Product Overview

The Bently Nevada 330704-000-100-10-01-05 is a high-reliability 3300 XL 11 mm Proximity Probe designed for critical machinery protection systems (MPS) and continuous turbo-machinery condition monitoring. Operating on advanced eddy current principles, this non-contacting sensor provides precise physical displacement and dynamic vibration measurements of rotating shafts. It serves as an essential instrumentation element for critical machinery monitoring, specifically where standard 8 mm probe systems lack the required linear range or physical clearance.

By utilizing an upgraded 11 mm tip diameter, this probe yields an extended linear range of 4.0 mm (160 mils), which is double the measurement envelope of conventional 8 mm sensors. This makes it highly effective for tracking large shaft thermal movements, axial thrust displacement, and differential expansion in high-capacity rotating machinery.

This specific metric configuration features an M14 x 1.5 threaded body with a 0 mm unthreaded length, a 100 mm overall case length, a 1.0-meter integrated coaxial cable wrapped in rugged stainless steel armor, and a specialized ClickLoc miniature coaxial connector. Complete with multi-agency hazardous area approvals, it integrates directly with the Bently Nevada 3500/42M Proximitor Seismic Monitor or legacy 3300 series vibration racks via a matching 3300 XL 11 mm extension cable and Proximitor sensor loop.

Technical Specifications

Model Configuration Explanation

The product nomenclature 330704-000-100-10-01-05 defines the explicit structural configuration of the 3300 XL 11 mm metric probe:

• 330704: The fundamental base model identifier for the 3300 XL 11 mm Proximity Probe with standard metric threads (M14 x 1.5).
• 000: Unthreaded Length Option. Specifies 0 mm of unthreaded body. The entire case length is fully threaded, maximizing positioning flexibility within mounting brackets.
• 100: Overall Case Length Option. Signifies a 100 mm total case length, designed to pass safely through deep machinery casings or thick bearing housings.
• 10: Total Length Option. Dictates a 1.0-meter (3.3 feet) integrated probe cable length, optimal for routing from the machine core out to an external junction box.
• 01: Connector and Cable Option. Features a miniature coaxial ClickLoc connector coupled with flexible stainless steel armor running the full length of the cable to resist physical tearing and chemical degradation.
• 05: Agency Approval Option. Multiple Approvals certification package. This verifies intrinsic safety (IS) and non-incendive status under ATEX, IECEx, and North American CSA frameworks for deployment in Zone 0, 1, 2, and Class I, Division 1 or 2 hazardous process environments.

Typical Applications

The 330704-000-100-10-01-05 probe is primarily deployed in high-speed, high-consequence turbo-machinery where precise mechanical tolerances are vital to process safety and uptime:

• Steam and Gas Turbines: Continuous tracking of axial thrust position and shaft radial vibration to prevent high-speed internal rotor-to-stator rubbing.
• Centrifugal Compressors: Real-time orbit analysis, cross-axis vibration monitoring, and oil-film bearing stability assessments.
• Rotor Expansion Tracking: Monitoring Differential Expansion (DE) where the relative thermal growth discrepancy between the heavy casing and the rotating shaft exceeds the measurement limits of small-scale 8 mm sensors.
• Hydroelectric Generators: Measuring structural shaft runout, low-frequency structural wobble, and rotor eccentricity during cold start and synchronization phases.
• Industrial Gearboxes: Dynamic vibration measurement of input and output shafts under extreme torsional loads within chemical and petrochemical processing lines.

System Compatibility

The 330704-000-100-10-01-05 probe cannot operate as a standalone sensor. To comply with API 670 industry standards for machinery protection, it must be paired with specific, calibrated matching components:

• Extension Cable Compatibility: Must be matched with a 3300 XL 11 mm Extension Cable (such as the 330730 series). The combined length of the probe cable (1.0m) and the extension cable must total either exactly 5.0 meters or 9.0 meters.
• Proximitor Sensor Compatibility: Requires connection to a 3300 XL 11 mm Proximitor Sensor (Model 330780). This sensor provides the radio frequency (RF) signal to the probe tip and rectifies the return signal into a linear DC voltage.
• Monitoring Rack Integration: Connects seamlessly with the Bently Nevada 3500/42M Proximitor Seismic Monitor module or classic 3300/20 dual-vibration monitors, enabling automatic alarm generation, alert relay trips, and Modbus/Ethernet communication to the distributed control system (DCS).

