Description
The Bently Nevada 330851-02-000-080-90-01-05 is a high-accuracy, eddy-current proximity probe belonging to the 3300 XL 25 mm Transducer System. Delivering an Average Scale Factor (ASF) of 0.787 V/mm (200 mV/mil), this system provides a linear measurement range of 12.7 mm (500 mils). It is used primarily for monitoring Differential Expansion (DE) on utility steam turbine generators, tracking the relative growth differential between the machine stator and the turbine rotor.
Commercial Availability & Terms
- Condition: New Original (Factory Sealed)
- Warranty: 12 months from delivery date
- Availability: In stock
- Lead Time: Ships within 1–2 business days via global air express (DHL, FedEx, UPS)
- Pricing Note: Price subject to market conditions; contact us for a firm quote.
Part Number Breakdown & Configuration
The complete alphanumeric part number defines specific mechanical dimensions, casing options, cable lengths, and global regulatory approvals:
| Segment | Option Code | Parameter Meaning | Exact Value Spec |
| Product Base | 330851 |
Product Family Series | 3300 XL 25 mm Proximity Probe |
| Case Type | 02 |
Case Threading Type | M30x2 Threaded Case |
| Unthreaded Length | 000 |
Unthreaded Housing Length | 0 mm (Fully threaded) |
| Overall Case Length | 080 |
Complete Shell Depth | 80 mm Case Length |
| Total Length | 90 |
Total Cable Configuration | 9.0 meters (29.5 feet) |
| Armor Option | 01 |
Mechanical Outer Protection | High-flexibility AISI 302 stainless steel armor |
| Agency Approval | 05 |
Explosion/Safety Certification | Multiple Approvals (ATEX, IECEx, CSA Class I Div 1/2) |
Field Integration & Calibration Constraints
In field deployments of 3300 XL 25 mm systems, the combination of total cable length and matched components governs calibration stability.
System Matching Limits
The total electrical length of the probe plus any intermediate extension cable must match the input calibration parameter of the target 3300 XL 25 mm Proximitor Sensor (Model 330850). Because this probe features the 90 option code (9.0 meters total integrated length), it must be connected directly to a 9.0 meter Proximitor Sensor without an extension cable. Adding an intermediate extension cable to a 9-meter probe shifts the system’s operational capacitance, causing major calibration drift and output clamping.
Target Material Requirements
System calibration and accuracy specifications apply explicitly when measuring against a Bently Nevada AISI 4140 steel target with a minimum target diameter of 61 mm (2.4 in).
- Target Size: Targets smaller than 61 mm fail to contain the magnetic field generated by the larger 25 mm probe tip, distorting the output voltage curves.
- Alternative MOCs: If the shaft or target collar uses an alternate material composition (e.g., 18CrNiMo7-6 or 4340), the system must be recalibrated at the factory or custom-gapped to account for target conductivity changes.
Installation Warning: Do not exceed a torque rating of 68 N\cdotm (50 ft\cdotlb) when anchoring the M30 threaded housing into the machine bracketry. Over-torquing will deform the internal coils or cause micro-fractures in the TipLoc molding bonding layer, causing a catastrophic sensor failure during high-vibration machine execution.
Frequently Asked Questions
What is the exact function of the “01” Armor option?
The 01 option equips the probe cable with a protective, flexible sheath of AISI 302 stainless steel armor. This outer armor shields the internal coax wire from sharp edges, flying debris inside the bearing housing, and mechanical crushing during installation or machine maintenance.
Can this 25 mm probe be routed directly to a standard 3300 XL 8 mm Proximitor?
No. The 25 mm probe tip generates a significantly larger magnetic field than an 8 mm probe. Interfacing this module with a standard 8 mm Proximitor sensor causes an immediate transducer mismatch fault and clips the voltage loop output to its maximum rail. It must only be paired with a 3300 XL 25 mm Proximitor Sensor (Series 330850).
What maintenance steps are recommended for the integrated cable connectors?
Keep the gold-plated miniature coaxial connectors completely free of oil, moisture, and debris. During installation inside the turbine carriage, clean the connections with electronics contact cleaner, finger-tighten the coupling, and deploy a Bently Nevada Connector Protector Kit (such as the CP95 or 161849) to seal the interface from aggressive lube oil environments
