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        81725-02

        / 4.9
        1001 reviews ｜ Need a Specific Revision?
        The Bently Nevada 81725-02 is a 14 mm Proximitor® sensor in the 7200 series, converting probe signals into precise negative DC voltage outputs. It enables accurate, non-contact displacement measurement for vibration, shaft position, and rod drop monitoring on rotating and reciprocating machinery.
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        Warranty Policy
        We provide 1 year warranty for all remaining parts.
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        Return Notice
        The warranty period is one year from the date of shipment, unless otherwise stated in the parts description. We guarantee that the project will not exhibit functional defects that may occur under normal operating conditions during the warranty period.
        In the event of a defect, we will send new equipment, repair equipment or refund the purchase price based on our availability. You must contact us to obtain a return authorization and return the defective device to us within 14 days of reporting the defect.
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        Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.Various transportation options are available in each country. Shipping methods and fees are clearly indicated on all quotations.
        Parts Availability
        Apter Power offers a wide range of components, products and services related to industrial automation. We also supply new products from a variety of quality manufacturers.
        How to order
        We have been working hard to update our inventory. If we have stock or parts available for new factory purchases, you can contact the order online. If we do not currently have an inventory, the displayed quantity will show "Ask". Please create an online quote or contact us by phone, fax or email to check availability.

        Technical specifications for 81725-02

        • Manufacturer:
          Bently Nevada
        • Part Number:
          81725-02
        • Product Family:
          7200 Proximity Transducer Systems
        • Probe dia.:
          14 mm (.551 in.)
        • Cable length:
          9 m (29.5 ft.)
        • Scale factor:
          100 mV/mil (4 V/mm)
        • Load:
          10 kΩ
        • Target Material:
          AISI 4140 steel
        • Input:
          -18 Vdc to -24 Vdc at 13 mA maximum.
        • Linear Range:
          4.06 mm (160 mils). Linear range begins at approximately 0.508 mm (20 mils) from target and is from 0.508 to 4.57 mm (20 to 180 mils).
        • Recommended Gap Setting:
          2.54 mm (100 mils).
        • Operating Temperature:
          -51.1°C to +100°C (-60°F to+212°F).
        • Relative Humidity:
          100%, condensing, non-submersible when connectors are protected.
        • Weight:
          0.55 kg
        • Estimated shipping dimensions:
          24.3x4.6x15.5cm
        • Tariff Code:
          8536200000
        • Country of origin:
          USA
        • Place of shipment:
          Xiamen, Fujian, China
        By purchasing this item, you agree to the Terms & Conditions, ApterPower is not an authorized distributor for listed manufacturers or tradenames and therefore the manufacturer's warranty does not apply. All our products come with ApterPower's 1-year warranty.

        More Information

        Overview Manuals Specifications Troubleshooting Installation Requirements Applications

        Features:

        • Converts Non-Contact Probe Signals Into Accurate Negative DC Voltage Outputs.
        • Supports Wide Linear Range With Recommended Gap Setting For Precise Displacement Measurements.
        • Designed For Harsh Industrial Conditions With High Temperature And Humidity Tolerance.
        The Bently Nevada 81725-02 14 mm Proximitor® sensor is a core component of the 7200 series, providing highly accurate non-contact measurement of rotor and shaft displacement. By converting the probe signal into a negative DC voltage, it enables precise monitoring of machinery motion, including vibration and axial thrust. Its design allows operators to detect early signs of mechanical issues, supporting predictive maintenance strategies and reducing unplanned downtime. The sensor’s non-contact operation also minimizes wear on critical components, extending the service life of monitoring systems.

        In industrial applications, the 81725-02 is versatile and can be applied to turbines, compressors, and other rotating machinery where accurate shaft position and vibration analysis are crucial. It integrates seamlessly with 3300 and 3500 monitoring systems to provide real-time diagnostics. Operators can track eccentricity, vibration amplitude, and phase, as well as Keyphasor® signals, offering comprehensive insight into machinery health. This level of detail helps prevent failures, optimize maintenance schedules, and ensure operational safety.

        Beyond traditional vibration monitoring, the sensor supports advanced measurements such as rod drop for reciprocating compressors, providing actionable data on wear patterns and alignment issues. Its reliable performance in harsh environments, including high humidity and wide temperature ranges, makes it suitable for demanding industrial settings. By providing consistent, high-resolution data, the 81725-02 enhances decision-making, improves asset utilization, and contributes to long-term cost savings for plant operations.

