21504-000-032-10-02 Bently Nevada 8mm Standard Mount Proximity Probe

Product Overview

The 21504-000-032-10-02 is a cornerstone of the Bently Nevada legacy 7200 series transducer line, specifically configured as an 8mm Standard Mount Proximity Probe. This sensor serves as a high-precision, non-contact displacement transducer designed to measure radial vibration and axial position on critical rotating machinery. Whether monitoring a high-speed centrifugal compressor or a large-scale steam turbine, this probe provides the essential raw data required for the 7200 series monitoring system to detect early signs of mechanical distress.

Utilizing eddy current technology, the 21504-000-032-10-02 converts the physical gap between the probe tip and the shaft into a proportional voltage signal. Its 3/8-24 threaded body allows for direct installation into bearing housings, while the robust 8mm tip diameter ensures excellent linearity and resistance to environmental interference. Engineered for the "set-and-forget" reliability demanded by the power generation and oil and gas industries, this probe remains a trusted solution for asset protection.

Technical Configuration

The 21504-000-032-10-02 model code defines the precise mechanical dimensions required for specialized industrial mounting.

Unthreaded Length (000)

The 000 option indicates 0.0 inches of unthreaded length. The 3/8-24 threads run the entire length of the probe case to the tip, providing maximum flexibility for adjustment within mounting brackets or deep threaded holes.

Overall Case Length (032)

The 032 designation specifies a total case length of 32 mm. This compact footprint is ideal for standard bearing housings where internal clearance is sufficient, but a shorter body is preferred to minimize the cantilever effect during high-vibration events.

Total Length (10)

This probe features a 1.0-meter (39.4 inches) total length. This is the standard "pigtail" configuration, designed to connect to an extension cable. The factory tolerance allows for +0.25 meters / -0.10 meters, ensuring adequate reach to the junction box.

Connector Option (02)

The 02 configuration includes the Miniature male coaxial connector. This specialized interface is designed for low-loss signal transmission and serves as the bridge to the 7200 series extension cable and Proximitor®.

Technical Specifications

Engineering Advantages

The 21504 series is built for extreme industrial longevity:

• High-Temperature Resilience: The PPS tip and stainless steel case handle the intense thermal cycling found near turbine bearings without signal drift or material degradation.

• Hermetic Integrity: The probe is sealed to prevent oil or moisture from wicking through the cable, ensuring the coaxial dielectric remains dry and the calibration stays within factory specs.

• Legacy Reliability: As part of the 7200 series family, this probe offers a proven track record of decades-long service life in mission-critical applications where failure is not an option.

Installation & Maintenance Guide

Success with the 7200 series begins with precise gapping and secure cabling.

Setting the Gap

Connect the probe to its designated Proximitor®. Use a voltmeter to monitor the DC output. For a standard 7200 system, adjust the probe until you reach approximately -10.0 VDC (the center of the linear range). Ensure the shaft is in its normal resting position before tightening the jam nuts.

Cable Protection

Never leave the miniature coaxial connector exposed to the elements. Always use a connector protector or weather-proof junction box. If the cable must pass through oily areas, ensure the conduit is sealed to prevent "oil-soaking" the cable jacket, which can change the system capacitance over time.

Torque and Tightening

Tighten the jam nuts to a maximum of 13.6 N·m (120 in·lb). Do not over-torque, as the 3/8-24 threads on the stainless steel case can strip if handled with excessive force, potentially damaging the machine's mounting hole.

Technical FAQs

Q1: Is the 21504 probe compatible with the newer 3300 XL Proximitor?

A1: While the 21504 is part of the 7200 series, it can often be used with 3300 XL systems if the total system length and calibration match. However, for maximum accuracy and compliance, it is best paired with 7200 series components.

Q2: What is the "CN" equivalent for this model?

A2: If your site requires Chinese hazardous area approvals (NEPSI), you would typically look for a model suffix that includes "CN". The standard 21504-000-032-10-02 is the baseline North American/Global version.

Q3: Can I cut the 1.0m pigtail to a shorter length?

A3: Never cut the cable. The 1.0m length is a critical part of the tuned electrical circuit. Shortening the cable will change the system impedance, leading to massive errors in your vibration and thrust readings.

Q4: Why is the shipping weight 3 kg?

A4: To protect the precision-ground threads and the sensitive tip, Bently Nevada utilizes heavy-duty, anti-static protective packaging. The 3 kg weight ensures that the probe arrives at your facility in factory-calibrated condition.