Mechanical Installation Guidelines

• Target Surface Condition: Ensure the shaft target area has a surface finish of 0.8 micrometers (32 microinches) Ra or better, and is completely free of deep scratches, machining grooves, or chrome plating, which can distort eddy current readings.
• Setting the Gap Voltage: Mount the probe using an isolation bushing or bracket. Connect a digital multimeter to the "BUF" output terminal of the Proximitor Sensor and turn the probe into the mounting thread until the gap voltage reads approximately -10.0 Vdc. This places the probe precisely at the center of its 4.0 mm linear operating range.
• Clearance Around the Tip: To avoid side-loading or "false target" interference from surrounding metal walls, maintain a counterbore diameter of at least 38 mm (1.5 inches) around the exposed 11 mm probe tip.
• Preventing Cross-Talk: If installing two probes in an X-Y orthogonal configuration, ensure a minimum physical separation distance of 40 mm (1.6 inches) between the probe tips to eliminate mutual electromagnetic field interference.
• Securing the Installation: Once the mechanical gap is verified via voltage readings, tighten the M14 locknut to a maximum torque of 22.6 N·m (200 in·lb). Thread a high-grade stainless steel safety wire through the integrated locknut holes and tie it back to the bracket to prevent mechanical loosening caused by continuous high-frequency machine vibration.

Product Advantages

• Expanded Measurement Envelope: The 11 mm probe tip generates a broader electromagnetic field, delivering a full 4.0 mm linear range. This minimizes the risk of the probe going out-of-range during extreme thermal growth or heavy thrust load conditions.
• ClickLoc Coaxial Connection: Equipped with gold-plated brass connections that require no special tools to terminate. The positive-locking design eliminates intermittent contact issues and resists high industrial vibration.
• Extreme Structural Durability: Utilizes patented TipLoc molding to chemically bond the probe tip to the stainless steel body, along with CableLoc construction to provide 330 N of continuous cable pull-strength relief.
• Integrated Armor Shell: The flexible, fluid-tight stainless steel armor protects the delicate internal coaxial line against pinching, sharp metal shavings, hot oil baths, and synthetic lubricants common in bearing housings.
• True Component Interchangeability: Manufactured to strict physical and electrical tolerances, enabling direct drop-in replacement of individual probes, cables, or sensors without tedious system re-calibration.

Ordering Information

Procurement Note: For new installations or total loop replacements, please verify if your loop configuration requires a 5.0-meter or 9.0-meter system, and purchase the corresponding 3300 XL 11 mm Extension Cable and Proximitor Sensor along with this probe.

Logistics and Shipping

To protect high-precision industrial instrumentation from transit damage and environmental stress, all items follow standardized industrial packaging rules:

Professional Packaging Protocol:

Every Bently Nevada 330704 probe is sealed inside an anti-static industrial packaging shield to fully isolate internal eddy-current components from static discharge (ESD). The entire assembly—including the armored cable—is secured in custom-cut, shock-absorbing high-density foam lines to prevent compression, bending, or shifting during global transit. Each shipment arrives complete with original material traceability logs and a factory Certificate of Conformance (CoC).

Frequently Asked Questions

• Can I use an 11 mm proximity probe with a standard 8 mm Proximitor sensor?

  No. The 11 mm probe operates at a completely different RF tuning frequency and requires the specific calibration profile of a 3300 XL 11 mm Proximitor Sensor (Model 330780). Mixing 8 mm and 11 mm components will result in severe scale factor errors and will prevent the monitoring system from functioning correctly.

• What does the "000" option indicate regarding the unthreaded length?

  The "000" option means the probe body has 0 mm of unthreaded length. The entire 100 mm stainless steel case is fully threaded with M14 x 1.5 threads from the base to the tip, allowing for maximum adjustable depth inside your mounting bracket.

• What is the standard scale factor of this probe system when fully assembled?

  The nominal scale factor is 3.94 V/mm (100 mV/mil). This means that for every 1 mil (0.001 inches) or 0.0254 mm of physical shaft movement toward or away from the probe tip, the output voltage signal shifts by exactly 100 mV.

• Why is the cable armor option ("01") recommended for turbomachinery installations?

  The stainless steel armor protects the inner coaxial cable from physical damage caused by routing through sharp metal conduit paths, concrete trenches, and areas exposed to flying debris, hot oils, and corrosive process chemicals.

• How do I troubleshoot an "I/O OK Fault" on a 3500 monitor paired with this probe?

  Check the DC gap voltage at the Proximitor sensor or monitor backplane. If the voltage reads close to 0 Vdc (short circuit) or near -24 Vdc (open circuit), look for physical cuts in the armored cable, loose or contaminated ClickLoc coaxial connections, or incorrect probe gapping.

• Is field calibration required when replacing a damaged 330704 probe?

  No. All Bently Nevada 3300 XL 11 mm system components are fully interchangeable. You can replace a damaged probe with a new one of identical options without performing bench calibration, provided the total system loop length (5m or 9m) remains unchanged.

• What target material is this specific probe factory-calibrated for?

  The probe is calibrated for AISI 4140 electric steel targets. If your machine features a shaft made of other alloys, stainless steel, or chrome-plated finishes, the scale factor must be compensated or custom-calibrated to ensure measurement accuracy.

• What hazardous area environments is the "05" approval option certified for?

  The "05" multi-approval choice combines ATEX, IECEx, and CSA standards into a single option. It allows the probe to be safely deployed in intrinsically safe, non-incendive configurations across Zone 0, Zone 1, Zone 2, and Class I, Division 1 or 2 environments globally.