Product Details
The Bently Nevada 21508-02-12-10-02, also cataloged as the 21508 Proximity Sensors, operates as a dedicated hardware component for non-contact dynamic vibration and axial position measurement within machinery protection systems.
Suffix Breakdown & Model Matrix
| Option Field | Code | Configuration Detail |
|---|---|---|
| Thread Option | 02 | 3/8-24 UNF thread format |
| Unthreaded Length | 12 | 1.2 in unthreaded length |
| Overall Case Length | 10 | 1.0 in case length |
| Total Cable Length | 02 | 1.0 m (39 in) integral cable length |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 21508-02-12-10-02 |
| Brand | Bently Nevada |
| Origin | USA |
| Weight | 0.04 kg (0.09 lbs) |
| Dimensions | 8 mm probe tip diameter, 3/8-24 UNF reverse mount body |
| Operating Temp | -51 deg C to +177 deg C (-60 deg F to +351 deg F) |
| Power Consumption | Passive transducer powered via Proximitor Sensor loop |
| Mounting Type | Reverse mount 8 mm proximity probe |
| Cable Type | 1.0 m (39 in) integral cable with miniature male coaxial connector |
| Probe Scaling | Standard 7.87 V/mm (200 mV/mil) with matching Proximitor Sensor |
Eddy-Current Probe Scaling and Gap Voltage Validation
The 21508-02-12-10-02 reverse-mount probe utilizes high-frequency eddy-current probe scaling to convert target gap distances into linear electrical voltages. When driven by a matched Proximitor Sensor, the output yields a nominal scale factor of 7.87 V/mm (200 mV/mil) for ferromagnetic targets such as AISI 4140 steel. Setting the mechanical installation bias to achieve -10 VDC gap voltage validation establishes the sensor at the midpoint of its calibrated linear range, providing symmetric headroom for high-amplitude dynamic vibration analysis and precise rotor dynamics tracking.
Frequently Asked Questions
Q: How is the miniature male coaxial connector insulated from machine electrical ground?
A: The connector terminal must be fitted with a high-dielectric silicone insulator boot to prevent grounding of the coaxial outer conductor at the machine casing.
Q: What is the primary functional difference of the reverse-mount housing configuration?
A: The reverse-mount body is threaded from the rear, allowing the transducer to be installed through internal bearing housings or mounting brackets where front-access clearance is limited.
Field Installation Guidelines
- Thread the reverse-mount probe body into the tapped mounting bracket or sleeve inside the bearing housing.
- Advance the sensor tip toward the target shaft surface while measuring DC voltage across the Proximitor Sensor output terminals.
- Lock the mounting jam nut once the multimeter indicates the target gap voltage of -10 VDC.
- Route the integral 1.0 m cable away from sharp edges, hot surfaces, and high-voltage power leads.
- Connect the miniature male coaxial connector to the Proximitor extension cable and slide a protective insulating sleeve over the connector junction.
Additional Information
- 100% Genuine Parts: All products are original and authentic, ensuring reliable industrial performance.
- 30-Day Refund Guarantee: Return any in-stock item within 30 days in original, unopened packaging for a full refund (excluding shipping and fees).
- 12-Month Warranty: Covers defects in materials or workmanship; excludes misuse, normal wear, or unauthorized modifications.
- Worldwide Shipping: We ship via USPS, UPS, FedEx, and DHL. Delivery times vary by country and may be subject to customs or import fees.
- Support & Contact: Technical and warranty assistance is available anytime. Contact us here: Contact.
- Purchase Guidance: Check product specifications and compatibility carefully before ordering to ensure proper application.
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