330171-00-20-05-02-00 Bently Nevada 5mm Probe 1/4-28

Product Overview of the 330171-00-20-05-02-00

The Bently Nevada 330171-00-20-05-02-00 is a 5 mm proximity probe engineered for exact displacement and vibration measurement in rotating machinery. As part of the trusted 3300 series, this probe features a 1/4-28 UNF thread and comes without armor. Its 0.5 meter total length and miniature coaxial ClickLoc connector make it a precise fit for tight installation spaces. The probe tip is constructed from polyphenylene sulfide (PPS), while the case uses AISI 304 stainless steel for durability.

Key Specifications and Performance Data

Every parameter of the 330171-00-20-05-02-00 is verified for engineering-grade accuracy. The probe operates with a -17.5 Vdc to -26 Vdc power supply, drawing a maximum of 12 mA. Sensitivity is less than 2 mV change per volt change in input voltage, ensuring stable signal output. The output resistance is 50 Ω, and the probe DC resistance from center to outer conductor is 7.45 ± 0.50 Ω at 0.5 m length. The probe cable is 75 Ω triaxial, FEP insulated. With a weight of 0.323 kg and a temperature range of -35°C to +177°C, this probe delivers reliable performance in harsh industrial environments.

Comparison with Similar Probes

When selecting a proximity probe, engineers compare thread size, cable length, and connector type. The 330171-00-20-05-02-00 offers a 1/4-28 UNF thread, which is common in many Bently Nevada systems, but its 0.5 m cable and miniature coaxial ClickLoc connector distinguish it from longer-cable variants. Unlike armored probes, this model is without armor, making it lighter and more flexible for applications where armor is unnecessary. The 5 mm tip diameter provides a balance between sensitivity and ruggedness, suitable for moderate shaft sizes. For exact matching to your system, always verify the probe's electrical characteristics against your Proximitor sensor requirements.

Installation and Integration Notes

Proper installation is critical for accurate measurements. The 330171-00-20-05-02-00 requires a mounting hole drilled and tapped for 1/4-28 thread; a #3 or larger tap drill is recommended. Maximum thread engagement is 0.375 in. The recommended probe case torque is 5.1 N·m (45 in·lb), with a maximum of 7.3 N·m (65 in·lb). The minimum cable bend radius is 25.4 mm (1.0 in) to prevent damage. When integrating into a monitoring system, ensure the power supply provides -17.5 Vdc to -26 Vdc. Operation at a more positive voltage than -23.5 Vdc can reduce linear range. The ClickLoc connector simplifies connection to extension cables and Proximitor sensors.

Maintenance and Reliability

To maintain engineering-grade precision, inspect the probe periodically for signs of wear, contamination, or loose connections. The PPS tip and stainless steel case resist many industrial chemicals, but exposure to temperatures below -34°C may cause premature pressure seal failure. Keep the connector clean and dry. Since the probe operates in a temperature range of -35°C to +177°C, ensure ambient conditions remain within these limits. Following these practices maximizes service life and measurement accuracy.