Description

Engineered for highly precise displacement and vibration monitoring, the Bently Nevada 330101-00-28-20-02-00 is an unarmored 8 mm proximity probe designed for non-contact shaft position measurements. This specific configuration features a 3/8-24 UNF threaded body, an unthreaded length of 0.0 inches (representing a fully threaded case), a 2.8-inch overall case length, and a 2.0-meter total cable length. It terminates with a miniature coaxial ClickLoc connector and is designed for standard electrical configurations where specialized hazardous area agency approvals are not required.

Working on the eddy-current operating principle, this probe measures static and dynamic distance between the probe tip and a conductive target, typically an AISI 4140 steel shaft. It interfaces directly with a 3300 XL extension cable and Proximitor sensor, providing a highly stable voltage output proportional to the gap. This setup is highly reliable for measuring shaft vibration, position, and speed in critical rotating machinery, including steam turbines, compressors, and high-speed pumps. The unarmored design offers excellent flexibility in protected machinery casings, and its standard FEP-insulated coaxial cable provides robust resistance against industrial fluids, oils, and moisture.

Features

• Eddy-current non-contact measurement for machinery protection and condition monitoring.
• Fully threaded 2.8-inch case (0.0 inches unthreaded length) with standard 3/8-24 UNF threads.
• 2.0-meter total cable length, optimized for clean integration into machinery cable routing paths.
• Standard FEP insulated cable jacket with high resistance to harsh industrial chemicals and lubricants.
• Gold-plated miniature coaxial ClickLoc connector ensures a reliable, click-verified connection.
• Excellent mechanical interchangeability without requiring specialized bench calibration.

Applications

The probe is widely deployed in heavy machinery environments, including:

• Shaft radial vibration and axial position monitoring in steam and gas turbines.
• Rotor dynamic studies and casing expansion measurements.
• Displacement measurements in high-speed centrifugal compressors and pumps.
• Keyphasor and speed measurement on rotating shafts.
• Industrial machinery protection systems adhering to the API 670 standard.

Ordering Information

Technical Specifications

Installation Guidelines

To ensure precise vibration measurements, follow these engineering practices when installing the proximity probe:

• Mount the probe securely using appropriate bracketry to prevent structural resonance from affecting displacement readings.
• Ensure the target material is AISI 4140 steel, as the transducer system is calibrated to this metallurgical standard. Calibration shifts may occur with alternative metals.
• Set the proper probe gap (typically 1.27 mm or 50 mils) corresponding to the midpoint of the linear output range (-10 Vdc nominal) on the Proximitor sensor output.
• Strictly observe the minimum cable bend radius of 25.4 mm (1.0 inch) to prevent internal coaxial shielding damage.
• Run all field wiring using 3-conductor shielded triad cables, ensuring proper shielding and grounding configurations to minimize electro-magnetic interference (EMI).
• Do not exceed the maximum case thread tightening torque of 11.2 N-m (100 in-lbf) during installation.