Bently Nevada 21505-00-60-10-02 Eddy Current Proximity Probe Product Specification
21505-00-60-10-02 is factory pre-calibrated standard front-mounted 5 mm eddy current proximity probe for Bently Nevada 7200 series transducer system. Paired with model 2155/00 proximitor and matched 75-ohm calibrated extension cable, it forms a complete non-contact measurement system compliant with API 670 rotating machinery protection standards. Following eddy-current induction principle, the probe converts clearance fluctuation between sensing tip and conductive metallic rotor target into linear analog voltage signals, which are transmitted to 7200 or 3500 rack monitor modules to realize continuous measurement of shaft radial vibration, short-stroke axial displacement and Keyphasor pickup signal. Widely equipped on steam turbines, gas turbines, centrifugal compressors and large turbo-generators across power, petrochemical and metallurgical industries for alarm triggering and emergency shutdown interlock control. Every finished probe passes linearity calibration, high-low temperature cyclic aging test and hermetic encapsulation inspection before factory shipment to retain stable measuring accuracy under harsh on-site conditions of high bearing housing temperature, lubricant oil mist and complicated electromagnetic interference from high-power drives and power cables.
Description
Bently Nevada 21505-00-60-10-02 Eddy Current Proximity Probe Product Specification
1. Product Overview
21505-00-60-10-02 is factory pre-calibrated standard front-mounted 5 mm eddy current proximity probe for Bently Nevada 7200 series transducer system. Paired with model 2155/00 proximitor and matched 75-ohm calibrated extension cable, it forms a complete non-contact measurement system compliant with API 670 rotating machinery protection standards. Following eddy-current induction principle, the probe converts clearance fluctuation between sensing tip and conductive metallic rotor target into linear analog voltage signals, which are transmitted to 7200 or 3500 rack monitor modules to realize continuous measurement of shaft radial vibration, short-stroke axial displacement and Keyphasor pickup signal. Widely equipped on steam turbines, gas turbines, centrifugal compressors and large turbo-generators across power, petrochemical and metallurgical industries for alarm triggering and emergency shutdown interlock control. Every finished probe passes linearity calibration, high-low temperature cyclic aging test and hermetic encapsulation inspection before factory shipment to retain stable measuring accuracy under harsh on-site conditions of high bearing housing temperature, lubricant oil mist and complicated electromagnetic interference from high-power drives and power cables.
2. Part Number Definition Breakdown
Each segmented code complies with Bently’s dedicated 7200-series proximity probe coding specification. Base code 21505 represents core product series of standard front-install 5 mm proximity probe for 7200 transducer platform; segment 00 defines fixed internal coil winding layout, body structural parameters and factory-locked original calibration setting; segment 60 specifies extra-long customized threaded body dimension for deep-hole installation requirement; segment 10 stands for factory pre-molded integral cable fixed length of 1.0 meter permanently connected with probe body; final segment 02 denotes miniature coaxial terminal connector at cable end for docking with original matching extension cable. Any probe with different segment digits owns varied mechanical size or calibrated electrical data and cannot be replaced arbitrarily on-site, as improper substitution invalidates full-loop factory calibration and leads to measurement drift or accidental equipment protection trip.
3. Core Functional Characteristics
The probe threaded body and sensing head are made of high-strength anti-corrosion stainless steel, featuring outstanding oil and vapor resistance to adapt long-term operation inside closed bearing housings filled with lube oil vapor. Internal induction coil is fully potted with high-temperature epoxy resin to eliminate inner air gaps, effectively avoiding coil displacement and inter-turn short-circuit caused by long-running equipment vibration and ambient temperature variation. The attached 1-meter integral cable adopts standard 75-ohm controlled-impedance coaxial construction with dense tinned copper braided shielding above 95% coverage to suppress external electromagnetic crosstalk during signal transmission. Field cutting, splicing or connector replacement on original integral cable is strictly forbidden; any physical modification permanently voids factory preset calibration parameters. Only full set matching of original probe, designated extension cable and 2155/00 proximitor keeps consistent linear conversion characteristic of the whole measuring system, and open/short-circuit wiring faults can be rapidly judged via obvious output voltage offset to simplify daily field troubleshooting.
4. Electrical and Metrological Specifications
The supporting 2155/00 proximitor provides regulated negative DC power ranging from -17.5 VDC to -26 VDC, with standard field operating voltage at -24 VDC. Factory fixed calibrated sensitivity is 7.87 V/mm (200 mV/mil) based on standard AISI4140 carbon steel target, full-range linearity tolerance is controlled within ±5% in accordance with API 670 specification. Valid linear measuring range is 0 mm ~ 1.27 mm for small-gap radial vibration and short-travel axial clearance monitoring of industrial rotating shafts. Effective frequency response covers DC up to 10 kHz to capture both slow static thermal expansion drift and high-frequency dynamic shaft vibration signals. Recommended pre-installation gap is set near the midpoint of linear range to maintain stable bias working point for continuous long-term operation.
5. Environmental Working Parameters
Continuous permissible operating temperature of probe sensing part ranges from -35°C to +120°C for installation near high-temperature bearing pedestals and turbine casings. Spare storage temperature is kept between -55°C and +85°C under dry non-condensing storage environment; applicable working relative humidity spans 5%RH ~ 95%RH without dew accumulating on probe shell and cable outer jacket. The probe withstands regular industrial vibration of 10 Hz ~ 2 kHz generated by adjacent running rotating equipment. Long-term continuous immersion in corrosive liquid, acid mist and persistent high-temperature steam is prohibited to prevent shell corrosion and inner insulation aging damage. For installation sites above 1000 meters altitude, shorten periodic inspection cycle appropriately.
6. Installation and Routine Maintenance Guidance
Cut off power supply of entire monitoring loop before installation, screw the long-thread probe into deep reserved threaded hole of bearing housing or custom mounting fixture, adjust pre-set installation gap to rated design value and lock fastening nut to prevent loosening induced by long-term unit vibration. During cabling construction, separate probe signal cable routing away from high-current AC power lines and inverter output wiring to reduce cross electromagnetic coupling interference. Avoid sharp small-radius bending, overstretching and heavy extrusion on cable body to prevent inner core breakage and impedance deviation. Within regular maintenance period, periodically inspect cable outer sheath for oil corrosion, abrasion and crack damage, and check locking tightness of end connector. When probe fails and needs replacement, only spare part with identical full part number 21505-00-60-10-02 is allowed for direct swap. All replacement probes complete full electrical performance test and alternating temperature aging screening before factory outbound delivery to guarantee full interchangeability inside original vibration monitoring loops.
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