330851-02-000-066-10-00-CN Bently Nevada Probe

Product Overview

The 330851-02-000-066-10-00-CN is a heavy-duty 3300 XL 25 mm Proximity Probe assembly engineered by Bently Nevada for high-precision machine condition monitoring. Designed to measure static and dynamic displacements, this eddy current sensor is optimized for demanding turbomachinery setups requiring extended linear measurement ranges, such as axial thrust position or differential expansion on large steam turbines. It features a metric M30×2 fully threaded stainless steel case with an overall length of 66 mm, a 1.0-meter unarmored FluidLoc triaxial cable, and country-specific approvals (CN). Built with a specialized polyetheretherketone (PEEK) tip, this compact 0.38 kg sensor operates continuously in extreme temperature environments ranging from –35 °C to +200 °C.

Core Technical Advantages

Triaxial FluidLoc Moisture Barrier

The module is equipped with a 1.0-meter (3.3-ft) triaxial FluidLoc cable design. This engineering structure prevents process oils, high-pressure steam, or corrosive moisture from traveling through the internal jacket layers of the cable, protecting the sensitive coaxial connections and maintaining signal integrity over time.

Advanced PEEK Thermoplastic Tip Assembly

The sensor's tip is molded from high-performance polyetheretherketone (PEEK) engineering plastic. This material delivers excellent dimensional tracking stability, high dielectric strength, and extreme resistance against chemical corrosion, physical erosion, and structural tip wear (holding a tight tolerance of ±0.05 mm).

Extended Thermal and Mechanical Ruggedness

Housed in an AISI 304 stainless steel case, the probe survives continuous thermal exposure up to +200 °C, with a short-term survival window reaching +250 °C for up to 24 hours. Paired with a peak shock resistance rating of 1,000 g, the probe maintains an MTBF of 100,000 hours in severe operational environments.

Technical Specifications

Installation and Maintenance

Mechanical Threading and Clearance Check

Thread the M30×2 probe body into the mounting bracket or machine case housing port manually. Ensure that the 0-inch unthreaded case profile is correctly aligned with your target face. Verify that the clearance area around the 25 mm PEEK sensor tip matches the manufacturer's side-clearance standards to prevent crosstalk from adjacent metal structures. Note that the total weight supported by the mounting assembly will include the 0.38 kg hardware base plus any external junction fixtures.

Voltage Gap Calibration Mapping

Connect the 1.0 m unarmored triaxial cable tail to a matching 3300 XL 25mm Proximitor Sensor using a standard extension cable loop. Power the system and monitor the DC output voltage with a digital multimeter. Carefully adjust the probe's mechanical depth inside the M30 threading until the voltage reaches the specified mid-range linear gap calibration point before securing the locknuts.

Cable Dressing and Bend Radius Enforcement

Route the FluidLoc triaxial cable back to the junction box. Avoid sharp bends near the case transition, keeping the bend radius well within the specified limits for unarmored lines. Use insulated cable clamps to secure the line, ensuring it is isolated from heavy machinery vibrations that could cause physical wear over its 100,000-hour operational lifespan.

Engineering Advantages

Large Scale Turbomachinery Thrust Alignment

The 25 mm eddy current tip configuration offers a much wider linear range than standard 8 mm probes. This expanded capability makes it an ideal option for tracking large physical movements, such as shaft differential expansion, case expansion, and heavy structural thrust tracking on utility-scale steam generator shafts.

High Ingress Protection Against Process Fluids

The combination of the hermetically bonded PEEK tip and the FluidLoc internal cable block allows the probe assembly to withstand wet environments. It prevents pressurized synthetic oils, chemical liquids, or process gases from leaking along the cable into the clean instrumentation enclosures.

Compliant Certification Footprint

The CN suffix confirms that the module complies with country-specific safety frameworks and hazardous area standards. This certification streamlines compliance approvals for engineering procurement companies (EPCs) during major plant construction and retrofitting projects.

Technical FAQs

Q1: Why does a 25 mm proximity probe require a larger M30 diameter case body?
A1: The larger 25 mm sensor tip houses a larger internal coil assembly, which is required to generate the deeper magnetic field needed for an extended linear measurement range. The M30×2 thread provides the structural strength and space required to mount this larger high-range sensing element safely.

Q2: Can this unarmored cable version be routed through open machinery paths?
A2: While the triaxial FluidLoc cable is highly rugged and resists fluid migration, this specific configuration lacks a flexible stainless steel outer armor sleeve. For open routing paths exposed to falling debris or maintenance traffic, it should be protected within a dedicated conduit pipe or cable tray.

Q3: What are the risks if the sensor tip exceeds the +250 °C short-term peak limit?
A3: Exceeding the +250 °C limit can soften or deform the PEEK tip material. This can alter the mechanical position of the internal coil or cause a loss of the hermetic seal, leading to signal drift, electrical shorting, or permanent damage to the proximity sensor module.