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25 mm Eddy-Current Probe for Differential Expansion Measurement
The Bently Nevada 330851-02-000-080-10-00-00 3300 XL 25 mm proximity probe provides precise non-contact measurement for critical turbomachinery. This probe operates as part of a three-component transducer system with a dedicated 25 mm probe, extension cable, and Proximitor Sensor . It excels at differential expansion (DE) monitoring on mid-size to large steam turbine generators . The system measures the growth difference between the turbine rotor and the machine stator or casing .
Technical Specifications
| Parameter | Specification |
|---|---|
| Model Number | 330851-02-000-080-10-00-00 |
| Brand | Bently Nevada |
| Category | 3300 XL 25 mm Proximity Probe |
| Thread Type | M30 x 2 |
| Case Length | 80 mm |
| Cable Length | 1.0 meter (3.3 feet) |
| Armor | None (unarmored) |
| Scale Factor | 0.787 V/mm (20 mV/mil) |
| Linear Range | 12.7 mm (500 mils) |
| Output Impedance | 50 Ω |
| Minimum Target Size | 61 mm (2.4 in) diameter |
| Probe Tip Material | PEEK (Polyetheretherketone) |
| Probe Case Material | AISI 304 stainless steel |
| Operating Temperature | 200°C continuous, 250°C intermittent |
| Weight | 0.23 kg (8.1 oz) |
| Country of Origin | USA |
Optimized for Differential Expansion Measurement
This probe delivers a scale factor of 0.787 V/mm (20 mV/mil) with a 12.7 mm linear range . This extended range makes the system ideally suited for measuring differential expansion on large steam turbines . The M30 x 2 thread and 80 mm case length provide secure mounting and proper positioning relative to the measurement target .
Construction and Durability
The probe tip uses PEEK material for reliable performance in high-temperature environments . AISI 304 stainless steel construction of the probe case ensures excellent corrosion resistance and mechanical strength . The probe operates continuously at 200°C and withstands intermittent temperatures up to 250°C . Therefore, this probe suits demanding power generation and heavy industrial applications.
System Compatibility and Upgrade Path
This probe replaces all standard 7200 25 mm, 7200 35 mm, and 25 mm DE integral transducer systems, including side and rear exit probes . The Proximitor sensor provides output identical to legacy 7200 and 25 mm DE integral systems . This compatibility allows seamless upgrades without requiring monitor configuration changes . When upgrading, you must replace all three transducer system components: probe, extension cable, and Proximitor sensor .
Applications
Steam turbine differential expansion monitoring
Power generation and heavy industrial machinery
Critical machinery protection and condition monitoring
Replacement for legacy 7200 series and 25 mm DE systems