Bently Nevada 21000-05-10-00-026-03-02 Armored Eddy Current Probe Assembly Product Specification

The 21000-05-10-00-026-03-02 is a factory pre-calibrated heavy-duty armored eddy current proximity probe under Bently Nevada 21000 series integrated armored probe product family, developed for embedded installation inside bearing pedestals of critical rotating machinery under harsh working conditions with high temperature, heavy lubricating oil mist and complicated mechanical stress. This unit adopts integrated metal armored sleeve structure with built-in standard 3300XL proximity sensing core. When matched with original designated proximitor and supporting extension cable, it forms a complete non-contact displacement measurement system fully compliant with API 670 machinery protection standards. Widely applied on steam turbines, heavy-duty gas turbines, large centrifugal compressors and turbo-generator units in power, petrochemical and metallurgical sectors, the probe continuously measures shaft radial vibration and axial thrust displacement as well as keyphasor rotational speed. It outputs over-limit alarm and emergency trip interlock signals to protect rotating equipment from severe damage caused by abnormal operating conditions. Every finished assembly undergoes full-span linear calibration, high-low temperature cyclic aging test and hermetic sealing inspection prior to factory release to retain consistent measurement precision during long-term field service.

The seven-digit coded designation follows Bently’s unified specification for armored proximity probe configuration definition. The leading code 21000 represents heavy-duty armored probe series equipped with integral anti-oil, anti-impact metal protective casing; the second code 05 stands for probe core specification matched with standard 5mm diameter 3300XL sensing element and matched aluminum alloy armored housing; the third code 10 indicates fixed factory-molded integral coaxial cable with total length of 10 meters, and field cutting or random modification on the original cable is prohibited to preserve factory calibrated electrical parameters; the fourth code 00 means zero exposed probe tip outside the front end of armored sleeve, with the entire sensing tip fully recessed inside the protective sleeve for anti-collision and anti-scratch protection; the fifth code 026 defines total armored sleeve length of 2.6 inches, suitable for shallow embedded mounting on compact bearing housings; the sixth code 03 specifies 3/4-14 NPT tapered pipe thread as standard mounting thread for bearing base installation holes; the final suffix code 02 refers to standard rear industrial sealing design together with miniature coaxial plug connector without special explosion-proof certification, delivered with original factory calibration configuration. Replacing with mismatched part number probes will invalidate original factory calibration and result in measurement drift or undesired protection channel tripping.

The armored sleeve and front protection structure are precision manufactured from high-strength corrosion-resistant stainless steel, providing excellent resistance against lubricant corrosion, high-temperature oil vapor and accidental mechanical impact inside sealed bearing chambers. The internal induction coil of the sensing core is fully encapsulated with high-temperature resistant epoxy resin to eliminate internal air gaps, effectively preventing coil displacement and inter-turn short-circuit failures induced by long-running equipment vibration and fluctuating ambient temperature. The attached 10-meter original integral coaxial cable adopts standard 75-ohm controlled impedance construction with over 95% coverage tinned copper braided shielding to suppress external electromagnetic interference during signal transmission. Any field cutting, splicing or arbitrary replacement of original cable and tail connector is strictly forbidden, as physical alteration will permanently void factory preset calibration data of the whole measurement set. The fully recessed probe tip design optimizes the product for shallow bore installation on compact bearing seats, avoiding tip abrasion during assembly and equipment operation. Equipped with built-in open-circuit and short-circuit diagnostic function, the probe can feed back abnormal wiring status via obvious output voltage deviation to simplify daily on-site troubleshooting. Stable linear measuring performance of the whole monitoring system can only be guaranteed by original matching of this probe, certified extension cable and designated compatible proximitor.

The matched proximitor requires regulated negative DC supply ranging from -17.5 VDC to -26 VDC, with -24 VDC defined as nominal standard operating voltage for regular industrial field use. Factory calibrated sensitivity is fixed at 7.87 V/mm (200 mV/mil) based on AISI4140 carbon steel target, and full-range linearity error is controlled within ±5% per API 670 requirements. Valid linear measurement range covers 0 mm to 1.27 mm to satisfy regular radial vibration and axial clearance measurement for medium and small diameter high-speed rotating shafts. Frequency response ranges from DC to 10 kHz, capable of capturing both low-frequency static thermal expansion drift and high-frequency dynamic vibration signals synchronously. The recommended installation gap is set near the midpoint of linear range to maintain stable DC bias working point for uninterrupted long-term equipment operation.

The sensing assembly allows continuous working temperature from -35°C to +120°C to adapt high-temperature surroundings close to heated bearing housings and turbine casings. Storage temperature for spare probes is maintained between -55°C and +85°C under dry non-condensing environment; applicable working relative humidity ranges from 5%RH to 95%RH without dew condensation on probe housing and cable outer sheath. The probe can endure periodic industrial vibration from 10 Hz to 2 kHz generated by adjacent running rotating machinery. Long-term continuous immersion or exposure to corrosive liquid, acid mist and sustained high-temperature steam is not allowed to prevent casing rust and premature aging of internal insulation materials. For installation locations above 1000 meters altitude, shorten routine inspection cycle appropriately.

Disconnect all power supply of the monitoring loop before field installation, screw the threaded probe body into pre-machined mounting hole of bearing pedestal or customized fixture through standard 3/4-14 NPT thread, adjust installation clearance to rated design value and tighten lock nut firmly to avoid loosening caused by long-period operational vibration. During cabling layout, separate probe signal cable away from high-current AC power cables and inverter output wiring to minimize cross electromagnetic coupling interference. Prevent sharp small-radius bending, excessive stretching and heavy compression on cable to avoid inner conductor fracture and abnormal impedance variation. Within fixed maintenance cycles, regularly inspect cable outer jacket for oil corrosion, abrasion and cracking, and check fastening tightness of rear terminal connector. When replacement becomes necessary after probe failure, only spare part with identical part number 21000-05-10-00-026-03-02 is allowed for direct replacement. All replacement units complete full electrical testing and alternating temperature aging screening before factory delivery to ensure full interchangeability inside original vibration monitoring loops.