Description
Bently Nevada 74712‑01‑10‑02‑00
3300‑XL 8 mm Keyphasor Eddy‑Current Probe Assembly (Standard‑Temperature, Non‑Hazardous‑Area)
Product Overview
The 74712‑01‑10‑02‑00 is a dedicated Keyphasor eddy‑current proximity probe from Bently Nevada 3300‑XL 8 mm Microdot transducer family. It is purpose‑built to detect shaft keyways or machined notches, generating a once‑per‑revolution trigger pulse. This probe delivers reference signals for rotational speed measurement, vibration phase analysis, rotor dynamic balancing and machinery sequence monitoring on turbomachinery. It meets API‑670 protection requirements for rotating equipment. Suffix ‑00 indicates no hazardous‑area certifications, intended for general‑purpose non‑explosive industrial locations.
Critical Compatibility Warning
- This is legacy Microdot‑interface Keyphasor probe. Compatible exclusively with 3300‑XL standard‑temperature Microdot extension cables (330130 series). Not compatible with NSv ClickLoc (330930 series) or ETR‑rated 330190 high‑temperature cables.
- Total calibrated transducer loop length = probe integral pigtail length + matched standard‑grade Microdot extension‑cable length. The summed length must match the configured length parameter of the paired Microdot‑type proximitor. Length mismatch will cause pulse distortion, speed jitter and inaccurate phase readings.
- Termination: straight Microdot 10‑32 coaxial connector. Do not cut, splice or modify factory‑molded integral pigtail assembly. This unit shall not be installed in explosive classified hazardous zones.
Part Number Decoding
- 74712：Base model, 3300‑XL 8 mm dedicated Keyphasor proximity probe
- ‑01：Mounting thread specification: 3/8‑24 UNF
- ‑10：Probe housing overall length: 100 mm
- ‑02：Integral non‑armored pigtail cable length: 2.0 meters
- ‑00：Certification option: No ATEX / IECEx / CSA hazardous‑area intrinsic‑safety approvals
74712-01-10-02-00
Key Specifications
| Parameter | Value |
|---|---|
| Part Number | 74712‑01‑10‑02‑00 |
| Series | 3300‑XL 8 mm Microdot Keyphasor Probe Transducer |
| Measurement Principle | Non‑contact eddy‑current displacement for phase‑mark triggering |
| Nominal Sensitivity | 7.87 V/mm (200 mV/mil), ±5 % tolerance |
| Linear Measurement Range | 0.25 mm ~ 2.0 mm (10‑80 mil) |
| Probe Tip Diameter | 8 mm |
| Mounting Thread | 3/8‑24 UNF |
| Housing Overall Length | 100 mm |
| Integral Pigtail | 2.0 m, non‑armored standard‑grade FEP insulation |
| Connector Type | Straight Microdot 10‑32 coaxial |
| Frequency Response | 0 Hz‑10 kHz |
| Operating Temperature Range | ‑52 °C ~ +121 °C (standard temperature rating) |
| Housing Material | 316 stainless steel |
| Certifications | API‑670 compliant; No hazardous‑area intrinsic‑safety approvals |
| Country of Origin | USA |
| Weight | ≈0.24 kg |
Main Features
- Specialized Keyphasor trigger performance: Optimized for shaft keyway / notch detection to generate reliable once‑per‑revolution reference pulse, supporting tachometer speed reading, vibration‑phase calculation and rotor balancing work flows.
- 100 mm housing with 3/8‑24 UNF mounting thread: Widely adopted mechanical thread form for phase‑reference mounting points on turbine and compressor bearing housings.
- 2.0 m factory‑calibrated standard‑temperature non‑armored integral pigtail with straight Microdot connector: Works together with 330130‑series standard‑grade tri‑axial extension cables to achieve required total transducer‑loop length.
- Standard temperature rating: Suitable for general‑purpose plant ambient conditions; not applicable for continuous high radiant‑heat locations requiring ETR‑qualified components.
- Robust industrial construction: Resists oil‑mist, humidity and machinery vibration, fulfils API‑670 phase‑reference requirements for critical rotating assets.
- Full interoperability within legacy 3300‑XL standard‑temperature Microdot transducer ecosystem.
