Configured for integrated vibration measurement in rotating machinery, the Bently Nevada 330881-28-00-070-03-02 (330881 PROXPAC XL Proximity Transducer) provides direct physical signal transduction. This unit combines the probe and signal conditioning circuitry into a single housing, outputting a voltage signal proportional to the distance between the sensor tip and the conductive target for real-time rotor motion monitoring.

Model Configuration Matrix

• 330881: PROXPAC XL Proximity Transducer

• 28: Probe Tip Material and Type

• 00: Unthreaded Length

• 070: Overall Case Length (mm)

• 03: Connector Type

• 02: Agency Approval

Hardware Specifications

Measurement Principles & Signal Fidelity

The PROXPAC XL utilizes eddy-current probe scaling to convert target displacement into a voltage signal. Achieving precision requires strict gap voltage validation; the transducer must be adjusted to a nominal -10 VDC target within the machine's operating range. Effective cross-talk suppression is achieved by observing minimum physical separation distances between adjacent sensors to prevent interference in the 1 MHz carrier frequency. Analysis of rotor dynamics is contingent upon maintaining this linear operation range to prevent waveform clipping.

Component Package Contents

• 1 x 330881-28-00-070-03-02 Transducer Assembly

• 1 x Integrated connector assembly

• 1 x Technical installation instruction packet

Field Installation & Grounding

• Mechanical Mounting: Use a non-conductive mounting bracket to ensure electrical isolation of the transducer case from the machine housing.

• Grounding Scheme: Maintain a single-point ground connection for the signal common to eliminate ground loops.

• Conduit Routing: Shielded conduit is required for all cable runs to mitigate electromagnetic noise.

• Gap Setting: Use a feeler gauge to establish the initial installation gap before fine-tuning via the -10 VDC voltage output.

• Torque Verification: Apply manufacturer-recommended torque to the mounting jam nut to prevent vibration-induced mechanical loosening.

Technical Inquiry Index

• Q: What is the primary difference between PROXPAC and standard Proximitor systems?

  A: The PROXPAC XL integrates the probe and Proximitor electronics into a single assembly, reducing external cabling requirements.

• Q: Can the transducer be submerged in process fluid?

  A: The transducer is designed for installation in lube oil environments; however, it must not be submerged in pressurized process gas or liquid.

• Q: Is the system compatible with 24 VDC power supplies?

  A: It requires a negative supply (-24 VDC). Positive supply connection will result in immediate circuit failure.

• Q: How do I test the transducer output?

  A: Monitor the output voltage using a high-impedance digital multimeter while adjusting the gap to the metallic target.

• Q: Is there a limit to the cable length?

  A: The integrated design has a fixed length; do not modify or extend the integral cable as this impacts system frequency response.

• Q: Does the transducer require special calibration for different steels?

  A: The device is factory-calibrated for 4140 steel; other materials may exhibit different permeability and require scaling factor adjustments.

• Q: What indicates an over-range condition?

  A: Output voltage dropping below -1 VDC or exceeding -20 VDC typically indicates the target is outside the linear measurement range.

• Q: Are the internal electronics field-repairable?

  A: No, the transducer is a hermetically sealed unit; any internal component failure requires replacement of the entire transducer assembly.