Configured for radial and axial shaft displacement monitoring in Bently Nevada 3300 NSv series machinery protection systems, the Bently Nevada 330908-00-36-05-02-05 (330908 Proximity Probe) provides direct eddy-current proximity measurement for rotating machinery.

Suffix Breakdown & Model Matrix

Hardware Specifications

Cross-Talk Suppression & Signal Integrity

The 330908 NSv probe incorporates a coaxial ClickLoc connector interface that provides inherent electromagnetic shielding for the RF signal path between the probe tip and the signal conditioner. The 3/8-24 UNF thread form offers increased mechanical engagement depth compared to the 1/4-28 UNF variant, providing higher resistance to vibration-induced loosening in high-speed rotor applications. The 3.6 in case length positions the sensing element further from the mounting face, enabling measurement access in deep-bore or recessed mounting scenarios. Gap voltage validation targets -10 VDC at mid-scale. The coaxial cable construction maintains characteristic impedance matching across the full cable length, minimizing signal reflection and phase shift that could compromise measurement accuracy in high-frequency eddy-current excitation circuits.

Ordering Info

• 1 x 330908-00-36-05-02-05 Proximity Probe (unarmored, 3/8-24 UNF, 3.6 in case, 0.5 m cable, ClickLoc connector, Multiple Approvals)

Field Installation Guidelines

• Verify probe tip is free of debris and damage before installation.
• Engage a minimum of 5 full threads of the 3/8-24 UNF fitting into the probe bracket or housing.
• Tighten to specified torque (refer to 3300 NSv system manual); the larger 3/8-24 thread requires appropriate torque values distinct from 1/4-28 applications.
• Ensure the probe tip does not contact the rotating shaft at any position throughout the full operating range.
• Route the coaxial cable away from high-voltage conductors and switching devices to minimize EMI.
• Terminate the cable shield at the signal conditioner end only (single-point ground) to prevent ground loops.
• Confirm the ClickLoc connector is fully seated and the locking mechanism is engaged.
• Verify Multiple Approvals markings are visible and match installation site hazardous area classification.

Frequently Asked Questions

• Q: What is the difference between the 330908 and 330901 NSv probe models?

  A: The 330908 uses a 3/8-24 UNF thread and is typically specified for applications requiring deeper case lengths. The 330901 uses a 1/4-28 UNF thread. Both operate on the same eddy-current principle with identical scale factors.

• Q: What is the nominal gap voltage target for this probe during calibration?

  A: The standard gap voltage target is -10 VDC at the transducer output when the probe is positioned at the mid-scale gap distance from the target surface.

• Q: Can this probe be used with 3300 XL series extension cables?

  A: No. The 330908 NSv probe uses a miniature coaxial ClickLoc connector and is designed specifically for the 3300 NSv system. It is not compatible with 3300 XL extension cables.

• Q: What is the linear measurement range of the 330908 probe?

  A: The linear range is approximately 80 mils (2.03 mm) total, with a scale factor of 200 mV/mil. The usable range may vary slightly based on target material properties.

• Q: What target materials are compatible with this eddy-current probe?

  A: The probe is calibrated for ferrous and non-ferrous conductive materials. Standard calibration targets are 4140 steel. Different materials will produce different scale factors.

• Q: What does "Multiple Approvals" indicate for this probe?

  A: Multiple Approvals indicates the probe meets certification standards for installation in hazardous areas under various agency classifications. Verify specific approval codes against site requirements before installation.

• Q: What is the function of the ClickLoc connector locking mechanism?

  A: The ClickLoc connector provides a secure, vibration-resistant connection that prevents accidental disengagement due to machinery vibration. Always verify the lock is fully engaged after connection.

• Q: Can this probe be hot-swapped while the system is operational?

  A: No. The probe and its signal conditioner should be installed and wired with the system de-energized. Verify gap voltage and signal integrity after installation before returning to service.