Bently Nevada 21504-000-096-05-02 Eddy Current Proximity Probe Product Specification
21504-000-096-05-02 is factory pre-calibrated front-mounted 8 mm eddy current proximity probe specially designed for Bently Nevada 7200 series transducer system. When combined with matching original 2155/00 proximitor preamplifier and factory-calibrated 75-ohm impedance-matched extension cable, the whole set forms a complete non-contact displacement measurement system that fully complies with API 670 industry specification for critical rotating machinery protection. Based on eddy current induction working principle, the probe converts tiny clearance variation between its sensing tip and conductive metallic rotor target into continuous linear analog voltage output signals. These analog signals are transmitted to 7200 or 3500 rack-mounted monitoring modules to perform continuous online measurement of shaft radial vibration, short-travel axial displacement and Keyphasor rotational trigger pulse signals. This probe is widely installed on steam turbines, gas turbines, centrifugal compressors and large generator units within power generation, petrochemical and metallurgical industries to provide over-limit alarm output and emergency shutdown interlock signal for safe unit operation. Every finished probe is subject to strict full-range linear calibration, high-low temperature cyclic aging test and full epoxy hermetic encapsulation inspection before factory delivery to ensure stable and consistent measuring accuracy under severe field operating conditions including high ambient temperature inside bearing housings, pervasive lubricating oil mist and complicated electromagnetic interference generated by high-current power cables and variable frequency drive equipment.
Description
Bently Nevada 21504-000-096-05-02 Eddy Current Proximity Probe Product Specification
1. Product Overview
21504-000-096-05-02 is factory pre-calibrated front-mounted 8 mm eddy current proximity probe specially designed for Bently Nevada 7200 series transducer system. When combined with matching original 2155/00 proximitor preamplifier and factory-calibrated 75-ohm impedance-matched extension cable, the whole set forms a complete non-contact displacement measurement system that fully complies with API 670 industry specification for critical rotating machinery protection. Based on eddy current induction working principle, the probe converts tiny clearance variation between its sensing tip and conductive metallic rotor target into continuous linear analog voltage output signals. These analog signals are transmitted to 7200 or 3500 rack-mounted monitoring modules to perform continuous online measurement of shaft radial vibration, short-travel axial displacement and Keyphasor rotational trigger pulse signals. This probe is widely installed on steam turbines, gas turbines, centrifugal compressors and large generator units within power generation, petrochemical and metallurgical industries to provide over-limit alarm output and emergency shutdown interlock signal for safe unit operation. Every finished probe is subject to strict full-range linear calibration, high-low temperature cyclic aging test and full epoxy hermetic encapsulation inspection before factory delivery to ensure stable and consistent measuring accuracy under severe field operating conditions including high ambient temperature inside bearing housings, pervasive lubricating oil mist and complicated electromagnetic interference generated by high-current power cables and variable frequency drive equipment.
2. Part Number Definition Breakdown
All coding segments follow unified Bently Nevada part coding specification for 7200 series front-installed proximity probes. Base code 21504 represents core product series of standard 8-millimeter diameter front-thread proximity probe exclusively developed for the 7200 transducer platform; segment 000 stands for zero exposed unthreaded tip length and fixed standard internal coil winding structure with factory locked original electrical calibration parameters without special customized electrical modification; segment 096 refers to ultra-long full-threaded body dimension customized for deep embedded installation on extra-thick bearing pedestals and deep installation hole layout; segment 05 defines factory integrated fixed integral coaxial cable length of 0.5 meter permanently molded together with probe main body during original production; final suffix code 02 indicates standard miniature male coaxial terminal connector pre-mounted at cable tail for plug-type connection with original calibrated matched extension cable. Any alteration of digital coding will change probe mechanical dimension or factory preset electrical calibration parameter, random on-site replacement with non-same part number product will damage full-loop matching calibration and cause measuring deviation or unexpected protection trip of corresponding monitoring channel.
