mA, 0 to -10 VDC, or +1 to +5 VDC outputs. This flexibility enables seamless integration with DCS, PLC, and SCADA platforms. Additionally, the non-multiplexing display shows both channels simultaneously.

Robust Environmental Performance

The module operates reliably across a wide industrial temperature range. Its compact 192 x 140 x 89 mm footprint saves valuable panel space. The lightweight 1.02 kg design facilitates easy installation and maintenance. Furthermore, the rugged construction withstands vibration and temperature fluctuations in plant environments.

Application Suitability

This thrust position monitor serves steam turbines, gas turbines, and compressors. It also protects large pumps, motors, and turbo-expanders effectively. Operators in power generation, oil and gas, and manufacturing industries rely on this module. The system’s proven reliability reduces unplanned downtime and extends machinery service life.