330851-08-000-064-10-01-05 Bently Nevada 25mm Side-Exit Probe

Product Overview

The 330851-08-000-064-10-01-05 is a specialized 3300 XL 25 mm Proximity Probe manufactured in the United States by Bently Nevada. This high-reliability eddy current transducer is engineered to physically replace legacy 7200 25 mm, 7200 35 mm, and 25 mm Differential Expansion (DE) Integral sensor systems in tight clearances. This specific configuration features a non-threaded, unthreaded smooth 1.5-inch diameter case with a side exit cable orientation and a 64 mm overall case length. Outfitted with a 1.0-meter PFA-insulated FluidLoc triaxial cable enclosed in a rugged stainless steel (SST) flexible armor sleeve, this 0.33 kg (330 grams) sensor is optimized for high-vibration thrust and expansion monitoring inside heavy utility steam turbines.

Core Technical Advantages

Side-Exit Cable with Stainless Steel Armor

The module is designed with a side-exit cable layout that significantly reduces the axial clearance space required behind the sensor body. Protected by a flexible stainless steel (SST) armor sleeve, the 1.0-meter lead withstands mechanical abrasion, pinch points, and flying debris within busy machine casings while maintaining an installed weight of 0.33 kg.

Advanced FluidLoc Moisture Isolation

The internal 75-ohm triaxial cable features perfluoroalkoxyethylene (PFA) insulation layered with Bently Nevada’s proprietary FluidLoc blocking technology. This structural configuration prevents pressurized synthetic lubrication fluids, condensation, and process gases from wicking through the cable jacket into clean connection enclosures.

High-Performance PEEK Tip Molding

The 25 mm probe head is molded from premium Polyetheretherketone (PEEK) thermoplastic. This material provides exceptional physical stability, high dielectric isolation, and excellent immunity against chemical corrosion, moisture erosion, and airborne oil mist particles inside high-temperature turbine environments.

Technical Specifications

Installation and Maintenance

Smooth Case Bracket Clamping

Unlike threaded alternatives, the smooth 1.5-inch diameter case requires a split-collar mounting bracket or bore clamp fixture. Slide the 64 mm AISI 304 stainless steel body into the clamp block assembly. Position the side-exit cable carefully to align with your routing track, ensuring the armored wire is free from tension or binding points before securing the clamp hardware.

Proximitor Calibration and Voltage Gapping

Connect the 1.0 m armored triaxial terminal to your 3300 XL 25mm Proximitor Sensor using an extension cable link. Apply system power and monitor the output DC voltage. Manually adjust the depth of the 0.33 kg probe body inside its smooth mounting sleeve until your multimeter reads the designated mid-range linear gap tracking voltage, then lock the mounting bracket firmly.

Hazardous Location Safety Compliance

When operating in hazardous areas matching the Option 05 certification block, review all referenced control drawings. For intrinsically safe Class I, Zone 0 (Ex ia IIC T5...T1 Ga) networks, route the loop through approved zener barriers or galvanic isolation modules. For Zone 2 (Ex nA/Ex ec) installations, ensure the armored lines are secured against accidental displacement.

Engineering Advantages

Low-Profile Low-Clearance Retrofits

The combination of a non-threaded smooth 1.5-inch profile and a 90-degree side-exit cable make this probe ideal for older retrofits. It fits easily inside specialized brackets where standard rear-exit probes are too long, allowing users to upgrade legacy 7200 systems without machining deeper inspection caps.

Heavy-Duty Armor for Harsh Environments

The flexible stainless steel outer armor provides superior physical protection. It prevents lines from snapping or crimping when routed through exposed machine areas that are subject to routine plant maintenance, flying debris, or heavy fluid turbulence.

Global Maritime and Quality Alignment

Certified under the ABS (American Bureau of Shipping) Steel Vessels Rules and fully compliant with EMC Directive 2014/30/EU, this proximity sensor is built for marine propulsion shafts and offshore platforms. It provides reliable operation in high-vibration settings and salt-heavy environments.

Technical FAQs

Q1: How do I properly secure this smooth-case probe without case threads?
A1: A smooth case probe must be installed inside a dedicated split-clamp block or compression flange designed for 1.5-inch diameter cylinders. The clamp must distribute pressure evenly across the 64 mm stainless steel body to hold the sensor steady under high machine vibration without warping the casing.

Q2: Can the side-exit cable transition point withstand high mechanical pulling force?
A2: The side-exit housing provides strong structural protection, and the stainless steel armor is anchored firmly to the case body. However, sharp tugs or excess stress at the 90-degree bend should be avoided during installation to prevent damage to the internal triaxial shields.

Q3: What are the target ambient temperature boundaries for this sensor under EPL Ga rules?
A3: According to Bently Nevada's certified temperature schedule, the allowed ambient window depends on your target classification. It ranges from a wide -55 °C to +232 °C for a T1 rating down to a tight -55 °C to +40 °C threshold for strict T5 applications.