330908-10-55-05-02-00 Bently Nevada 3300 NSv Eddy Current Probe

Product Overview

The 330908-10-55-05-02-00 is a high-precision 3300 NSv proximity probe manufactured by Bently Nevada, designed for critical vibration and position monitoring in confined spaces. This eddy current sensor features a 3/8-24 UNF unarmored thread configuration with an unthreaded length of 1.0 inch and an overall case length of 5.5 inches. Weighing approximately 0.14 kg (0.31 lbs), its lightweight yet rugged construction provides superior side-view characteristics and enhanced chemical resistance, effectively replacing older 3300 RAM and 3000-series 190 probes in centrifugal compressors, pumps, and high-speed rotating machinery.

Suffix Configuration Breakdown

• 330908: 3300 NSv Proximity Probe standard model, 3/8-24 UNF thread, without armor.
• -10: Unthreaded case length of 1.0 inch.
• -55: Overall case length of 5.5 inches.
• -05: Total electrical cable length of 0.5 meters (20 inches).
• -02: Miniature coaxial ClickLoc connector with standard FEP insulated cable.
• -00: Standard option, no specific agency approvals required.

Technical Specifications

Installation & Maintenance

• Gap Voltage Target: Set the initial physical gap to 1.0 mm (40 mils) during installation, which corresponds to the midpoint of the linear output voltage slope (approx. -9 Vdc).
• Torque Constraints: Tighten the probe case to a recommended 11.3 N·m (100 in·lb), never exceeding the maximum rating of 33.9 N·m (300 in·lb). Connectors should be joined finger-tight to a maximum of 0.56 N·m (5 in·lb).
• Cable Bend Radius: Maintain a minimum bend radius of 25.4 mm (1.0 inch) along the 75 Ω coaxial FEP insulated cable to prevent core deformation and signal attenuation.
• Target Diameter Limits: Ensure a flat target diameter of at least 13 mm (0.5 in). Targets below 8.9 mm (0.35 in) alter the scale factor and require a reduced physical gap.

Engineering Advantages

• Advanced Chemical Resilience: The PPS tip construction offers premium protection against corrosive process gases, enabling direct deployment inside aggressive compressor environments.
• Tight Space Optimization: The unique side-view design and low mass profile reduce cross-talk and structural interference errors when gapping close to machine counterbores or casing walls.
• Backward Compatibility: Integrates directly with existing 3300 RAM system footprints, providing an immediate upgrade path without replacing existing infrastructure.

Technical FAQs

Q1: What extension cable and field wiring should be paired with this probe?
A1: Use a matching 3300 NSv extension cable. For field wiring to the monitor (up to 305 meters), a three-conductor shielded triad cable between 0.2 to 1.5 mm² (16 to 24 AWG) is highly recommended.

Q2: Is the pressure seal of the 330908 probe factory-tested prior to shipping?
A2: No. While the integrated Viton O-ring is engineered to seal differential pressure between the tip and case, these probes are not pressure-tested before shipment unless explicitly requested via custom design orders.

Q3: How does a target shaft smaller than the recommended 13 mm alter performance?
A3: Shafts smaller than 13 mm (0.5 in) reduce the visible target area, causing a shift in the Incremental Scale Factor (ISF). You can mitigate this scale factor deviation by reducing the operational gap distance between the probe tip and the shaft target.