Configured for protective containment and external transducer adjustment in rotating machinery monitoring systems, the Bently Nevada 31000-28-05-00-056-01-02 (31000 Proximity Probe Housing Assemblies) provides direct physical/electrical execution.

Suffix Selection Matrix

The individual configuration elements of the 31000-28-05-00-056-01-02 housing assembly are defined by the following suffix parameters:

• 31000: Base model designation for standard proximity probe housing assembly.
• -28: Factory-installed 3300 XL 8 mm proximity probe with multiple hazardous area approvals.
• -05: Integrated probe cable length of 0.5 meter (20 inches).
• -00: No standoff adapter included.
• -056: Probe penetration depth of 5.6 inches (142.24 mm).
• -01: Conduit fittings option consisting of one 3/4-14 NPT fitting and two plugs.
• -02: Main housing mounting thread size of 3/4-14 NPT.

Mechanical & Physical Parameters

Gap Voltage Validation and Rotor Dynamics Integration

The 31000-28-05-00-056-01-02 assembly integrates a 3300 XL 8 mm probe inside a robust environmental dome, providing continuous measurement data for rotor dynamics monitoring. The target displacement is captured via high-frequency eddy-current probe scaling, outputting an analog signal to a companion 3300 XL Proximitor Sensor.

For proper integration into machinery protection systems (such as the Bently Nevada 3500 series), the field engineer must execute a physical gap voltage validation. The nominal target is set to -10 VDC, corresponding to the electrical midpoint of the transducer's linear performance curve. This design ensures that static axial movement or dynamic radial vibration remains centered within the calibrated -2 VDC to -18 VDC operating window.

Shipping Checklist

• 1 x Bently Nevada 31000-28-05-00-056-01-02 housing assembly with pre-installed 3300 XL probe
• 1 x 3/4-14 NPT conduit fitting
• 2 x Conduit port plugs
• 1 x O-ring seal kit

Field Installation Instructions

• Threading and Seal Engagement

  Apply a compatible thread sealant to the 3/4-14 NPT mounting threads. Thread the housing assembly into the machine casing hand-tight, then wrench-tighten to ensure a leak-tight seal against internal machine pressure.

• Physical Gap Calibration

  Remove the external PPS dome to expose the probe adjustment sleeves. Connect a digital voltmeter to the Proximitor terminal loop and rotate the internal adjustment sleeve until the DC gap voltage registers -10 VDC.

• Locking the Adjustment Sleeve

  Once calibration is achieved, lock the probe position using the integrated mechanical locknut. Tighten to standard specification to prevent drift caused by high-frequency vibration within the machine case.

• Conduit and Cable Routing

  Lead the 0.5 m probe cable out through the 3/4-14 NPT conduit fitting. Ensure all unused conduit ports on the housing are sealed using the two provided stainless steel plugs to block moisture ingress.

Transducer Housing FAQ

• Can the internal probe be replaced without shutting down the machinery?

  Yes. The housing is designed to allow external access so that the proximity probe and its cable can be uninstalled or adjusted while the machine remains in operation.

• What is the purpose of the PPS thermoplastic dome on the 31000 housing?

  The polyphenylene sulfide (PPS) dome provides high-strength impact protection and resistance to corrosive chemical sprays, protecting the electrical connections inside.

• Why does this specific configuration omit a standoff adapter?

  The "-00" option is chosen when the standard 5.6-inch probe penetration depth aligns directly with the machine casing thickness, rendering a standoff spacer unnecessary.

• Does this 5.6-inch probe penetration depth require an internal support sleeve?

  No. Sleeve supports are only required for penetrations exceeding 12 inches (305 mm) to mitigate the risk of mechanical resonance and probe stem bending.

• What happens to the signal output if the target material is not AISI 4140 steel?

  The scale factor will deviate from the nominal 200 mV/mil. The Proximitor must be recalibrated to prevent inaccurate vibration and position amplitude readings.

• Is the housing gas-tight when properly installed on the machine case?

  Yes. The housing features standard O-ring seals and NPT thread engagement, which successfully contain oil mist and gases up to normal machinery casing pressures.

• What is the primary difference between the 31000 and 32000 housing series?

  The 31000 series operates from -51 to +177 deg C, whereas the 32000 series has an extended range of -62 to +204 deg C and uses Inconel 718 components.

• How should the conduit connections be sealed to maintain the explosion-proof rating?

  Thread the certified 3/4-14 NPT fitting tightly and use approved explosion-proof sealing compound at the conduit entry to prevent gas migration.