330172-20-55-05-02-CN | Bently Nevada 5mm Probe, 1/4-28 UNF

Product Overview: Bently Nevada 330172-20-55-05-02-CN

When your rotating machinery demands exact displacement data, the Bently Nevada 330172-20-55-05-02-CN delivers engineering-grade precision. This 3300 series 5mm probe features a 1/4-28 UNF thread and armored construction. Consequently, it suits harsh industrial environments where mechanical integrity is non-negotiable. The probe operates with a -24 Vdc power supply and a 10 kΩ load, providing a 50 Ω output resistance. Moreover, its polyphenylene sulfide (PPS) tip and AISI 304 stainless steel case ensure durability. As a result, you get reliable performance across a probe temperature range of -35°C to +177°C.

Key Specifications of the 330172-20-55-05-02-CN

• Input Voltage: Requires -17.5 Vdc to -26 Vdc at 12 mA maximum consumption.
• Output Resistance: 50 Ω for stable signal transmission.
• Isolation: Probe DC resistance from center to outer conductor is 7.45 ± 0.50 Ω at 0.5 m length.
• Probe Tip Material: Polyphenylene sulfide (PPS) for chemical resistance.
• Case Material: AISI 304 stainless steel (SST) with armor.
• Thread: 1/4-28 UNF, maximum engagement 0.375 in.
• Total Length: 0.5 meter (1.6 feet).
• Weight: 0.323 Kg.

Notably, the miniature coaxial ClickLoc connector ensures a secure, repeatable interface. Additionally, the probe's sensitivity is less than 2 mV change per volt change in input voltage, minimizing supply-induced errors.

Installation and Setup

Proper installation begins with drilling and tapping a 1/4-28 mounting hole. A #3 or larger tap drill is recommended. Then, apply the recommended probe case torque of 5.1 N·m (45 in·lb), never exceeding 7.3 N·m (65 in·lb). Furthermore, maintain a minimum cable bend radius of 25.4 mm (1.0 in) to prevent damage. Because the probe uses a -24 Vdc supply, verify polarity and voltage before power-up. Operation at a more positive voltage than -23.5 Vdc can reduce linear range. Therefore, always confirm your supply meets the -17.5 Vdc to -26 Vdc window.

Reliability and Maintenance

To ensure long-term reliability, inspect the probe periodically for mechanical wear or cable damage. The armored case protects against abrasion, but the connector and cable remain vulnerable. Also, avoid exposing the probe to temperatures below -34°C (-30°F), as this may cause premature pressure seal failure. Given its 222 N (50 lbf) tensile strength, the probe withstands moderate pulling forces. However, always route cables away from high-vibration areas. For engineering-grade accuracy, verify probe gap and target material (AISI 4140 steel) during scheduled maintenance.