Product Description

Overview

The Bently Nevada 3300/20-12-01-02-03-02 is a dual-channel thrust position monitor engineered for legacy 3300 machinery protection systems. It continuously measures the axial displacement of rotating shafts, providing early detection of potential shaft excursions that could cause contact between rotating and stationary components. This module is essential for safeguarding turbines, compressors, and other critical machinery against axial misalignment or thrust bearing failures.

Key Features

• Dual Channel Monitoring: Supports independent or redundant thrust measurements for enhanced reliability.

• Directional Measurement: Displays shaft movement "Toward" or "Away" from the sensor.

• Configurable Alarm Logic: AND/OR relay logic allows 2-out-of-2 or independent channel voting for “Danger” alarms to reduce false trips.

• Real-Time Display: Front-panel LCD provides digital readings and bar graphs for both channels.

• System Integrity Monitoring: Detects open/short circuits and out-of-range transducer voltages.

• First Out Identification: Tracks which channel first exceeded an alarm threshold.

Technical Specifications

Input

• Signal: Two 3-wire Proximitor sensors

• Input Impedance: 10 kΩ

• Sensitivity: 200 mV/mil (8 V/mm)

Output

• Recorder Output: 4–20 mA proportional to thrust position

• Buffered Output: Raw DC/AC signals via front-panel coaxial connectors

• Relays: Hermetically-sealed Alert and Danger, independent or shared

• Contact Rating: 5A @ 120/240 Vac or 5A @ 28 Vdc

Performance

• Accuracy: ±1% of full-scale range at +25°C

• Full Scale Range: ±40 mils (±1.0 mm typical)

• System OK Monitoring: Detects transducer faults and out-of-range signals

Environmental

• Operating Temperature: 0°C to +65°C (+32°F to +150°F)

• Storage Temperature: -40°C to +85°C (-40°F to +185°F)

• Relative Humidity: Up to 95%, non-condensing

• Power: 120 Vac nominal, 1.5 W typical

Physical Dimensions

• Size: 240 mm × 480 mm × 100 mm

• Weight: 1 kg

Signal Processing Features

• Zeroing: Electronic zero adjustment at a specific shaft position

• Alarm Delays: 1–60 second programmable delay for sustained event detection

• First Out Function: Identifies the channel that first violates the alarm threshold

Applications

Ideal for axial position monitoring in turbines, compressors, pumps, and large rotating machinery. Supports predictive maintenance programs by providing early warning of abnormal axial movement, preventing catastrophic failure and reducing unplanned downtime.

FAQ

Q: Can the 3300/20 monitor single or dual channels?
A: It supports two independent channels, configurable for redundant or separate thrust monitoring.

Q: What is the purpose of AND/OR logic in alarms?
A: It allows “Danger” alarms to require both channels to exceed the threshold, reducing false trips during transient events.

Q: Is this product compatible with modern Bently Nevada systems?
A: As a legacy 3300 series module, it is compatible with existing 3300 racks. For new installations, Bently recommends the 3500/40M or 3500/42M Proximitor Monitors.