Description
Meta Description
Evaluate the technical specifications, physical thread footprint, and critical spares management guidelines for the Bently Nevada 330707-00-20-10-02-00 11mm eddy-current proximity probe.
Technical Evaluation and Inventory Strategy
The Bently Nevada 330707-00-20-10-02-00 belongs to the 3300 XL 11 mm proximity transducer product line. Unlike standard 8 mm options, this 11 mm variant offers an extended linear measurement range of up to 4.0 mm (160 mils) with a normalized scale factor of 3.94 V/mm (100 mV/mil). It is engineered for industrial turbomachinery where high thermal expansion or structural movement requires an expanded tracking window—such as large steam turbines, high-capacity centrifugal compressors, and generator rotors.
Core Performance Parameters
| Parameter Option | Value | Field Application Impact |
| Unthreaded Length (-00) | 0.0 inches | The probe case is fully threaded up to the transitions of the tip encapsulation. |
| Overall Case Length (-20) | 2.0 inches | Fits shallow bearing housing bores and localized bracket standoffs. |
| Total System Length (-10) | 1.0 meter (3.3 feet) | Must be paired exclusively with an 11 mm 4.0m or 8.0m extension cable to complete standard system balancing. |
| Connector Option (-02) | ClickLoc Miniature Coaxial, Standard Cable | Gold-plated, unarmored triaxial pigtail configuration utilizing finger-locking connection faces. |
| Agency Approval (-00) | Not required | Dedicated to general-purpose or unclassified industrial plant zones. |
| Thread Profile | 5/8-18 UNF-2A | Heavy-gauge physical threads designed to handle harsh mechanical stress profiles. |
Field Operations and Risk Assessment
Why does an 11 mm probe tip change your mechanical alignment strategy? Because the tip diameter is significantly larger than standard 8 mm variants, the 330707-00-20-10-02-00 requires a larger target area on the observed shaft (minimum 30.5 mm or 1.2 inches diameter flat surface). Well, technically the mid-point calibration gap sits at roughly 2.5 mm (100 mils) corresponding to a target output of -10.0 V DC from the Proximitor sensor, but if your maintenance team fails to account for the larger field-of-view, adjacent housing features can cause severe side-view interference, distorting the true vibration signal.
[Larger Target Shaft: >30.5mm] <── Midpoint Gap: 2.5mm ──> [11mm PPS Tip][5/8-18 Case] ──> [1.0m Lead] This specific layout changes your maintenance risk profile. The unarmored standard cable (-02) lacks the protective outer flexible conduit of armored models, making the pigtail vulnerable to sharp sheet-metal edges during high-intensity turbine turnarounds.
Spares Management and Sourcing Matrix
Because 11 mm probes are highly specialized and often feature extended factory lead times (ranging from 6 to 12 weeks), proactive warehousing is required to prevent a channel fault from stalling a machine restart.
- Stocking Recommendation: Maintain a strict 1-unit baseline spare for every 4 active 11 mm points in the plant profile. Do not attempt to use 8 mm spares as temporary fixes; the mechanical sizing, electronic linear range, and output scale factors are fundamentally mismatched.
- TCO and Tool Handling: Never store replacement probes loose in parts bins. The polyphenylene sulfide (PPS) tip material can crack if struck by dropped hand tools. Retain all backup stock within factory-sealed bags to maintain the integrity of the integrated ClickLoc locking threads.
- Surplus Sourcing and Integrity Mapping: When utilizing independent supply chains to bypass long factory distribution queues, inspect the copper coil beneath the tip encapsulation. Any surface pitting or deep scratches from a previous partial install will degrade the eddy-current balance, making the card unreliable for API 670 safety loops.
Limitations and “Not Recommended For” Scenarios
Do not deploy the 330707-00-20-10-02-00 on small-diameter shafts measuring under 152 mm (6.0 inches). Running an 11 mm probe on a narrow shaft curves the target area away too rapidly, invalidating the calibration and ruining measurement linearity. Additionally, this unarmored configuration is completely unsuited for high-pressure fluid immersion zones or direct acidic washdowns—for those configurations, route the raw cable through liquid-tight metallic conduit or upgrade to an armored variant.
Quick Conclusions
- Criticality: High (Class A). Core non-contact sensor driving safety-instrumented turbomachinery channels.
- Stocking Level: 1-2 functional spares on-site per major generation or compression train running 11 mm probes.
- Lifecycle Status: Active product catalog; fully supported within the Bently Nevada ecosystem.
- Key Vulnerability: Side-view interference from small targets and cable jacket shearing.
FAQ
Can I connect this 11 mm probe directly to an 8 mm Proximitor sensor module?
No. The 11 mm probe has a larger internal coil footprint with different electrical impedance profiles compared to an 8 mm probe. It must be paired with a dedicated 3300 XL 11 mm Proximitor Sensor to ensure the system scales correctly to the proper 3.94 V/mm (100 mV/mil) output.
What is the specific function of the FluidLoc option mentioned in the series technical brief?
While this specific SKU features standard insulation, the 3300 XL series can be ordered with FluidLoc cables. That variant includes internal sealing that prevents lubricating oil or process gases from leaking out of the machine housing through the interior core of the coaxial cable.
How do I address a “Sensor Fault” light on the 3500 rack when using this probe?
A fault light typically indicates an electrical open circuit or a dead short along the sensor line. Use a digital multimeter to check the center pin and outer shield continuity across the ClickLoc connection—resistance on a disconnected probe should read low, whereas a direct short to the machine casing indicates damaged internal insulation.
