Product Overview

The Bently Nevada 128987-130-00-00 3300 XL 8 mm Proximity Probe establishes critical, non-contact mechanical tracking within high-reliability machinery protection systems. This heavy-duty reverse-mount eddy current sensor continuously tracks shaft radial vibration, dynamic position displacement, and axial thrust clearance variations across critical high-speed rotating components.

Reliability managers deploy this specific reverse-mount probe architecture within complex Turbine Supervisory Instrumentation (TSI) installations where exterior mounting space constraints prevent the use of standard front-mount probes. It provides continuous tracking on high-capital plant assets, including industrial steam turbines, heavy-duty centrifugal compressors, and critical process pumps. The internal sensor geometry transmits an ultra-responsive analog raw signal directly to centralized monitoring racks. This precise telemetry feeds automated emergency shutdown loops and distributed DCS interlocks, allowing the system to execute critical machinery trips instantly before catastrophic bearing or structural breakdown occurs.

Part Number Option String Interpretation

128987 [3300 XL 8 mm Reverse Mount Base Configuration]

Designates the product profile as an 8 mm tip diameter eddy current proximity probe assembly utilizing a reverse-mount housing thread design, optimized for installation inside specialized internal brackets or sleeves.

-130 [Total Electrical Length Option]

Specifies a total physical cable length option of 13.0 meters (approximately 42.7 feet) measured from the probe tip face to the distal terminal end, removing the need for a separate intermediate extension cable in long-distance runs.

-00 [Connector Protection Profile]

Indicates the inclusion of standard miniature coaxial ClickLoc connectors without an external connector protector sleeve, simplifying direct insertion through tight field conduit tracks.

-00 [Hazardous Area Agency Certification]

Supplied with standard non-hazardous area industrial operational approvals, calibrated strictly for high-performance plant locations requiring standard mechanical tracking compliance.

Transducer Core Performance Layout

Site Positioning & Internal Alignment Protocols

Field instrumentation specialists must establish the precise mechanical gap clearance using an accurate digital voltmeter during physical deployment due to the specialized nature of the reverse-mount housing. Thread the 128987-130-00-00 probe body into its internal machine bracket while monitoring the raw DC gap voltage at the corresponding 3300 XL Proximitor sensor test terminals. Rotate the probe until the meter displays approximately -10.0 VDC, representing the mathematical center of the calibrated 2.0 mm linear operational field.

Maintain a strict minimum bend radius of 25.4 mm (1.0 inch) along the unarmored 13-meter coaxial line to prevent internal core fatigue or changes in high-frequency impedance properties. Route this long sensor line inside isolated, grounded steel conduits to prevent heavy plant electromagnetic interference (EMI) from distorting the sensitive analog vibration signal. Secure the probe locknut tightly to prevent the sensor body from backing out under high-velocity machine vibration cycles.

Structural Survivability & Infrastructure Integration

The advanced engineering of the 3300 XL reverse-mount probe utilizes a premium polyphenylene sulfide (PPS) composite tip material, injection-molded over the internal wire coil to create an airtight seal. This structural barrier prevents degradation or moisture absorption when the sensor body remains constantly exposed to hot synthetic bearing lubricants, corrosive gaseous environments, or high-pressure steam within internal bearing housings.

The low-loss 13-meter coaxial line routes the unattenuated analog displacement telemetry directly to the input channels of a centralized Bently Nevada 3500/42M machinery protection rack. The rack system transmits these real-time dynamic profiles to a plant-wide Honeywell Experion PKS or Siemens S7 PLC framework via dedicated analog loops or automated Modbus TCP channels. This multi-layered layout provides the control room with simultaneous access to split-second safety interlocks and deep predictive machine health trending.

Commercial Packing Inventory

The factory-sealed individual carton contains the following equipment:

(1) Original Bently Nevada 128987-130-00-00 3300 XL 8 mm Reverse Mount Probe

(2) Factory-installed male miniature coaxial ClickLoc connector terminal

(3) Removable composite connection sleeve protector

(4) Complete material traceability card and individual physical calibration sheet

Premium Cargo Security & Distribution Dispatch

Our international logistics hub processes and dispatches all verified industrial orders within 2-7 days after confirming payment details. We route all critical machinery components through express global carriers, including DHL, FedEx, and UPS, to ensure rapid, fully trackable, and insured delivery to your plant site.

Our warehouse wraps each 13.0-meter probe assembly within heavy-duty anti-static industrial packaging sheets before securing it into customized shock-absorbing foam inserts. This strict packaging process provides complete protection against electrostatic discharge, severe transit drops, and ambient moisture entry along international shipping routes.

Site Machinery Instrumentation Diagnostics

Q1: What specific installation advantage does a reverse-mount probe offer over standard front-mount variants?

A1: A reverse-mount probe configuration solves access limitations where the exterior of the machine casing offers no entry port or has limited external clearance space. Technicians install this probe from inside the bearing housing or machinery enclosure by threading it into an internal bracket or sleeve. The integrated cable then exits through a small hole, simplifying internal wiring layout.

Q2: Can I add a standard 3300 XL extension cable to this 13-meter probe assembly?

A2: No. The 128987-130-00-00 probe features a special 13.0-meter long self-contained electrical length configuration. Standard 3300 XL Proximitor sensors require an exact total loop length (typically 5.0 or 9.0 meters). This 13-meter probe connects to a specialized long-range Proximitor calibrated for a matching 13-meter loop layout. Adding another extension cable alters system impedance, ruins calibration, and causes severe tracking errors.

Q3: What circuit failure does a constant -24 VDC output from the Proximitor indicate?

A3: A constant -24 VDC saturation signal indicates an open-circuit fault within the sensor loop. Inspect the miniature ClickLoc connection at the terminal end for a loose coupling or internal moisture. Test the continuity of the center conductor and outer shield along the 13-meter run using a digital multimeter to locate any physical breaks in the cable.

Q4: Why does the unarmored cable version require routing through metal conduit?

A4: The unarmored design provides excellent physical flexibility for long cable runs but lacks a rigid defense against sharp mechanical cuts or heavy physical impacts. Routing this unarmored line through grounded metal conduit protects the coaxial core from structural tearing and provides essential shielding against environmental electromagnetic noise.