Bently Nevada 18745-01 Proximitor Detailed Product Specification
18745-01 is a factory single-calibrated eddy-current proximitor belonging to Bently Nevada classic 7200 transducer series, manufactured in the United States as the core signal conditioning component of three-piece non-contacting proximity measurement system composed of proximity probe, matched extension cable and proximitor unit. Distinguished from universal dual-purpose 18745-03 and high-temperature customized 8mm dedicated 18745-04 variants, this model is exclusively pre-calibrated for standard 5mm diameter 330101 series eddy-current probes and cannot be matched with 8mm probes without official factory recalibration, making it the standard dedicated spare for small-diameter proximity monitoring loops across power, petrochemical and heavy industry fields. Following eddy-current inductive measurement principle, it converts variable clearance between conductive rotating target and probe tip into linear negative DC output voltage, transmitting processed measuring signals to Bently 3300/3500 rack monitoring modules, local field indicators and plant DCS/PLC control system to realize continuous real-time monitoring of radial shaft vibration, axial thrust displacement and rotor differential expansion in compliance with API 670 global machinery protection standard.
Description
Bently Nevada 18745-01 Proximitor Detailed Product Specification
1. Product Overview
18745-01 is a factory single-calibrated eddy-current proximitor belonging to Bently Nevada classic 7200 transducer series, manufactured in the United States as the core signal conditioning component of three-piece non-contacting proximity measurement system composed of proximity probe, matched extension cable and proximitor unit. Distinguished from universal dual-purpose 18745-03 and high-temperature customized 8mm dedicated 18745-04 variants, this model is exclusively pre-calibrated for standard 5mm diameter 330101 series eddy-current probes and cannot be matched with 8mm probes without official factory recalibration, making it the standard dedicated spare for small-diameter proximity monitoring loops across power, petrochemical and heavy industry fields. Following eddy-current inductive measurement principle, it converts variable clearance between conductive rotating target and probe tip into linear negative DC output voltage, transmitting processed measuring signals to Bently 3300/3500 rack monitoring modules, local field indicators and plant DCS/PLC control system to realize continuous real-time monitoring of radial shaft vibration, axial thrust displacement and rotor differential expansion in compliance with API 670 global machinery protection standard.
2. Matching System Configuration Definition
The unit is preset at factory to exclusively pair with 330101 series 5mm proximity probes and supporting 330130 coaxial extension cables; total combined length of probe integral cable plus extension cable is fixed and pre-calibrated during production, with mainstream factory preset options of 5 meters and 9 meters full system cable length. Random field cutting, arbitrary replacement or mixed matching with non-designated 8mm probe assemblies will change the whole loop capacitance value, resulting in obvious sensitivity drift and linearity deviation that directly deteriorate measurement precision. Interconnection between probe tail and extension cable adopts gold-plated ClickLoc locking connector with outstanding anti-corrosion, anti-humidity and low signal attenuation characteristics, adapting to moderately corrosive and damp cabinet environment in refineries and power plant control rooms. No internal parameter adjustment can realize cross-spec probe switching on site, which is the core design feature separating this model from multi-purpose 18745-03.
3. Core Electrical Performance Parameters
Nominal input power supply ranges from -18VDC to -24VDC negative DC voltage, with -24VDC as recommended rated operating input, featuring low static power consumption to avoid excessive internal heat accumulation under long-term continuous running condition. Fixed factory calibration sensitivity is unified at 200mV/mil, equivalent to 7.87V per millimeter of gap variation between probe and target surface, consistent with the unified parameter standard of full 18745 serial products. Standard effective linear measuring range covers 80 mils (roughly 2mm valid clearance window), full-scale linearity error strictly controlled below 1% full span to guarantee high-precision detection of static shaft position offset and dynamic high-frequency vibration fluctuation. Its frequency response bandwidth covers DC (0Hz) up to 10kHz, supporting synchronous collection of steady-state axial displacement data, high-speed rotor radial vibration, shaft eccentricity and Keyphasor phase reference pulse signals without waveform distortion.
Output DC voltage changes linearly from near 0V to -24VDC corresponding to full calibrated clearance span; reserved dedicated test terminals on terminal block enable regular periodic field calibration and on-site fault troubleshooting without mandatory equipment shutdown. Built-in integrated protection circuits including reverse polarity prevention, overvoltage clamping, short-circuit and surge transient suppression effectively protect internal PCB components against damage caused by field wiring errors and instantaneous power grid fluctuation.
4. Mechanical Structure and Mounting Specification
Constructed with high-strength flame retardant industrial plastic housing, 18745-01 shares completely consistent outer dimension with other 18745 serial variants: 81.3mm in height × 61.2mm in width × 63.5mm in depth, net weight around 220 grams, enabling direct interchangeable replacement with 18745-03 and 18745-04 during spare part maintenance via identical mounting footprint without mechanical cabinet modification. A single power status LED indicator is set on front panel for intuitive energization inspection; lower section is divided into three independent screw wiring terminals with clear screen printing marks for power input, probe coaxial signal input and analog output respectively to minimize field wiring fault probability. All internal circuit boards receive full conformal coating treatment to resist dust deposition, ambient moisture and mild corrosive industrial gas erosion inside control cabinets, with enclosure protection grade IP20 only applicable for indoor cabinet installation rather than open-air splash-prone outdoor working environment. Two optional installation modes are available: standard DIN top-hat rail snap-on mounting or direct panel fixed installation with screw fasteners.
5. Environmental Operating Specifications
Continuous rated operating ambient temperature scope is -20℃ ~ +70℃ for regular indoor control cabinet installation; intermittent short-time overload operation allows working environment ranging from -40℃ up to +85℃ to adapt temporary high-temperature surroundings close to warm equipment casings. Storage and transportation temperature spans -40℃ ~ +125℃ to satisfy cross-regional spare part logistics delivery and long-term warehouse storage under extreme cold or hot climate conditions. Permissible operating relative humidity is limited within 5%~95% non-condensing condition to eliminate internal short-circuit risk triggered by cabinet dew formation and condensed damp air on circuit components.
6. Industrial Application Coverage
Targeted for 5mm probe matching measurement scenarios, this proximitor is widely deployed on medium and small-size rotating equipment including medium-pressure steam turbines, small centrifugal compressors, large industrial fans, feedwater pumps and auxiliary generators inside thermal power plants, petrochemical refining facilities, natural gas compression stations and metallurgical production lines. It monitors core operating parameters such as radial shaft vibration, rotor axial thrust position and differential expansion to capture early equipment hidden faults including rotor shaft rub, bearing fatigue abrasion and shaft alignment deviation in advance. When measured numerical value exceeds preset alert or danger threshold, linked monitoring system triggers local alarm signal or safety interlock shutdown to avoid costly catastrophic damage of core production equipment. Matched with Keyphasor transducers, it also provides rotating speed and phase reference data for post-failure spectrum analysis and equipment predictive maintenance trending analysis.
7. Certification and Warranty Terms
Original genuine 18745-01 complies with Bently Nevada internal factory quality control standards, CE electrical safety certification and API 670 international rotating machinery protection specification; factory original calibration certificate can be supplied upon customer request for incoming factory quality inspection procedure. When installed and wired strictly complying with specified electrical and environmental operating limits without artificial physical damage, reverse power polarity connection or overvoltage misuse, the product enjoys twelve-month limited manufacturer warranty starting from goods delivery date, covering inherent manufacturing defects of internal electronic components and circuit assembly. Customized ATEX Class I Division 2 explosion-proof version is available via special pre-order for installation inside classified hazardous explosive gas industrial sites.
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