Typical Application Scenarios
- Once‑per‑revolution phase‑mark detection for steam turbines, gas turbines and centrifugal compressors in non‑hazardous industrial areas
- Rotational speed monitoring, vibration‑phase angle measurement and rotor balancing reference for fluid‑film‑bearing rotating machinery
- Conventional power‑plant machinery‑house installations without explosive‑zone classification
- System integration with Bently Nevada 3500 rack Microdot‑compatible Keyphasor proximitor input channels
- Spare‑part replacement for existing standard‑temperature Microdot Keyphasor measurement loops
Related & Recommended Alternative Models
| Model | Description |
|---|---|
| 74712‑01‑10‑02‑05 | 2.0 m pigtail Keyphasor probe, multi‑hazardous‑area intrinsic‑safety approvals |
| 74712‑01‑10‑10‑00 | 1.0 m integral pigtail Keyphasor probe, non‑hazardous‑area version |
| 74712‑03‑10‑02‑00 | 2.0 m Keyphasor probe, 1/4‑28 UNF thread, non‑hazardous‑area |
| 330130‑075‑00‑05 | 7.5 m non‑armored standard‑grade extension cable, dual‑end right‑angle Microdot |
| 330190‑085‑00‑05 | 8.5 m ETR high‑temperature extension cable (ETR only, not interchangeable) |
Compatible Components & Accessories
- Extension Cables: 330130 series standard‑temperature Microdot tri‑axial extension cables (straight / right‑angle variants)
- Monitoring Hardware: Standard‑temperature Microdot‑type proximitor modules, Bently Nevada 3500 rack Keyphasor‑enabled Microdot monitor channels
- Mechanical Accessories: Probe mounting lock‑nut, probe mounting shell assembly, 43501‑02‑04‑02 low‑pressure cable‑seal assembly, 43574‑04 multi‑hole grommet
- Installation Consumables: Anti‑seize compound for mounting threads, cable clamps for strain‑relief, high‑temperature cable ties
- Tooling: Specified‑torque Microdot connector tightening tool
- Calibration Tool: 8 mm 3300‑XL Microdot static gap calibration fixture
Installation and Configuration Guide
Warning: Installation shall be performed by qualified instrument technicians. Always reference the original Bently Nevada 3300‑XL Microdot transducer‑system manual as primary technical source. This model has no hazardous‑area certifications and must not be installed in explosive classified zones.
- Pre‑installation Total‑Length Calculation
- Calculate total transducer loop length = probe integral pigtail (2.0 m) + selected standard‑grade Microdot extension‑cable length.
- Confirm total length strictly matches calibrated‑length requirement of paired Microdot proximitor. Length mismatch results in distorted Keyphasor pulse and incorrect speed / phase data.
- Keyphasor Mechanical Mounting
- Install matching probe mounting shell onto bearing housing.
- Apply anti‑seize compound to 3/8‑24 UNF probe thread. Screw probe into mounting shell, adjust working gap for optimal trigger performance against shaft notch / keyway geometry, fasten lock‑nut to specified torque.
- Confirm probe tip maintains safe clearance and will not contact rotating‑shaft surface across full operating speed range. Verify valid trigger pulse output by observing gap‑voltage variation.
- Cable Routing & Microdot Connector Mating
- Route tri‑axial transducer cable separately from high‑power AC, VFD and contactor wiring to reduce EMI‑induced signal noise.
- Maintain minimum static bending radius ≥50 mm; avoid sharp kinks. Never pull cable assembly by Microdot connector housing.
- Clean Microdot contact pins; align keyway and tighten to manufacturer‑specified torque value. Do not over‑torque connector assembly.
- Install strain‑relief clamps adjacent to connector joint. Where cable penetrates machine casing, fit approved cable‑seal fitting.
- System Commissioning
- Complete full transducer‑loop assembly and power‑up proximitor / monitoring rack.
- Inspect Keyphasor pulse waveform and static gap voltage to validate mechanical gap setting. Perform static‑gap calibration test with 8 mm Microdot calibration fixture to confirm system scale‑factor.
- Clear Not‑OK fault status; configure speed alarm thresholds and phase‑monitor parameters according to project machinery specification.
- Maintenance & Troubleshooting
- During machinery turnaround, check probe locking torque, inspect Microdot connector for oil contamination and corrosion; examine pigtail outer jacket for abrasion or cracking damage.
- Missing / unstable Keyphasor pulse, signal noise or persistent Not‑OK faults may be caused by improper trigger gap, worn shaft notch, loose Microdot joint, cable damage or incorrect total transducer‑loop length.
- Replace complete factory probe assembly upon pigtail or probe‑tip damage; field‑splicing of integral probe pigtail cable is strictly prohibited.
Supplementary Remark
74712‑01‑10‑02‑00 is a dedicated 3300‑XL 8 mm Microdot Keyphasor proximity probe with 3/8‑24 UNF thread, 100 mm housing and 2.0 m standard‑temperature integral pigtail. Without hazardous‑area certifications, it is used for phase‑mark detection, rotational‑speed and vibration‑phase measurement within non‑explosive industrial environments. It only works with standard‑temperature Microdot‑system components and cannot interoperate with ETR high‑temperature cables or NSv ClickLoc hardware. Before commissioning, cross‑check Keyphasor mounting requirements, total transducer‑loop length, Microdot interface and site area classification against project BOM and mechanical drawings.
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