Configured for high-temperature differential expansion and shaft position surveillance within steam turbine platforms, the Bently Nevada 330851-02-000-060-10-01-05, also cataloged as the 330851 3300 XL 25 mm Proximity Probe, operates as a dedicated hardware component for eddy-current displacement measurement across machinery protection systems.

Suffix Breakdown & Model Matrix

• Base Model Number: 330851 (3300 XL 25 mm Proximity Probe Assembly)
• Probe Case Type Option (-02): M30x2 thread configuration with 0 mm unthreaded length
• Overall Case Length Option (-000): 0.6 in case length parameter
• Total Length Option (-10): 1.0 metre (3.3 feet) cable length
• Armor and Approval Options (-01-05): Includes stainless steel armor and multiple hazardous area approvals

Hardware Specifications

Rotor Dynamics and Transducer Measurement Mechanics

• Eddy-Current Probe Scaling: The 25 mm transducer utilizes high-frequency radio frequency circuitry to excite the probe tip coil, producing a linear voltage output proportional to the wide gap distance between the probe face and large turbine shaft targets.
• Gap Voltage Validation: Field technicians must verify that the initial static operating point achieves exact voltage parameters using a calibrated multimeter during mechanical alignment to ensure linear response across the extended dynamic range.
• Cross-Talk Suppression: Spatial isolation and high-frequency modulation design prevent electromagnetic interference when multiple large-format proximity probes are installed adjacently on complex turbine casings.
• Rotor Dynamics Monitoring: Translates large-scale thermal growth, differential expansion, and axial rotor movement into high-fidelity electrical inputs for continuous machinery protection monitors.

Ordering Info

• 1 x 330851-02-000-060-10-01-05 330851 Proximity Probe Assembly
• 1 x Matching 3300 XL 25 mm Extension Cable with SST Armor
• 1 x Connector Protector and Installation Tool Kit

Mechanical Installation Guidelines

• Target Material Verification: Ensure the monitored target consists of flat AISI 4140 steel with a minimum diameter of 61 mm (2.4 in) to maintain linear scaling accuracy.
• Sliding Bracket Usage: Utilize a dedicated sliding bracket during commissioning to physically move the probe, simulating shaft motion and verifying system calibration.
• Locknut Torque and Safety Wire: Tighten the M30x2 threaded case locknut securely, utilizing pre-drilled safety wire holes to prevent loosening under severe turbine vibration.
• Moisture Protection Routing: Route the FluidLoc cable carefully through tight clearances using the removable ClickLoc connector collar while maintaining front and rear seal integrity against steam environment moisture.

Frequently Asked Questions

• What is the total nominal weight of the 330851 probe assembly?

  The unit weighs approximately 0.34 kg.

• What are the physical shipping package dimensions?

  The shipping container measures 2.8 x 2.8 x 115 cm.

• What linear measurement range does the 25 mm transducer provide?

  It delivers an extended linear measurement range of 12.7 mm (500 mils).

• What is the nominal scale factor for this 25 mm probe system?

  The incremental scale factor is calibrated to 0.787 V/mm, equivalent to 20 mV/mil.

• What maximum operating temperature can the probe withstand continuously?

  The probe is rated for continuous operation in temperatures up to 200 deg C (392 deg F).

• What intermittent temperature limit is supported by the sensor tip?

  It can withstand intermittent high temperatures up to 250 deg C (482 deg F).

• What primary machinery parameter does this transducer monitor?

  It monitors differential expansion (DE) on mid-size to large steam turbine generators caused by differential thermal growth.

• What shaft target dimensions are required for optimal accuracy?

  The system requires a flat AISI 4140 steel target with a minimum diameter of 61 mm (2.4 in).