Bently Nevada 27482-08-12-18-72 Radiation Resistant Proximity Probe

Product Overview

The Bently Nevada 27482-08-12-18-72 is a specialized Radiation Resistant Proximity Probe built for high-radiation industrial environments. Engineers deploy this 27482 Series transducer in nuclear power plants and harsh turbine monitoring systems. It measures static and dynamic shaft positions without physical contact. The unit features a rugged 0.300-inch probe tip and stainless steel armor. This construction protects the internal coil from mechanical abrasion and intense ionizing radiation. Manufactured in the U.S.A., the probe maintains signal integrity where standard eddy current sensors fail.

Part Number Configuration Breakdown

• Base Series (27482): 0.300-inch tip diameter, 3/8-24 UNF thread, 5/16-inch wrench flats, with flexible stainless steel armor.
• Unthreaded Length Option (08): 80 mm (3.15 inches) unthreaded section behind the probe tip.
• Overall Case Length Option (12): 1.2 inches total threaded case length.
• Total Electrical Length Option (18): 18 inches total electrical cable length (matched for 36448 and 27482 probes).
• Armor / Extended Option (72): 72 inches (1.82 meters) armored assembly specification.

Technical Specifications

Installation Guidelines

• Target Preparation: Machine the target shaft surface to AISI 4140 steel standards without chrome plating.
• Mechanical Mounting: Thread the 3/8-24 UNF case into a rigid bracket using a 5/16-inch open-end wrench.
• Gap Setting: Set the initial mechanical gap to 1.27 mm (50 mils), targeting approximately -9.0 VDC output.
• Cable Routing: Secure the 72-inch armored cable with P-clips to prevent flow-induced vibration fatigue.
• Side Clearance: Maintain at least 1.5 tip diameters of clearance around the 0.300-inch tip to avoid side-wall interference.

Commissioning & Maintenance Convenience

• Fast Verification: Technicians verify probe health using a simple digital multimeter to check coil resistance.
• Zero Calibration Drift: High-temperature radiation-tolerant polymers prevent tip swelling and zero-point drift over long outages.
• Modular Replacement: Miniature coaxial connectors allow rapid disconnect during scheduled nuclear refueling outages.

System Compatibility

• Extension Cables: Pairs exclusively with Bently Nevada radiation-resistant coaxial extension cables matching the 18-inch electrical length system.
• Proximitor Sensors: Compatible with matching Bently Nevada 3300 / 7200 Series radiation-rated Proximitor oscillators.
• Monitoring Racks: Interfaces directly with Bently Nevada 3500 and 3300 Machinery Protection Systems.

Certifications & Compliance

• Quality Management: Manufactured under ISO 9001 certified quality systems in the U.S.A.
• Nuclear Qualification: Engineered to meet stringent nuclear power plant radiation exposure standards (IEEE 323 guidelines).
• Industry Standards: Complies with API 670 mechanical vibration and axial position measurement requirements.

Packing List

• 1 × Bently Nevada 27482-08-12-18-72 Radiation Resistant Proximity Probe
• 1 × Protective Tip Cap and Connector Dust Boot
• 1 × Factory Calibration and Quality Inspection Sheet

Selection Guide

• Verify Thread Size: Confirm your bearing housing bracket accepts a 3/8-24 UNF thread before ordering.
• Check Case Geometry: Ensure the 80 mm unthreaded length and 1.2-inch case length clear thick machine walls.
• Match System Electrical Length: Always match the 18-inch electrical length with the correct extension cable and Proximitor.
• Evaluate Radiation Dose: Select the 27482 Series over standard 3300 XL probes whenever cumulative gamma exposure exceeds 10⁶ rads.

Frequently Asked Questions (FAQ)

Q1: What differentiates the 27482 Series from standard 3300 XL proximity probes?

A1: Standard probes suffer polymer degradation under ionizing radiation. The 27482 Series uses specialized radiation-hardened plastics and insulation to survive nuclear containment zones.

Q2: Can I shorten or splice the 18-inch coaxial cable on the 27482-08-12-18-72?

A2: Never cut or splice the probe cable. Changing the physical cable length alters capacitance and ruins the tuned LC resonant circuit.

Q3: How do field engineers test this probe during a plant outage?

A3: Disconnect the coaxial connector and measure resistance between the center pin and outer shield. A healthy 27482 coil reads roughly 4 to 7 ohms.

Q4: Why does the part number list both 18 inches and 72 inches?

A4: The 18 designates the calibrated electrical cable length, while 72 defines the extended 72-inch (1.82 m) armored assembly length.

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