Bently Nevada 27890-1-00-40-50-2 Eddy Current Proximity Probe Product Specification 1. Product Overview
27890-1-00-40-50-2 is an integrated armored eddy current proximity probe from Bently Nevada 3300XL standard sensor family, fully pre-calibrated at factory as an all-in-one assembly with probe body and integral armored cable molded into a single unit. Complying with API 670 turbomachinery protection specification, this probe works together with matching proximitor and calibrated 2789-series extension cable to build a complete closed-loop measurement system widely used in thermal power, petrochemical and metallurgical industries. It is designed for continuous non-contact measurement of rotor radial vibration, thrust bearing axial displacement and Keyphasor once-per-revolution pulse signal on steam turbines, turbo-generators, centrifugal compressors and large industrial blowers. Every finished probe undergoes strict linearity calibration, insulation resistance testing, alternating high-low temperature cycling aging test and anti-vibration durability inspection before factory delivery to maintain stable measuring performance under harsh working environments with high ambient temperature, heavy lubricant oil mist and complicated industrial electromagnetic interference inside bearing housings. The clearance variation between probe tip and conductive metal target surface is converted into proportional linear analog voltage signal and transmitted to 3500 or 3300 series rack monitor modules for real-time data monitoring, pre-alarm activation and critical equipment safety interlock protection.
Description
Bently Nevada 27890-1-00-40-50-2 Eddy Current Proximity Probe Product Specification
1. Product Overview
27890-1-00-40-50-2 is an integrated armored eddy current proximity probe from Bently Nevada 3300XL standard sensor family, fully pre-calibrated at factory as an all-in-one assembly with probe body and integral armored cable molded into a single unit. Complying with API 670 turbomachinery protection specification, this probe works together with matching proximitor and calibrated 2789-series extension cable to build a complete closed-loop measurement system widely used in thermal power, petrochemical and metallurgical industries. It is designed for continuous non-contact measurement of rotor radial vibration, thrust bearing axial displacement and Keyphasor once-per-revolution pulse signal on steam turbines, turbo-generators, centrifugal compressors and large industrial blowers. Every finished probe undergoes strict linearity calibration, insulation resistance testing, alternating high-low temperature cycling aging test and anti-vibration durability inspection before factory delivery to maintain stable measuring performance under harsh working environments with high ambient temperature, heavy lubricant oil mist and complicated industrial electromagnetic interference inside bearing housings. The clearance variation between probe tip and conductive metal target surface is converted into proportional linear analog voltage signal and transmitted to 3500 or 3300 series rack monitor modules for real-time data monitoring, pre-alarm activation and critical equipment safety interlock protection.
2. Part Number Segment Definition
Each segmented code of 27890-1-00-40-50-2 defines exclusive factory preset configuration parameters. The prefix code 27890 stands for integrated armored proximity probe base series with stainless steel flexible armor structure; the second digit 1 represents standard 8mm tip dimension specification with fixed factory calibrated sensitivity and corresponding linear measurement range; segment 00 means standard mechanical structure without customized modification on probe thread or encapsulation; number 40 specifies the total length of factory pre-attached integral armored cable in inches; code 50 defines the connector structure and interface specification at the cable tail end of the integrated probe; the final digit 2 stands for standard terminal connector style designed to mate seamlessly with 2789-series matched extension cables and standard Bently proximitor units. All length and electrical parameters are locked via factory calibration, and random replacement of mismatched accessories will damage the whole loop’s original calibration accuracy.
3. Core Functional Characteristics
Based on high-frequency eddy current induction working principle, the probe realizes entirely contact-free gap measurement without mechanical friction or abrasion between sensing head and rotating shaft target surface, effectively eliminating wear failure risk existing in contact-type displacement sensors. Its primary application covers real-time radial shaft vibration monitoring, thrust axial position tracking and Keyphasor signal pickup to provide phase reference for vibration spectrum analysis of rotating machinery. The integrated cable is wrapped with flexible stainless steel spiral armor layer to protect inner coaxial core against mechanical extrusion, sharp scratch and long-term oil corrosion during field installation and equipment long-period running. After matching with designated original proximitor and calibrated extension cable, the full transducer system outputs linear voltage corresponding to actual clearance value, allowing backend monitor modules to configure multi-stage warning and shutdown thresholds; once measured mechanical displacement exceeds preset safe limit, the system triggers corresponding alarm or emergency interlock to avoid catastrophic mechanical damage of critical turbomachinery. High-temperature resistant sealed encapsulation on probe head enables reliable continuous operation inside high-temperature oil-filled bearing housings.
4. Electrical and Metrological Specifications
The complete probe-cable-proximitor measurement loop is powered by standard regulated negative DC voltage ranging from -17.5VDC to -26VDC supplied by matched Bently proximitor unit, consistent with universal 3300XL series sensor power specification. This 8mm standard probe keeps fixed factory-set calibrated sensitivity and defined effective linear measuring range complying with Bently original design standard. Premium high-temperature insulating material inside probe encapsulation and coaxial cable ensures outstanding insulation resistance to suppress signal drift caused by damp penetration or lubricant oil soaking. Double-layer full shielded coaxial inner structure of integral armored cable restrains external electromagnetic interference from surrounding high-voltage cables and frequency conversion equipment during signal transmission. Only factory-specified matching proximitor and corresponding calibrated 2789 model extension cable can be assembled with this probe to retain original factory calibration and measuring precision unchanged.
5. Environmental Working Parameters
The continuous allowable operating temperature of probe body ranges from -40 degrees Celsius up to +177 degrees Celsius, fitting high-temperature installation near bearing pedestals and internal equipment compartments of turbines and compressors. Spare part storage ambient temperature is controlled between -55 degrees Celsius and +95 degrees Celsius under dry non-condensing storage condition. Applicable working relative humidity covers 5%RH to 95%RH, and dew condensation penetrating into probe encapsulation and cable inner structure is strictly prohibited to prevent insulation deterioration and internal short-circuit fault. The armored probe assembly can withstand regular industrial running vibration from 10Hz to 2kHz generated by operating rotating equipment; long-term continuous exposure to strong corrosive chemical gas and persistent high-temperature steam immersion is forbidden to extend service life of internal sensing coil and insulating materials. For installation locations above 1000 meters altitude, properly shortening routine equipment inspection cycle is recommended for better thermal dissipation management.
6. Installation and Routine Maintenance Guidance
The probe is equipped with standard external mounting thread for threaded hole screwing installation on bearing support or customized fixed bracket. Field commissioning technicians adjust probe screwing depth carefully to set proper initial installation clearance between probe tip and target metal surface according to onsite construction technical documents. During periodic routine maintenance work, maintenance personnel shall regularly inspect probe mounting tightness, outer armor integrity, cable sheath damage status and connector locking tightness to eliminate hidden intermittent signal faults induced by loose connection or cable aging damage. If on-site probe failure needs component replacement, only spare probe with identical part number 27890-1-00-40-50-2 is permitted for direct swapping; using mismatched specification alternative products will lead to linearity deviation and inaccurate measurement data. All replacement spare probes complete full factory parameter recalibration and alternating high-low temperature aging test before outgoing delivery to guarantee full interchangeability during unit overhaul and system maintenance.
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