Product Overview

The Bently Nevada 330881-28-04-145-03-02 PROXPAC XL represents a sophisticated evolution in machinery protection, combining an 8 mm eddy current probe and a Proximitor sensor into a single, robust housing. Engineered specifically for critical rotating assets—such as steam turbines, centrifugal compressors, and large pumps—this transducer provides high-precision, non-contact measurements of radial vibration and axial thrust.

By integrating the sensor directly into the housing cover, this assembly eliminates the traditional signal loss risks associated with extension cables. This self-contained architecture simplifies field wiring and reduces the overall footprint of the Turbine Supervisory Instrumentation (TSI) system. Its high-performance Polyphenylene Sulfide (PPS) construction ensures the unit thrives in the presence of chemical exposure and electromagnetic interference, delivering the sub-micron resolution necessary for early fault detection in high-speed machinery.

Technical Configuration Details

The 330881-28-04-145-03-02 utilizes a modular part-numbering system to match specific mechanical requirements of the machine train:

Probe and Seal Option (-28)

This specifies the integration of a 3300 XL 8 mm probe with multi-approval certifications (including ATEX/IECEx for hazardous areas) and high-pressure Viton seals to prevent process fluid leakage.

Standoff Length (-04)

The 40 mm standoff provides the necessary clearance between the mounting port and the external housing, allowing for easier adjustment and tool access during commissioning.

Probe Penetration (-145)

A 145 mm penetration depth ensures the probe tip reaches the target shaft surface through thick machine casings or insulation layers, providing a stable measurement window.

Fitting Option (-03)

This configuration includes one M20 fitting and two plugs, optimizing the housing for standard metric conduit systems while maintaining a sealed internal environment.

Mounting Thread (-02)

The 3/4-14 NPT mounting thread provides a standardized, high-strength mechanical connection to the machine's bearing housing or bracketry.

Technical Specifications

Engineering Installation & Maintenance Guide

Gap Voltage Calibration

During installation, engineers must set the mechanical gap between the probe tip and the shaft target. For the 3300 XL 8 mm system, the standard "middle of the linear range" is achieved when the DC output voltage is approximately -10.0 VDC. Use a calibrated digital multimeter to verify this voltage before tightening the locknuts.

Housing Grounding and Shielding

The PPS housing contains conductive fibers to dissipate static. Ensure the field wiring shield is grounded at the monitor end only (e.g., the 3500 rack). Avoid "daisy-chaining" shields to prevent ground loops that can introduce noise into the vibration signal.

Cable Management

Maintain a minimum bend radius of 25.4 mm (1 inch) for the internal wiring. Even though this unit eliminates the external extension cable, internal lead wires must be secured to prevent fatigue caused by high-frequency machine vibration.

Engineering Advantages

• Self-Contained Efficiency: The PROXPAC XL eliminates the need for separate Proximitor housings on the machine skid, reducing installation labor and hardware costs.

• EMI Immunity: The advanced thermoplastic construction provides superior shielding against electrical noise compared to traditional aluminum housings, ensuring signal integrity in "dirty" electrical environments.

• Field Adjustability: The design allows for probe depth adjustment without disassembling the machine, facilitating rapid recalibration during scheduled outages.

• Total TSI Integration: Fully compatible with Bently Nevada 3500 and 3300 monitoring racks, ensuring seamless data flow for predictive maintenance programs.

Global Logistics & Delivery

We maintain high-velocity stock of the 330881-28-04-145-03-02 to minimize your facility's downtime.

• Delivery Time: 3-5 business days following payment confirmation.

• Shipping Partners: Express delivery via DHL, FEDEX, or UPS.

• Packaging: Shipped in Anti-Static (ESD) protective packaging within a heavy-duty reinforced carton to ensure industrial-grade safety during transit.

Technical FAQs

Q1: How do I verify the probe is functioning correctly before start-up?

A1: Perform a static calibration check. Connect a -24VDC power supply and move a target material (4140 steel) toward the probe tip. Measure the output voltage; it should change linearly at 200 mV per mil of movement.

Q2: Can the 330881-28-04-145-03-02 replace an older 7200 series Proximity system?

A2: Yes, the 3300 XL series is the functional successor to the 7200 series. However, since this is a self-contained unit, you will need to re-route your field wiring directly to this housing rather than to a remote Proximitor.

Q3: What is the benefit of the PPS housing over traditional stainless steel?

A3: PPS offers exceptional chemical resistance to synthetic lubes and acids that can corrode metals. Furthermore, the conductive fibers in the PPS prevent the buildup of electrostatic charges, which is a critical safety feature in hazardous zones.

Q4: Does this module require a separate extension cable?

A4: No. One of the primary advantages of the PROXPAC XL is that the probe connects directly to the integrated Proximitor sensor inside the housing, eliminating the need for a 5m or 9m extension cable.