Engineered explicitly for hydrodynamic bearings and high-speed turbomachinery constrained by severe space limitations, the Bently Nevada 330904-00-12-05-02-05 (330904-00-12-05-02-05 3300 NSv Proximity Probes) delivers precise non-contact displacement tracking where standard 8 mm sensor geometries cannot physically fit.

Configuration and Designation Matrix

• Base Design: 330904 (3300 NSv Armored Probe Assembly)
• Unthreaded Body Length: 00 (0 mm unthreaded portion beneath head)
• Case Length Specification: 12 (120 mm overall threaded barrel length)
• Integral Cable Length: 05 (0.5 meter / 20 in lead length)
• Termination Hardware: 02 (Miniature coaxial ClickLoc connector with standard cable)
• Hazardous Area Certifications: 05 (Multiple Approvals including CSA, ATEX, IECEx)
• System Platform: Bently Nevada 3300 XL NSv

Physical and Electrical Parameters

Field Tuning and Mechanical Dynamics

Operating small-bore machinery requires strict validation of the static gap voltage to ensure linear measurement across the restricted 1.5 mm span. Maintenance engineers must adjust the probe mounting depth until the voltmeter at the Proximitor output terminal reads -10 VDC, maintaining an active window between -8 VDC and -12 VDC. Because armored stainless steel cabling provides mechanical protection against harsh compressor environments, technicians must still ensure proper shield grounding and maintain adequate physical separation from high-frequency variable-frequency drive lines to prevent electromagnetic cross-talk.

Bill of Materials Included

• 1 x 330904 NSv Armored Probe Tip with M8x1 Threaded Body
• 1 x Integral 0.5-meter Coaxial Cable with ClickLoc Connector
• 1 x Stainless Steel Protective Armor Hose (Factory Installed)
• 1 x Factory Calibration and Conformance Documentation

Mechanical Installation and Alignment Rules

• Hole Preparation: Machine and tap the equipment casing for an M8x1 thread, ensuring the mounting face is machined completely flat and square to the rotor shaft.
• Torque Limits: Tighten the probe body using a calibrated wrench to establish a firm mechanical lock, avoiding excessive torque that could distort the internal PPS plastic tip.
• Initial Gap Setting: Set the cold static gap distance to 1.0 mm (40 mils) using a feeler gauge or depth micrometer before locking jam nuts in place.
• Clearance Margins: Ensure a minimum counterbore diameter of 13 mm (0.5 in) around the probe tip to prevent edge-effect distortion of the high-frequency electromagnetic field.

Technical FAQ

• Why does the NSv series use a smaller linear range than standard 8 mm probes?

  The specialized coil geometry and field shaping are optimized for small targets and tight counterbores, resulting in a condensed 1.5 mm linear operating range.

• Can this probe operate directly with a standard 8 mm Proximitor sensor?

  No, NSv probes require a matched 3300 XL NSv Proximitor sensor calibrated specifically to the unique electrical characteristics of the NSv coil design.

• What is the primary purpose of the stainless steel armor?

  The armor provides robust mechanical shielding against physical abrasion, metal chips, and harsh fluid contact inside congested compressor housings.

• Is it acceptable to shorten or splice the integral 0.5-meter cable?

  No, altering the cable length changes total circuit capacitance, which invalidates factory calibration and distorts vibration amplitude output.

• How close can two NSv probes be mounted in an X-Y radial configuration?

  Maintain a minimum center-to-center tip separation of 23 mm (0.9 in) to prevent high-frequency carrier signal interference between adjacent channels.

• What causes sudden shifts in the steady-state gap voltage?

  Thermal expansion of machine casings, shifting journal positions, or loose mounting clamps typically introduce observable DC voltage drifts.

• Does this probe support live hot-swapping during plant operation?

  Disconnecting sensor circuits on active machinery can introduce electrical noise spikes that risk triggering false protection system trips.

• What is the maximum distance allowed between the Proximitor and the monitor?

  The signal loop can extend up to 305 meters (1,000 feet) using three-conductor shielded triad cable connected to the monitor rack.