Bently Nevada 21000-28-05-00-024-03-02 Retrofit-Ready Proximity Probe for 3300 XL Control Systems
The Bently Nevada 21000-28-05-00-024-03-02 is a precision proximity probe housing assembly engineered for seamless integration into Bently Nevada 3300 XL Series vibration monitoring systems. Designed to serve as a direct retrofit replacement for legacy and discontinued proximity probe configurations, this component enables industrial facilities to modernize aging condition monitoring infrastructure without requiring full system overhauls. Whether you are upgrading a turbine protection rack, replacing a worn probe in a compressor train, or restoring a dormant monitoring loop, the 21000-28-05-00-024-03-02 delivers the dimensional accuracy, signal integrity, and system compatibility that critical rotating machinery demands.
This probe housing assembly is fully compatible with the Bently Nevada 3300 XL proximitor/seismic monitor platform, including the 3300/16 and 3300/20 monitor modules. It interfaces directly with standard Bently Nevada extension cables and proximitor sensors such as the 3300 XL 8mm Proximitor Sensor, maintaining the 200 mV/mil output sensitivity required by the monitoring system’s signal conditioning chain. Facilities running legacy 3300 Series (non-XL) hardware should verify proximitor compatibility and gap voltage calibration requirements before installation.
Upgrade Compatibility Table
| Parameter | Details |
|---|---|
| SKU / Part Number | 21000-28-05-00-024-03-02 |
| Compatible Platform | Bently Nevada 3300 XL Series |
| Probe Type | Proximity Probe Housing Assembly |
| Output Sensitivity | 200 mV/mil (standard 3300 XL) |
| Thread / Mounting | Per OEM specification; verify against existing bracket |
| Extension Cable Interface | Compatible with standard 3300 XL extension cables |
| Communication / Signal | Eddy-current analog signal; no protocol conversion required |
| Replacement Recommendation | Direct drop-in for discontinued 21000-series probe housings |
| Commissioning Note | Gap voltage calibration required post-installation (typically −10 VDC ± 0.5 V) |
| Warranty | 12 months from date of shipment |
Retrofit Planning for Existing Automation Systems
Retrofitting a Bently Nevada proximity probe in an operating plant requires careful coordination across multiple system layers. Before removing the existing probe, technicians should document the current gap voltage reading at the 3300 XL proximitor output and record the baseline vibration amplitude and phase reference values from the System 1 condition monitoring software. This baseline data is essential for post-installation verification and ensures that the replacement probe is performing within the expected dynamic range of the monitoring loop.
The probe housing assembly connects to the proximitor via a field-replaceable 3300 XL extension cable, typically available in 5-meter or 9-meter lengths. When replacing the probe housing, inspect the extension cable connector for corrosion or mechanical damage — a degraded cable can introduce signal noise that mimics shaft vibration anomalies. If the extension cable is also due for replacement, sourcing it alongside the 21000-28-05-00-024-03-02 housing minimizes repeat downtime.
For installations where the 3300/16 monitor module or 3300/20 monitor module is approaching end-of-life, this retrofit is an ideal entry point for a broader rack modernization. The 3300 XL rack accepts standard 3300 XL power supply modules and can be expanded with additional I/O channels using compatible 3300 XL I/O modules. Facilities planning a full migration to the Bently Nevada 3500 Series platform should note that the 3500 system uses a different proximitor architecture and signal scaling — a direct probe swap between platforms is not supported without reconfiguration of the 3500/42M or 3500/40M monitor modules and corresponding updates to System 1 channel configuration.
In control cabinets where the 3300 XL rack shares enclosure space with a DCS or safety system, verify that the probe cable routing maintains adequate separation from high-voltage power conductors. Induced electrical noise from variable frequency drives or transformer primaries can corrupt the eddy-current signal and trigger false high-vibration trips. Shielded cable trays and proper grounding of the proximitor chassis are standard mitigation measures during retrofit commissioning.
For plants operating Bently Nevada TK-3 or TK-4 proximity transducer systems alongside the 3300 XL platform, ensure that the replacement probe housing thread form and tip geometry are matched to the existing bearing housing bore. Mismatched probe geometry will produce incorrect gap calibration and may prevent the system from achieving the required linear measurement range.
Downtime Control During System Migration
Minimizing unplanned downtime during a proximity probe replacement begins with pre-staging all replacement components before the maintenance window opens. For the 21000-28-05-00-024-03-02, this means having the probe housing, extension cable, and any required mounting hardware on-site and verified against the work order BOM before the machine is taken offline. A pre-tested spare — gap-calibrated on a bench fixture using a representative target material — can reduce in-field commissioning time from hours to minutes.
During the swap, the original program logic in the connected PLC or DCS does not require modification, as the 3300 XL monitor outputs a standard 4–20 mA or relay contact signal to the control system. However, if the plant’s DCS historian or HMI faceplate displays raw gap voltage or proximity counts, operators should be briefed on expected transient readings during the re-gapping procedure to avoid unnecessary alarm acknowledgment or manual overrides.
After installation, perform a static gap check with the shaft stationary, confirm the proximitor output voltage is within the linear range, and then bring the machine to operating speed under observation. Compare the vibration amplitude and phase readings against the pre-outage baseline. If the values are within ±5% of baseline, the retrofit is complete. Any significant deviation warrants a re-inspection of probe tip clearance, extension cable continuity, and proximitor power supply voltage from the 3300 XL power supply module.
All units ship with a 12-month warranty covering manufacturing defects and signal performance. Pre-shipment functional testing is performed on every unit to verify dimensional tolerances and electrical continuity before dispatch.
Retrofit Support FAQ
Q: Is the 21000-28-05-00-024-03-02 a direct replacement for my existing 3300 XL proximity probe housing?
A: Yes, this part number is a direct retrofit replacement for the corresponding discontinued Bently Nevada 21000-series proximity probe housing. It maintains the same thread form, tip geometry, and electrical interface required by the 3300 XL proximitor system. Verify your existing mounting bracket dimensions and target material before installation.
Q: What gap voltage should I set after installing the replacement probe?
A: The standard gap voltage for 3300 XL proximity systems is −10 VDC ± 0.5 V at the nominal air gap specified for your bearing clearance. Refer to the Bently Nevada 3300 XL installation manual for your specific probe length and target material combination. Always perform gap calibration with the shaft stationary before startup.
Q: Does this probe require any wiring changes at the 3300 XL monitor module?
A: No wiring changes are required at the monitor module terminal block. The 21000-28-05-00-024-03-02 uses the same coaxial connector interface as the original probe housing and connects to the existing extension cable without modification. Inspect the extension cable and connector for wear before reuse.
Q: What warranty and pre-shipment testing is included?
A: Every unit undergoes functional testing prior to shipment, including dimensional verification and electrical continuity checks. A 12-month warranty from the date of shipment covers manufacturing defects and signal performance. Contact our team for warranty claims or technical support during commissioning.
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