Bently Nevada 24653-2-1-25-50-2 Proximitor Preamplifier Product Specification
24653-2-1-25-50-2 is a factory pre-calibrated heavy-duty high-temperature proximitor preamplifier developed for Bently Nevada large-range 3300XL eddy current proximity transducer system. It serves as the core signal conditioning unit bridging large-size proximity probes and rack-mounted 3300 or 3500 series machinery monitoring modules, widely deployed for critical parameter measurement on steam turbines, gas turbines, large centrifugal compressors and heavy-duty turbo-generators in power generation, petrochemical and metallurgical industries. This proximitor generates high-frequency excitation signal to drive matched 25 mm and 50 mm proximity probes simultaneously, converting impedance changes induced by physical gap variation between probe tip and metallic target into stable linear DC analog voltage output. The conditioned analog signal is delivered to backend monitor boards to accomplish continuous measurement of rotor axial displacement, casing differential expansion and valve stem travel, supporting over-limit pre-alarm and emergency shutdown interlock protection to avoid catastrophic unit breakdown caused by excessive mechanical displacement. Every finished unit passes strict linearity calibration, insulation resistance testing and alternating high-low temperature cycling aging test before factory delivery to maintain consistent measuring accuracy under harsh field conditions with high ambient temperature, dense lubricant oil mist and complicated electromagnetic interference near hot turbine casings and local junction boxes.
Description
Bently Nevada 24653-2-1-25-50-2 Proximitor Preamplifier Product Specification
1. Product Overview
24653-2-1-25-50-2 is a factory pre-calibrated heavy-duty high-temperature proximitor preamplifier developed for Bently Nevada large-range 3300XL eddy current proximity transducer system. It serves as the core signal conditioning unit bridging large-size proximity probes and rack-mounted 3300 or 3500 series machinery monitoring modules, widely deployed for critical parameter measurement on steam turbines, gas turbines, large centrifugal compressors and heavy-duty turbo-generators in power generation, petrochemical and metallurgical industries. This proximitor generates high-frequency excitation signal to drive matched 25 mm and 50 mm proximity probes simultaneously, converting impedance changes induced by physical gap variation between probe tip and metallic target into stable linear DC analog voltage output. The conditioned analog signal is delivered to backend monitor boards to accomplish continuous measurement of rotor axial displacement, casing differential expansion and valve stem travel, supporting over-limit pre-alarm and emergency shutdown interlock protection to avoid catastrophic unit breakdown caused by excessive mechanical displacement. Every finished unit passes strict linearity calibration, insulation resistance testing and alternating high-low temperature cycling aging test before factory delivery to maintain consistent measuring accuracy under harsh field conditions with high ambient temperature, dense lubricant oil mist and complicated electromagnetic interference near hot turbine casings and local junction boxes.
2. Part Number Definition Breakdown
Each segmented code of 24653-2-1-25-50-2 corresponds to fixed factory-defined configuration parameters. The base code 24653 represents the dedicated large-range dual-specification proximitor series designed for 25 mm and 50 mm oversized eddy current probes; the second segment 2 defines mechanical enclosure type with screw-mounted fixing structure and fully sealed cast metal housing specification; the third segment 1 stands for standard internal circuit layout and non-explosion-proof electronic configuration confirmed by original factory setting; the fourth segment 25 specifies factory calibration parameters matching 25 mm diameter proximity probe with corresponding linear range; the fifth segment 50 defines preset calibration data compatible with 50 mm oversized proximity probe; the final segment 2 denotes fixed hardware revision, terminal layout and production calibration version. Any proximitor with mismatched segment codes carries different locked calibration parameters and cannot be directly interchanged on-site without full-loop professional recalibration, which will trigger severe measurement deviation and incorrect protection action of the whole monitoring loop.
3. Core Functional Characteristics
Adopting high-temperature resistant high-frequency oscillating circuit design, the proximitor provides stable high-frequency driving source for both 25 mm and 50 mm matched proximity probes, realizing linear conversion from clearance fluctuation into proportional DC voltage within respective specified measuring span. Built-in multi-stage filtering network effectively suppresses power frequency interference and high-frequency clutter generated by adjacent high-voltage cables and variable-frequency drive equipment to minimize signal distortion during long-distance calibrated extension cable transmission. Fully enclosed cast aluminum metal housing delivers outstanding high-temperature resistance, oil-proof, dust-proof and anti-vibration capability, allowing reliable installation inside compact field junction boxes close to high-temperature turbine casing and bearing compartments. When assembled with original factory-certified proximity probes and matched calibrated extension cables, the complete transducer system maintains fixed linear scale factor for two different probe specifications separately, enabling backend monitoring modules to configure independent pre-alarm and critical trip thresholds for axial displacement and differential expansion protection. Abnormal open-circuit or short-circuit faults on field probe wiring can be rapidly identified through obvious output voltage drift to simplify on-site troubleshooting and routine maintenance work.
4. Electrical and Metrological Specifications
The proximitor operates on regulated negative DC input power ranging from -17.5 VDC to -26 VDC, normally supplied at -24 VDC from matched rack monitoring modules or dedicated regulated DC power supply. Factory-locked calibrated sensitivity differs for two applicable probes: 0.787 V/mm for 25 mm proximity probe and 0.394 V/mm for 50 mm oversized proximity probe, with overall linear tolerance controlled within ±5% conforming to API 670 industry standard. Its valid linear measuring range covers 2.5 mm to 27.5 mm for 25 mm probe configuration and 5 mm to 55 mm for 50 mm probe configuration respectively. The output signal combines DC component for static displacement reading and AC component for dynamic vibration measurement, with effective working frequency response ranging from DC up to 8 kHz to satisfy both slow differential expansion monitoring and high-frequency vibration acquisition requirements. Standard screw terminal block is arranged for orderly field wiring of power supply line, probe input cable and analog signal output cable; arbitrary cutting or replacement with non-calibrated unmatched cables will invalidate original factory calibration data and damage overall measurement precision of the entire transducer loop.
5. Environmental Working Parameters
Continuous permissible operating ambient temperature of the proximitor ranges from -40°C up to +121°C to adapt high-temperature installation near heated turbine casing and bearing housing positions. Spare storage temperature is controlled between -55°C and +85°C under dry non-condensing storage environment; applicable working relative humidity spans 5%RH to 95%RH, and internal dew condensation inside metal enclosure is strictly prohibited to prevent internal circuit corrosion and short-circuit failure. The unit can withstand regular industrial running vibration of 10 Hz to 2 kHz generated by nearby rotating equipment. Long-term continuous exposure to strong corrosive gas and persistent hot steam immersion is forbidden to extend service life of internal electronic components. For installation above 1000 meters altitude, properly shorten routine inspection cycle for regular working condition check.
6. Installation and Routine Maintenance Guidance
Mounting holes are pre-reserved on the metal housing for rigid bolt fastening onto flat junction box base or customized equipment mounting bracket. During field wiring construction, separate signal transmission cables away from high-current AC power lines to avoid cross electromagnetic coupling interference and fully tighten all terminal fixing screws to eliminate intermittent signal fluctuation caused by loose wiring contact. In periodic maintenance activities, maintenance personnel regularly inspect enclosure surface integrity, terminal tightening status and surrounding oil accumulation condition around installation location. If on-site device failure requires component replacement, only spare part with identical full part number 24653-2-1-25-50-2 is permitted for direct swap. All replacement preamplifiers complete full electrical performance testing and alternating high-low temperature aging screening before factory delivery to guarantee full interchangeability during equipment overhaul and system maintenance.
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