Configured for displacement and vibration measurements in machinery protection systems, the Bently Nevada 330703-000-040-10-11-00 (330703 Proximity Probe) provides direct physical/electrical execution. This non-contacting sensor transduces the dynamic distance between the probe tip and the observed conductive target into an electrical signal managed by a 3300 XL Proximitor Sensor. The device measures static shaft position, axial thrust, and dynamic radial vibration without mechanical contact.

Part Number Nomenclature

• 330703: 3300 XL 11 mm Probe, 3/8-24 UNF thread, without armor.

• 000: Unthreaded length option (0.0 in).

• 040: Overall case length option (4.0 in).

• 10: Total length option (1.0 m / 3.3 ft).

• 11: Connector and cable option (Miniature coaxial ClickLoc connector, standard cable).

• 00: Agency approval option (No approvals required).

Technical Parameters

Eddy-Current Scaling and Rotor Dynamics

The 11 mm eddy-current probe system is calibrated for AISI 4140 steel targets to ensure linear voltage scaling across the specified gap range. When the probe tip interacts with a rotating shaft, magnetic field variations generate eddy currents that alter the system impedance. For accurate rotor dynamics analysis, the initial physical installation must balance the gap voltage validation to approximately -10 VDC targets, which represents the midpoint of the linear calibration envelope. Cross-talk suppression is achieved through precise cable length matching, preventing signal interference between adjacent probes measuring orthogonal (X-Y) radial vibration planes.

Package Contents

• 1 330703-000-040-10-11-00 Proximity Probe with integrated 1.0 m coaxial cable

• 2 3/8-24 UNF Hex Jam Nuts

• 1 ClickLoc Connector Protector Cap

• 1 Installation Sheet

Mechanical Installation and Cabling

• Thread Engagement and Torque

• Mount the probe through a clear 3/8-24 threaded hole, verifying a minimum of 5 full threads of engagement to achieve mechanical stability.

• Tighten the locknuts to a maximum torque specification of 10.7 N-m (95 in-lb) to prevent housing deformation.

• Routing Limits and Shielding

• Maintain a minimum bend radius of 25.4 mm (1.0 in) along all sections of the coaxial cable to protect internal conductors.

• Route probe leads inside dedicated, grounded conduit, keeping them isolated from high-voltage AC lines to prevent EMI injection.

Frequently Asked Questions

• What is the standard gap voltage required for calibration?

  The probe must be physically gapped to yield a baseline output of -10 VDC from the connected Proximitor sensor, corresponding to the center of the linear measurement range.

• Can this probe be connected directly to a PLC or DCS analog input card?

  No, this probe requires a 3300 XL Proximitor Sensor to convert its impedance modifications into a modulated -24 VDC voltage output or a 4-20 mA current loop.

• Does this model include integral armor protection for the extension cable?

  No, the 330703-000-040-10-11-00 variant specifies option 000 for unthreaded length and standard non-armored cable configuration.

• What target material is used for the factory calibration?

  The sensor system is calibrated at the factory using AISI 4140 steel; other shaft materials will require recalibration due to altered magnetic properties.

• Is hot-swapping the probe connection permissible while the monitoring system is powered?

  Yes, the coaxial connection to the Proximitor can be broken or made while energized without damaging the sensor components, though it will trigger a channel fault alarm.

• How does moisture affect the coaxial ClickLoc connector junction?

  Moisture contamination introduces parallel resistance that skews the gap readings. Connector silicone boots or environmental sealing tape must be applied in humid environments.

• What is the total allowable system cable length for this probe?

  This probe has a 1.0 m integrated cable and must be paired with a 4.0 m or 8.0 m extension cable to match 5.0 m or 9.0 m system architectures.

• Can I alter the length of the integrated probe cable by cutting it?

  No, altering the physical cable length modifies the system capacitance and tuning, which invalidates the calibration scale factor.