Bently Nevada 21501-00-12-10-02 Eddy Current Proximity Probe Product Specification
21501-00-12-10-02 is factory pre-calibrated front-mounted 5 mm eddy current proximity probe designed exclusively for Bently Nevada 7200 series transducer system. Matched with original 2155/00 proximitor preamplifier and factory-calibrated 75-ohm matched extension cable, the complete assembly forms a full non-contact measurement system compliant with API 670 industry standards for critical rotating machinery protection. Based on eddy-current induction principle, the probe converts minor clearance variations between its sensing tip and conductive metallic rotor target into linear analog voltage signals. These analog signals are transmitted to 7200 or 3500 rack-mounted monitoring modules to realize continuous online measurement of shaft radial vibration, short-stroke axial displacement and Keyphasor rotational pickup pulse signals. This model is widely equipped on compact high-speed gas turbines, miniature centrifugal compressors and small turbo-generators used in power, petrochemical and metallurgical fields, delivering over-limit alarm trigger and emergency shutdown interlock signals to ensure safe unit operation. Every finished probe is subjected to full-range linearity calibration, high-low temperature cyclic aging test and full hermetic epoxy encapsulation inspection prior to factory shipment to sustain stable measuring accuracy under harsh field conditions including high bearing housing temperature, persistent lubricating oil mist and complex electromagnetic interference from high-current power cables and variable frequency drive equipment.
Description
Bently Nevada 21501-00-12-10-02 Eddy Current Proximity Probe Product Specification
1. Product Overview
21501-00-12-10-02 is factory pre-calibrated front-mounted 5 mm eddy current proximity probe designed exclusively for Bently Nevada 7200 series transducer system. Matched with original 2155/00 proximitor preamplifier and factory-calibrated 75-ohm matched extension cable, the complete assembly forms a full non-contact measurement system compliant with API 670 industry standards for critical rotating machinery protection. Based on eddy-current induction principle, the probe converts minor clearance variations between its sensing tip and conductive metallic rotor target into linear analog voltage signals. These analog signals are transmitted to 7200 or 3500 rack-mounted monitoring modules to realize continuous online measurement of shaft radial vibration, short-stroke axial displacement and Keyphasor rotational pickup pulse signals. This model is widely equipped on compact high-speed gas turbines, miniature centrifugal compressors and small turbo-generators used in power, petrochemical and metallurgical fields, delivering over-limit alarm trigger and emergency shutdown interlock signals to ensure safe unit operation. Every finished probe is subjected to full-range linearity calibration, high-low temperature cyclic aging test and full hermetic epoxy encapsulation inspection prior to factory shipment to sustain stable measuring accuracy under harsh field conditions including high bearing housing temperature, persistent lubricating oil mist and complex electromagnetic interference from high-current power cables and variable frequency drive equipment.
2. Part Number Definition Breakdown
All coding segments follow Bently’s unified part coding specification for 7200-series front-install proximity probes. Base code 21501 represents core series of standard 5-millimeter diameter front full-thread proximity probe tailored for the 7200 transducer platform; segment 00 stands for zero exposed unthreaded tip length, fixed internal coil winding structure and factory-locked original electrical calibration parameters without customized electrical modification; segment 12 refers to ultra-short full-threaded body dimension optimized for ultra-shallow mounting holes on thin-wall standard bearing pedestals; segment 10 defines factory pre-molded integral coaxial cable with fixed 1.0-meter length permanently bonded to 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. Random replacement with non-identical part number probes changes mechanical dimensions or calibrated electrical characteristics, invalidates full-loop factory matching calibration and results in measurement deviation or unexpected protective tripping of corresponding monitoring channel.
3. Core Functional Characteristics
The probe threaded housing and sensing tip are precision machined from high-strength corrosion-resistant stainless steel with outstanding resistance against lubricant erosion and corrosive vapor accumulated inside sealed bearing cavities. Internal induction coil is fully potted with high-temperature resistant epoxy resin to eliminate internal air gaps, effectively preventing coil displacement and inter-turn short-circuit faults caused by long-term equipment running vibration and fluctuating ambient temperature. Attached 1.0-meter integral coaxial cable adopts standard 75-ohm controlled-impedance coaxial structure with dense tinned copper braided shielding over 95% coverage to restrain external electromagnetic crosstalk during field signal transmission. On-site cutting, splicing and arbitrary replacement of original cable and tail connector are strictly prohibited, all manual physical alterations permanently void factory preset full-set calibration data of the whole transducer system. Ultra-short full-thread front mounting design is exclusively optimized for ultra-shallow pre-drilled holes and thin-wall bearing pedestal structures where longer threaded probes cannot be installed properly. Built-in open-circuit and short-circuit fault diagnosis rapidly identifies abnormal wiring via obvious output voltage offset to simplify daily field troubleshooting work. Consistent linear measurement performance of the whole system can only be maintained by genuine original matching of this probe, calibrated extension cable and designated 2155/00 proximitor preamplifier.
4. Electrical and Metrological Specifications
Matching 2155/00 proximitor provides regulated negative DC working voltage ranging from -17.5VDC to -26VDC, and -24VDC is the standard nominal operating voltage for field application. Factory fixed calibrated sensitivity is 7.87 V/mm (200 mV/mil) calibrated against standard AISI4140 carbon steel target material, full-range linearity deviation is controlled within ±5% complying with API 670 specification requirement. Valid linear measuring range covers 0 mm ~ 1.27 mm to satisfy routine radial vibration and short-travel axial clearance detection of small-diameter high-speed industrial rotating shafts. Effective frequency response spans DC up to 10 kHz to synchronously collect low-frequency static thermal expansion drift and high-frequency dynamic shaft vibration signals. Recommended pre-installation gap is set near midpoint of linear range to keep stable bias working point for long-term uninterrupted equipment operation.
5. Environmental Working Parameters
Permissible continuous 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-condensing storage environment; applicable working relative humidity ranges from 5%RH to 95%RH without dew accumulation on probe outer casing and cable outer jacket surface. The probe withstands routine industrial mechanical vibration of 10Hz~2kHz generated by adjacent running rotating equipment. Long-term continuous soaking in corrosive chemical liquid, acid mist and persistent high-temperature steam environment is forbidden to avoid outer casing corrosion and premature aging of internal insulating materials. For installation location above altitude 1000 meters, shorten periodic inspection interval appropriately.
6. Installation and Routine Maintenance Guidance
Cut off total power supply of whole monitoring loop before field installation, screw the ultra-short full-thread probe into pre-reserved ultra-shallow threaded hole of bearing pedestal or custom 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 cabling construction, separate probe signal cable routing away from high-current AC power cables and inverter output wiring to reduce cross electromagnetic coupling interference. Avoid sharp small-radius bending, excessive stretching and heavy mechanical squeezing on cable body to prevent inner conductor breakage and abnormal impedance shift. Within regular maintenance cycles, periodically inspect cable outer sheath for oil corrosion, abrasion and cracking damage, and verify locking tightness of end terminal connector. When probe failure needs field replacement, only spare part with identical full part number 21501-00-12-10-02 is permitted for direct swap. 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 loops.
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