        The 81725-02 Bently Nevada 14 mm Proximitor® Sensor may still be available for purchase and support from Apter Power beyond End-Of-Life (EOL) by the manufacturer (OEM).
        Bently Nevada 81725-02 14 mm Proximitor® Sensor Manuals,Datasheets,Link Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
        Bently Nevada 81725-02 14 mm Proximitor® Sensor Specs

        General

        • Manufacturer GE / Bently Nevada
        • Model 81725-02
        • Condition New Original ready stock
        • Product Family 81728-02,81728-01,81727-02
        Important Notice: Other accessories, manuals, cables, calibration data, software, etc. are not included with this equipment unless listed in the above stock item description. All prices are shown in USD.
        • Gap Voltage Check: Measure the DC voltage at the output terminals (OUT and COM) using a multimeter. If the voltage is at extreme values ​​(e.g., -1V or -22V), it usually indicates that the gap between the probe and the surface being tested is too small or too large.
        • OK Loop Monitoring: Check the OK indicator light on the monitor. If it is off, confirm that the preamplifier power supply is between -17.5 Vdc and -26 Vdc.
        • Connectivity Test: Disconnect the probe cable and measure the resistance on the probe side (usually a low resistance value). If an open circuit (infinite) or short circuit is observed, it indicates that the extension cable or probe is damaged.
        • Scale Factor Verification: Move the probe on the calibration bench and observe whether the output voltage change conforms to the standard linear scale of 3.94 V/mm (100 mV/mil).
        • Matching Verification: The total length of the 81725-02 preamplifier, extension cable, and 14 mm probe must match (typically a 5-meter or 9-meter system). Failure to do so will result in significant deviations in measurement linearity.
        • Insulated Installation: The preamplifier housing typically needs to be insulated from the rack ground. It is recommended to install it on a dedicated insulated rail or mounting plate to prevent ground loop interference.
        • Cable Protection: Extension cable connectors (coaxial connectors) must be wrapped with heat-shrink tubing to prevent contact with the housing ground or corrosion from oil.
        • Gap Preset: When installing the probe, the initial gap voltage must be adjusted to the linear midpoint (typically around -10V) according to process requirements and secured with a lock nut.
        • Large Axial Displacement Monitoring: Due to the wider linear range of the 14 mm probe compared to the standard 8 mm probe, it is commonly used for axial (thrust) displacement monitoring in large steam turbines and compressors.
        • Large-diameter shaft radial vibration: Suitable for rotating machinery bearing housings with large shaft diameters, slightly higher surface roughness, or where longer measurement distances are required due to installation space limitations.
        • Differential Expansion Measurement: Used to measure the relative thermal expansion between the rotor and the casing during turbine startup.
        • Eccentricity Measurement: Monitors the degree of bending of the large rotor during low-speed turning gear operation to ensure safe startup.
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        Description
        The 81725-02 14 mm Proximitor® sensor is a core component of the Bently Nevada 7200 series eddy current sensor system. It receives radio frequency signals from its probe tip and translates them into a negative DC voltage proportional to the distance from the observed metal target, enabling precise monitoring of shaft and rotor behavior.

        This sensor operates with an input of -18 Vdc to -24 Vdc at a maximum of 13 mA and supports a 10 kΩ load. Its linear measurement range spans 0.508 mm to 4.57 mm (20 to 180 mils), with a recommended gap setting of 2.54 mm (100 mils). Designed for industrial environments, it functions within -51.1°C to +100°C (-60°F to +212°F) and tolerates 100% condensing relative humidity when connectors are protected.

        Equipped with a 9 m (29.5 ft.) coaxial cable and a probe diameter of 14 mm (.551 in.), the sensor offers a scale factor of 100 mV/mil (4 V/mm) and is optimized for targets made of AISI 4140 steel. It accurately measures radial vibration, axial thrust, and shaft position on large machinery, providing critical data for predictive maintenance and operational safety.

        All 7200 series proximity transducers, including the 81725-02, are compatible with 3300 and 3500 Monitoring Systems. The system can provide advanced measurements such as eccentricity, vibration amplitude and phase, Keyphasor® signals, and rod drop, enabling detailed diagnostic analyses of machinery performance.

        By integrating with Bently Nevada 3300/3500 monitors, the 81725-02 ensures real-time, reliable monitoring of rotating equipment. Its non-contact design reduces wear and extends system longevity while delivering high-precision data critical for industrial asset protection.
        Alternative Names
        81725-01 81725-03 81725-04 81726-01 81726-02
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        FAQS

        The following is a list of questions commonly asked by our customers. Please contact us if you have a question about our process that is not answered below.
        VIEW ALL FAQS
        How is the 81725-02 sensor powered?
        The sensor operates with an input of -18 Vdc to -24 Vdc at a maximum of 13 mA.
        What is the linear range of the 81725-02?
        The linear range is from 0.508 mm to 4.57 mm (20 to 180 mils), starting approximately 0.508 mm from the target.
        How does the recommended gap setting affect measurements?
        A recommended gap of 2.54 mm (100 mils) ensures maximum sensitivity while maintaining the sensor’s linear accuracy.
        Which environmental conditions can the sensor tolerate?
        Operating temperature is -51.1°C to +100°C (-60°F to +212°F) with up to 100% condensing relative humidity, non-submersible when connectors are protected.
        How should it be installed to handle high humidity?
        Proper sealing of connectors and routing away from water exposure ensures consistent performance in humid industrial environments.

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