Description
Bently 991‑25‑50‑01‑00
Technical Specifications:
- Matching Sensor: 3300 NSv probe and extension cable, total electrical length 5 meters
- Full‑Scale Measuring Range: ‑0.25 mm ~ +0.25 mm axial displacement
- Power Supply: Two‑wire loop power +12 VDC ~ +35 VDC
- Output Signal: 4‑20 mADC two‑wire
- Loop Accuracy: ±1.5% full‑scale
- Sensitivity: 7.87 V/mm
- Frequency Response: 0‑10 kHz
- Prox‑Out Diagnostic Terminal: Gap‑voltage output available
- Maximum Loop Resistance: 1000 Ω @35 VDC
- Mounting: 35 mm DIN‑rail clip or panel screw mounting
- Operating Temperature: ‑40 °C ~ +85 °C
- Humidity: 0‑95% RH non‑condensing
- Startup‑inhibition function, output holds NOT‑OK state within 2‑3 seconds after power‑on Functional Features:
- Integrated proximitor circuit, NSv probe directly connects into transmitter, no external proximitor needed.
- Two‑wire loop mode shares single cable pair for power supply and signal transmission, reduces field wiring cost.
- On‑board zero‑point and span potentiometer supports on‑site calibration adjustment.
- Dedicated test‑input terminal enables loop verification without physical sensor connection.
- Built‑in sensor fault detection, output locks to fault‑level current when probe open‑circuit or short‑circuit happens to prevent system false alarm.
- Prox‑Out diagnostic terminal provides raw gap‑voltage measurement for fast field troubleshooting.
- Potted sealed construction, suitable for cabinet environment with high humidity. Application Scenarios: Axial thrust‑position monitoring for small‑clearance compressors, high‑speed pumps and turbines; equipment modification without TSI rack‑based protection system; OEM unit matching; hazardous‑area field signal conversion feeding control‑system. Performance Parameters: Linear error ≤ ±1.5% FS; fault response time less than 200 ms; strong anti‑electromagnetic‑interference performance; low temperature drift across operating temperature range. Material Composition: Flame‑retardant potting compound; multi‑layer PCB circuit board; high‑precision signal conditioning chip; gold‑plated signal terminals; flame‑retardant plastic housing; metal DIN‑rail spring clip; silicone sealing gaskets. Structural Characteristics: Standard DIN‑rail rectangular housing; front‑side wiring terminal block; calibration potentiometer access window; rear spring‑loaded DIN‑rail locking clip; housing surface printed with model, full‑scale range and unique serial number. Working Principle: Internal high‑frequency excitation circuit outputs high‑frequency AC signal to NSv proximity probe coil. Axial shaft movement changes gap distance between probe and metal shaft target. Eddy‑current intensity on target surface changes accordingly and leads to coil impedance variation. Transmitter internal circuit converts impedance variation into actual axial‑displacement engineering value and outputs 4‑20 mA loop‑current signal. Fault‑diagnosis circuit monitors sensor loop health continuously. Prox‑Out terminal outputs DC gap‑voltage value for maintenance inspection. Installation Requirements:
- Install transmitter onto 35 mm DIN‑rail, confirm rear locking clip fully engaged.
- Strictly respect two‑wire loop polarity. Never feed AC voltage to loop terminals.
- Total electrical length of NSv probe plus extension cable must strictly keep 5 meters matching factory calibration setting.
- Sensor signal cable and 4‑20 mA output cable shall run separately away from high‑power motor and inverter power cables.
- Complete zero‑point and span calibration via test‑input terminal after installation. Usage Notes:
- Prohibit cutting or welding NSv probe and extension cable, modified electrical length will destroy measurement linearity.
- Keep potentiometer position marked after calibration; avoid random adjustment during normal running status.
- Do not exceed maximum allowable loop resistance, otherwise 4‑20 mA output will become distorted.
- Periodically measure gap‑voltage value during equipment inspection to find out connector loose and cable aging risks ahead of failure.
