The Bently Nevada 330706-005-046-10-02-00 is a specialized 11mm reverse mount proximity probe engineered for the most demanding Turbine Supervisory Instrumentation (TSI) applications. While standard 8mm probes satisfy general vibration needs, this 11mm system provides a significantly extended linear range, making it the premier choice for monitoring axial thrust position and differential expansion in large steam turbines and reciprocating compressors. Its "Reverse Mount" design allows for internal installation within machine housings where external access is limited or where traditional probe mounting is mechanically impossible.
This transducer captures microscopic shaft movements without physical contact, providing essential protection for fluid-film bearing machinery. By tracking axial thrust and rod drop in real-time, the 330706 probe prevents catastrophic shaft rubbing and bearing failure. Its specialized 100 mV/mil (3.94 V/mm) output delivers high-fidelity displacement data, allowing plant engineers to maintain continuous oversight of their most critical rotating assets in power generation and hydrocarbon processing environments.
The model 330706-005-046-10-02-00 follows a specific Bently Nevada engineering nomenclature where each digit segment dictates a mechanical or electrical requirement:
The 005 designates an unthreaded length of 0.5 inches. This configuration allows for specific penetration into the bearing housing while ensuring the threaded portion remains secured within the mounting bracket or standoff.
This indicates an overall case length of 4.6 inches. The reverse mount probe utilizes a specialized housing that allows the cable to exit through the probe tip side or a side port, facilitating internal machine mounting.
The 10 specifies a 1.0-meter (approx. 3.3 feet) total system length. This probe must be paired with the correct 3300 XL 11mm extension cable to match the Proximitor sensor's total calibrated length (e.g., 5.0m or 9.0m) to maintain signal linearity.
The 02 option provides a miniature coaxial ClickLoc connector with a connector protector to prevent oil and fluid ingress. The -00 signifies standard global agency approvals, certifying the unit for safe operation in industrial environments.
| Feature | Specification Details |
| Probe Tip Diameter | 11.0 mm (0.433 in) |
| Linear Range | 4.0 mm (160 mils) |
| Nominal Sensitivity (ISF) | 3.94 V/mm (100 mV/mil) |
| Operating Temperature | -51 °C to +177 °C (-60 °F to +351 °F) |
| Target Material | AISI 4140 Steel (Standard Calibration) |
| Pressure Rating | Sealing up to 70 psi (4.8 bar) |
| System Length | 1.0 Meter (Probe only) |
| Compliance | API 670 Standard |
Reliable machinery protection starts with precise sensor gapping and meticulous cable management during the installation process:
Engineers must set the initial "Static Gap" using a Digital Multimeter (DMM). For a 3300 XL 11mm system, the center of the 160-mil linear range corresponds to -10.0 VDC. Adjust the probe depth within the reverse mount housing until the Proximitor output reaches this value while the shaft remains at its rest position before locking the assembly.
The reverse mount probe installation typically occurs from the inside of the machine housing. Ensure that the cable routing provides sufficient strain relief and avoids contact with rotating components. Use the ClickLoc connector protector to prevent oil from the bearing housing from entering the coaxial connection.
The 11mm probe is sensitive to surface imperfections like scratches or rust. Ensure the target area on the shaft has a smooth surface finish (typically 0.8 micrometers or better). If the target material is not AISI 4140 steel, the sensitivity must be field-verified or recalibrated within the 3500 Monitoring System software.
Extended Measurement Range: The 11mm tip provides 160 mils of linear range, double that of standard 8mm probes, making it ideal for high-displacement axial measurements.
TSI Seamless Integration: This probe interfaces directly with the Bently Nevada 3500 series monitors, ensuring immediate data visualization in System 1 software for comprehensive diagnostics.
Superior PPS Tip Construction: The probe tip utilizes Polyphenylene Sulfide (PPS), a high-performance thermoplastic that resists chemical corrosion and maintains structural integrity across extreme thermal cycles.
Legacy Compatibility: This module serves as a modern, reliable replacement for discontinued 7200-series transducer systems, bringing legacy machines up to modern API 670 standards.
Q1: How do I verify the health of the 330706 probe?
A1: Measure the DC resistance between the center pin and the outer shield of the coaxial connector. A healthy 1.0m probe lead typically reads between 5.0 Ω and 9.0 Ω. An infinite reading indicates an open circuit, requiring probe replacement.
Q2: Can I use this probe with an Ethernet router?
A2: No. This is a common clerical error in logistics databases. The 330706 is a passive analog sensor. Digital networking (Ethernet) occurs at the 3500 Monitoring Rack level, not at the probe.
Q3: Can I mix 11mm probes with 8mm extension cables?
A3: No. 11mm systems utilize different electrical calibrations and physical connector dimensions. You must use 3300 XL 11mm probes with 11mm extension cables and 11mm Proximitors to maintain the correct 100 mV/mil sensitivity.
Q4: Is this probe compatible with older 3300 series monitors?
A4: Yes. The 3300 XL 11mm system maintains backward compatibility with legacy 3300 monitors. However, for maximum accuracy and noise immunity, we recommend using a complete 3300 XL transducer system integrated into a 3500 series rack.