3. Core Functional Characteristics
The probe threaded housing and sensing head are precision machined from high-density anti-corrosion stainless steel material with excellent erosion resistance against bearing lubricant oil and weak corrosive vapor inside sealed bearing cavity. Internal induction coil is fully filled and fixed with high-temperature resistant epoxy potting adhesive to eliminate internal air gap, effectively avoid coil displacement and inter-turn short-circuit failure caused by long-term equipment running vibration and fluctuating ambient temperature. Attached 0.5-meter integral coaxial cable adopts standard 75-ohm controlled impedance structure with over 95% coverage dense tinned copper braided shielding layer to effectively restrain external electromagnetic crosstalk during on-site long-distance signal transmission. Field cutting, joint splicing and arbitrary replacement of original cable and tail connector are strictly prohibited, all manual physical changes will permanently invalidate factory preset full-set calibration data of the whole transducer system. Ultra-long full-thread customized body design is exclusively optimized for ultra-deep buried installation environment of special thick-wall bearing seat structure. Built-in open-circuit and short-circuit self-diagnosis function rapidly feeds back abnormal wiring state through obvious output voltage offset to simplify daily field circuit troubleshooting work. Complete measuring linearity of the whole system can only be maintained by original matching of this probe, designated calibrated extension cable and supporting 2155/00 proximitor preamplifier.
4. Electrical and Metrological Specifications
Matched supporting 2155/00 proximitor supplies regulated negative DC working voltage ranging from -17.5VDC to -26VDC, and -24VDC is the standard rated operating voltage adopted in practical industrial field. Factory fixed calibrated sensitivity is 7.87V/mm (200mV/mil) with standard AISI4140 carbon steel as calibration target material, full measuring range linearity error is controlled within ±5% complying with API670 specification requirement. Valid linear measuring range covers 0mm~2.0mm, which satisfies routine radial vibration and short-stroke axial clearance detection of most large industrial rotating shafts. Effective frequency response range covers DC to 10kHz, synchronously collecting low-frequency static thermal expansion drift signal and high-frequency dynamic shaft vibration signal. Recommended pre-installation gap is set at middle position of linear measuring range to ensure stable bias working point for long-time uninterrupted equipment operation.
5. Environmental Working Parameters
Continuous allowable operating temperature of probe sensing part ranges from -35°C to +120°C to adapt high-temperature installation surroundings near heated bearing housings and turbine cylinder casings. Spare part storage temperature is controlled between -55°C and +85°C under dry non-condensation storage environment; applicable working relative humidity ranges from 5%RH to 95%RH without dew accumulation on probe outer casing and cable outer sheath surface. The probe can withstand routine mechanical vibration of 10Hz~2kHz generated by adjacent operating rotating equipment. Long-term continuous soaking in corrosive chemical liquid, acid mist and persistent high-temperature steam environment is forbidden to prevent outer shell corrosion and internal insulating layer aging damage. For installation location above altitude 1000 meters, shorten regular equipment inspection cycle properly.
6. Installation and Routine Maintenance Guidance
Cut off total power supply of whole monitoring loop before field installation, screw the customized ultra-long full-thread probe into pre-reserved deep threaded hole of bearing pedestal or special customized mounting fixture, adjust pre-set installation clearance to rated design value and lock fastening nut tightly to prevent installation looseness induced by long-term equipment running vibration. During field wiring construction, separate probe signal cable routing away from high-current AC power cable and inverter output wiring to reduce cross electromagnetic coupling interference. Avoid sharp small-radius bending, excessive stretching and heavy mechanical extrusion on cable body to prevent inner conductor breakage and impedance abnormal drift. Within regular equipment maintenance cycle, periodically check cable outer jacket for oil corrosion, abrasion and cracking damage, and inspect locking tightness of tail terminal connector. When probe performance failure needs field replacement, only spare part with identical full part number 21504-000-096-05-02 can be directly replaced. All replacement probes complete full electrical performance testing and alternating temperature aging screening before factory outbound delivery to guarantee full interchangeability inside original vibration monitoring measuring loop.
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