Bently Nevada 21508‑02‑12‑05‑02 — 3300‑XL 8 mm Keyphasor Proximity Probe

Description

Bently Nevada 21508‑02‑12‑05‑02 — 3300‑XL 8 mm Keyphasor Proximity Probe

Product Overview

The 21508‑02‑12‑05‑02 is a dedicated Keyphasor eddy‑current probe within Bently Nevada 3300‑XL 8 mm transducer family. It detects once‑per‑revolution notch or keyway on rotating shafts to generate phase‑reference pulse signals. This signal provides rotational speed, phase angle and vector trigger for rotor vibration analysis, balancing and machinery protection. Compliant with API 670, it is widely implemented on turbines, compressors and other high‑speed rotating equipment.

Critical Compatibility Warning

• Designed for 3300‑XL 8 mm proximitor 330180‑xx‑00 and 8 mm Microdot extension cables 330130‑xx‑xx‑00.
• Not compatible with 11 mm(330181) or NSv(330980) series hardware.
• Total system cable length = probe integral pigtail + extension cable, must precisely match the total‑system length rating of the paired 8 mm proximitor. Keyphasor pulse output feeds to 3500/42M, 3300 monitor racks for speed, phase measurement and orbit analysis.

Part Number Decoding

• 21508: 3300‑XL 8 mm Keyphasor probe
• ‑02: Reverse‑mount thread specification (3/8‑24 UNF)
• ‑12: Unthreaded body length =12 mm
• ‑05: Integral pigtail cable length =0.5 m
• ‑02: 12‑pin Microdot coaxial connector

21508-02-12-05-02

Key Specifications

Main Features

• Purpose‑built Keyphasor reverse‑mount probe: Specialized for once‑per‑revolution phase reference and shaft speed measurement, supports orbit plot, polar plot and rotor balancing analysis.
• 3/8‑24 UNF reverse‑mount thread, 12 mm unthreaded body: Fits standard rear‑access installation bores on turbomachinery casings.
• 0.5 m short integral pigtail: Requires matched 330130 extension cable to achieve required total system length.
• Standard 2.0 mm linear range: Same transducer performance as regular 3300‑XL 8 mm proximity probes.
• Broad working temperature range ‑35 °C ~ +175 °C: Tolerates oil‑mist and high casing temperature environment.
• Stainless‑steel rugged construction: High vibration resistance for continuous 24‑hour heavy‑duty service.
• 12‑pin Microdot interface: Interoperable with standard 3300‑XL 8 mm extension cables and proximitors.
• Intrinsic‑safety certified: Suitable for hazardous classified zones when installed inside complete certified 8 mm proximity loop.

Typical Application Scenarios

• Steam / gas turbine phase reference, rotational speed monitoring and rotor dynamic analysis
• Refinery & petrochemical centrifugal compressors requiring Keyphasor trigger for vibration vector calculation
• Critical large pumps, blowers and gearboxes for shaft speed and phase‑angle acquisition
• Machinery condition monitoring for orbit, polar plot and field balancing work
• Off‑shore platform rotating‑equipment protection systems
• Reverse‑mount installation scenarios where only rear‑side casing access is available
• Hazardous classified locations complying with ATEX / IECEx / CSA requirements
• Spare‑part replacement for existing reverse‑mount Keyphasor measurement loops

Related & Recommended Alternative Models

Compatible Components & Accessories

1. 8 mm extension cables: 330130‑xx‑xx‑00 Microdot extension cables. Total system length = probe 0.5 m + extension cable = proximitor rated total length.
2. Matched 8 mm proximitor: 330180‑xx‑00 DIN‑rail proximitor sensor.
3. Monitor hardware: Bently 3500/42M, 3300/12, 3300/15 monitor racks with Keyphasor input function.
4. Mounting parts: 3/8‑24 UNF lock‑nut for reverse‑mount probe securing.
5. Calibration test fixture: 8 mm static gap calibration rig for pre‑commission validation.
6. Torque wrench: For specified Microdot connector assembly torque.

Installation and Configuration Guide

Warning: Installation must be performed by qualified instrumentation technicians. Always refer to original Bently Nevada 3300‑XL official manual as primary reference document.

1. Mechanical Reverse‑Mount Installation & Target Preparation
   • Insert probe from casing rear side through 3/8‑24 UNF bore hole, fasten lock‑nut on outer threaded section.
   • Probe tip must stay perpendicular to shaft surface. Follow OEM drawing for notch / keyway depth, width and edge sharpness; poor target geometry causes distorted Keyphasor pulses.
   • Maintain safe clearance to eliminate rotor‑to‑probe collision risk across full shaft thermal‑growth and vibration excursion.
2. System‑Length Verification
   • Probe integral pigtail =0.5 m. Select extension cable so overall cable length strictly matches proximitor rated total‑system length.
   • Apply manufacturer‑recommended torque for Microdot connection. Power must be removed before connecting / disconnecting transducer loop.
3. Signal Cable Routing Requirements
   • Separate Keyphasor coaxial cable from high‑power AC, contactor and VFD wiring to reduce EMI noise and pulse distortion.
   • Respect minimum coaxial‑cable bending radius; avoid sharp bends that damage internal conductors.
4. Commissioning Gap Adjustment
   • Loosen lock‑nut, adjust probe penetration to set mechanical gap with shaft target.
   • Power up proximitor, measure DC gap‑voltage with high‑impedance multimeter. Set working point near mid‑range (approx.‑10 VDC for AISI‑4140 steel).
   • Tighten lock‑nut firmly, re‑confirm gap‑voltage remains within linear zone (‑1 VDC ~ ‑17 VDC). Rotate shaft manually and verify clean Keyphasor pulse output waveform.
5. Monitor Channel Configuration
   • Assign this channel as Keyphasor input inside monitor configuration software. Set scale factor to 7.87 V/mm (200 mV/mil) for 8 mm 3300‑XL system.
   • Configure trigger threshold, speed range and fault parameters per machine OEM specifications.
   • Execute loop fault test to confirm Not‑OK diagnostic function responds to probe open‑circuit condition.
6. Maintenance & Troubleshooting
   • Inspect Microdot connector for dirt, corrosion and loose contact during machinery turnaround.
   • Check Keyphasor pulse waveform quality; noisy or missing pulse usually relates to target notch wear, gap drift, connector degradation or cable damage.
   • Not‑OK fault: inspect probe tip, cable integrity and connector. Probe cannot be repaired on‑site; replace complete probe assembly upon hardware failure.
7. Hazardous‑Area Installation Notes
   • For ATEX / IECEx classified‑zone deployment, strictly implement 3300‑XL intrinsic‑safety rules for power supply, cable specification, shielding and chassis grounding.

Supplementary Remark

21508‑02‑12‑05‑02 is reverse‑mount 3300‑XL 8 mm Keyphasor probe with 3/8‑24 UNF thread, 12 mm unthreaded body, 0.5 m integral pigtail and 12‑pin Microdot connector. It provides once‑per‑revolution phase‑reference pulse for speed, phase and rotor dynamic analysis. It shall only pair with standard 8 mm series proximitor and extension cables. Prior to commissioning, validate part‑number configuration, reverse‑mount thread dimension, pigtail length, connector type, target notch geometry and total‑system cable length against project BOM and mechanical drawings.