Description
The Bently Nevada 21000-28-05-00-080-03-02 is a 3/8-24 UNF threaded eddy current proximity probe belonging to the legacy 7200 8mm series dynamic measurement family. It measures static and dynamic distance between the probe tip and a rotating shaft target—enabling precise oil-film vibration, axial position, and radial displacement tracking on high-speed critical machinery like steam turbines and centrifugal compressors.
Option Code Breakdown
- 21000: 3/8-24 UNF Thread, 8mm Tip Diameter Proximity Probe (Legacy 7200 Series)
- 28: Unthreaded Length Option (2.8 inches)
- 05: Overall Case Length Option (0.5 inches)
- 00: Connector Option (Standard miniature coaxial connector, miniature male click-lock style)
- 080: Total Length Option (8.0 meters / approximately 26.2 feet total system length calibration)
- 03: Fluid Seal / Armor Option (Includes flexible stainless steel armor conduit over the cable)
- 02: Agency Approval Option (Multiple international hazardous area certifications, including ATEX/IECEx)
Commercial Supply Status
- Condition: New Original (Factory Sealed)
- Availability: In stock
- Lead Time: Ships within 1–2 business days
- Warranty: 12-month industrial replacement warranty
- Price Policy: The market price of legacy 7200 series components varies depending on remaining factory stock allocation and regional compliance verification. The current listing is a reference benchmark. Contact our procurement desk to get a firm, negotiable commercial quotation.
Technical Parameters
| Parameter | Value |
| Probe Tip Diameter | 8.0 mm (0.315 in) |
| Thread Size | 3/8-24 UNF-2A |
| Nominal Linear Range | 2.0 mm (80 mils) |
| Scale Factor | 7.87 V/mm (200 mV/mil) when paired with 7200 Proximitor |
| Target Material | AISI 4140 steel (standard calibration target) |
| Operating Temperature | −35 to +177°C |
| Armor Outer Diameter | 5.8 mm (0.23 in) stainless steel braid sleeve |
Field Deployment Notes & Insights
During structural retrofits on an older gas turbine mid-frame housing, installing this legacy 8mm probe required extreme mechanical care. Well, technically the internal coaxial core is robustly insulated, but if you twist the 8.0-meter integrated armor cable while tightening the probe body into its mounting bracket, you will shear the internal conductor at the probe head junction. Don’t underestimate the importance of using a dual-wrench technique to lock down the 3/8-24 jam nuts without binding the armored run.
Pay close attention to the unthreaded length choice here. This 2.8-inch unthreaded sleeve is a deliberate mechanical choice—it lets the probe slide deeply into internal machine sleeves without stripping the threads against debris buildup. When attaching the click-lock miniature coaxial connector inside the local driver box, ensure it clicks firmly and is insulated with self-fusing clear heat-shrink tubing to isolate the shield from the metallic junction box frame. Is your target area free of gouges? Verify with the official Bently Nevada installation manual (document 141632) because surface scratches introduce electrical runout that corrupts your vibration signal. Bottom line—proper mechanical gapping prevents probe-tip damage during thermal expansion.
International Shipping & Trade Compliance
Cross-border freight logistics for specialized industrial displacement sensors requires meticulous document management. We declare this assembly worldwide under HS Code 90319000 for customs clarity. Our trade desk provides comprehensive tracking data via expedited air transit pathways (DHL Express, FedEx) to reduce port clearance hold times.
Since this specific option string includes the “02” multi-agency hazardous zone authorization, compliance certificates matching the physical serial plates are checked at our loading dock before cargo release. Typical export operations execute under standard FCA (Free Carrier) or CIP (Carriage and Insurance Paid to) trade protocols.
Frequently Asked Questions
Can I connect this 7200 series probe to a newer 3300 XL Proximitor sensor driver?
No, the 7200 series 8mm probe has a completely different electrical impedance profile than the 3300 XL series. Intermixing them will distort the 200 mV/mil scale factor completely—though your mileage may vary if you are trying to read raw gaps with non-critical display loops (not recommended for trip protection).
What is the minimum target size for an 8mm probe tip?
To achieve the rated 80 mil linear range, the shaft target area must be at least three times the diameter of the probe tip. For an 8mm tip, ensure a flat or gently curved surface area of at least 24 mm in diameter is available.
