Product Overview
When rotating machinery reliability is non-negotiable, the Bently Nevada 21000-28-05-20-039-04-02 provides a robust mounting solution for 3300 XL 8 mm proximity probes. This industrial automation module is engineered for permanent installation in harsh environments, protecting sensitive vibration sensors while maintaining precise gap measurements. The 21000-28-05-20-039-04-02 combines an aluminum body with a 304 stainless steel sleeve, delivering both corrosion resistance and structural integrity for continuous operation.
This housing assembly is part of the 21000 series, designed specifically for externally mounted proximity probes. It includes a dome cover, threaded conduit ports, a probe sleeve, O-rings, a reverse mount probe, and a thread seal—everything needed for a secure, repeatable installation. The unit ships new in original factory packing, backed by a 12-month warranty.
Technical Specifications
The Bently Nevada 21000-28-05-20-039-04-02 is configured with the following key parameters:
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Probe Option: 3300 XL 8 mm probe with connector, selectable hazardous area approvals
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Probe Cable Length: 0.5 m (20 in)
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Standoff Adapter: 2 in
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Probe Penetration: 3.9 in
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Fitting Option: One 3/4-14 NPT plug only
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Mounting Thread: 3/4-14 NPT
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Material: Aluminum body with 304 stainless steel sleeve
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Weight: 1.1 kg (2.4 lb) typical, without fittings
With a probe cable length of 0.5 m, the maximum (C) + (D) dimension is 13.5 in (34.3 mm) when the probe is not visible. This compact geometry simplifies installation in confined spaces.
Industry Applications
The 21000-28-05-20-039-04-02 excels in critical rotating equipment monitoring, including turbines, compressors, and pumps. Its CSA Type 4 enclosure rating ensures reliable operation in washdown or dusty environments. For example, in a refinery, this housing allows a 3300 XL probe to monitor shaft vibration on a large centrifugal compressor, even in a Class I, Division 2 area. The aluminum body provides excellent thermal conductivity, while the stainless steel sleeve resists process media corrosion—a key advantage over standard housings in chemical plants.
Installation & Setup Guidance
Proper installation is critical for accurate vibration readings. Begin by verifying the mounting thread (3/4-14 NPT) matches the machine port. Install the standoff adapter (2 in) to position the probe correctly, then thread the housing into place. Insert the 3300 XL 8 mm probe through the sleeve, adjusting penetration to 3.9 in as specified. Secure the dome cover and connect the conduit fitting. Ensure the cable length (0.5 m) provides enough slack without stressing the connection. Finally, verify the gap voltage using a proximity probe calibrator to confirm the target position.
Maintenance & Reliability
Routine inspection of the 21000-28-05-20-039-04-02 ensures long-term reliability. Check the O-rings and thread seal for wear every 12 months, especially in high-vibration environments. Clean the dome cover and conduit ports to prevent debris accumulation. The 304 stainless steel sleeve resists corrosion, but verify the aluminum body for pitting in aggressive atmospheres. By following a preventive maintenance schedule, you extend housing life and avoid unplanned downtime—a direct cost saving for any plant.
Selection Guide & Purchasing Advice
Before ordering, confirm your probe model (3300 XL 8 mm) and required cable length. The 21000-28-05-20-039-04-02 includes a 2 in standoff adapter and 3/4-14 NPT mounting thread; if your application differs, select the appropriate suffix codes. Ensure the fitting option (one NPT plug) matches your conduit plan. PLC Source PRO offers this new, factory-packed unit with a 12-month warranty, ensuring you receive a genuine Bently Nevada product. For volume pricing or expedited shipping, contact our sales team.