330191-00-08-90-00 Bently Nevada 3300 XL 8 mm Proximity Probe

Introduction: The Evolution of Precision Measurement

For decades, industrial machinery has grown faster, hotter, and more demanding. Consequently, engineers needed measurement tools that could keep pace. The Bently Nevada 3300 XL series emerged from this need, representing a significant leap in eddy current proximity probe technology. Specifically, the 330191-00-08-90-00 model embodies this evolution. It is a 3300 XL 8 mm ETR probe, designed for exact displacement and vibration monitoring. This probe features a 3/8-24 UNF thread and a 9.0 meter total length. Furthermore, it comes without armor, offering flexibility for specific installation geometries. Therefore, when you require engineering-grade precision for critical turbomachinery, this probe delivers verified performance.

330191-00-08-90-00 Technical Specifications

The 330191-00-08-90-00 operates on a negative voltage supply, a standard for Bently Nevada proximity systems. It requires -17.5 Vdc to -26 Vdc when installed with a nonincendive circuit per installation drawing 140979. Maximum consumption is 12 mA. For barrier installations, the supply range is -23 Vdc to -26 Vdc. Notably, operation at a more positive voltage than -23.5 Vdc can reduce the linear range. The probe's output resistance is 50 Ω. Additionally, the nominal probe DC resistance (RPROBE) from center conductor to outer conductor is 9.87 ± 0.50 Ω for the 9.0 m length. The probe tip is made of polyphenylene sulfide (PPS), and the case is AISI 303 or 304 stainless steel. The standard cable is 75 Ω triaxial, FEP insulated. The connector material is gold-plated brass or gold-plated beryllium copper, with a maximum connector torque of 0.565 N•m (5 in•lbf).

Key Features and Engineering Advantages

• Patented TipLoc Molding: Provides a robust bond between probe tip and body.
• CableLoc Design: Delivers 330 N (75 lbf) pull strength for secure cable attachment.
• 8 mm Probe Diameter: Offers thicker encapsulation for ruggedness against physical abuse.
• Differential Pressure Seal: Viton® O-ring seals between probe tip and case.
• Temperature Range: Operates from -55°C to +232°C depending on T-class.

Installation and Compatibility

Installing the 330191-00-08-90-00 requires attention to thread engagement. The 3/8-24 UNF thread has a maximum engagement length of 0.563 in. The probe has a minimum unthreaded length of 0.0 in. and a minimum case length of 0.8 in. For one-meter systems, no extension cable is used. However, this 9.0 m probe typically pairs with an extension cable and a Bently Nevada proximitor. The probe entity parameters are met when used with BN extension cables and connected to BN Prox. Therefore, always verify compatibility with your existing monitoring system.

Applications and Use Cases

The 330191-00-08-90-00 excels in harsh industrial environments. For instance, it monitors radial vibration on steam turbines. Additionally, it measures axial position on centrifugal compressors. Because of its 8 mm diameter, it withstands physical abuse better than smaller probes. Consequently, it is ideal for installations where probe damage is a risk. Furthermore, the ETR (Extended Temperature Range) cable option allows operation in higher ambient temperatures. This makes it suitable for gas turbines and other high-temperature machinery.

Maintenance and Reliability

To ensure long-term reliability, inspect the probe periodically for physical damage. Check the cable for cuts or abrasions. Verify the connector torque does not exceed 0.565 N•m. Since the probe seals differential pressure with a Viton® O-ring, inspect for leaks if process fluid is present. However, do not disassemble the probe. Instead, follow the manufacturer's safety manual for all maintenance. With proper care, the 330191-00-08-90-00 provides years of precise measurement.