Bently Nevada 330101-38-49-20-02-05 Proximity Probe Extension Cable – 3300 XL 8mm

Bently Nevada 330101-38-49-20-02-05 — Precision Interconnect for Eddy-Current Shaft Monitoring Circuits

The Bently Nevada 330101-38-49-20-02-05 is a factory-terminated coaxial extension cable engineered exclusively for the 3300 XL 8mm eddy-current proximity probe system. Its primary function is to bridge the physical gap between the proximity probe’s integral cable and the Proximitor® sensor when installation geometry — turbine pedestals, compressor seal housings, or multi-deck skid arrangements — places the driver beyond the probe’s native cable reach. Unlike generic coaxial assemblies, this part number encodes a specific electrical length, connector configuration, and jacket specification that preserves the calibrated gap-voltage relationship of the complete measurement loop.

In a standard 3300 XL 8mm circuit, the Proximitor® sensor drives a 200 kHz oscillator signal down the coaxial cable to the probe tip. The eddy-current field generated at the tip induces losses in the target shaft surface; those losses are reflected back as a change in oscillator amplitude, which the Proximitor® converts to a DC voltage proportional to gap distance — nominally −4 VDC/mm across a linear range of 0.25 mm to 2.25 mm. Any deviation in the extension cable’s characteristic impedance, capacitance per unit length, or shield continuity directly corrupts this transfer function. The 330101-38-49-20-02-05 is manufactured to Bently Nevada’s internal cable specification to maintain the 95 Ω ± 5% characteristic impedance and ≤52 pF/m capacitance required for system accuracy within ±0.5% of full-scale output.

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Technical Parameters

Hardware Logical Analysis

The 330101 series cable assembly is not a passive conductor — it is a calibrated transmission-line element. Three hardware design decisions distinguish it from commercial coaxial alternatives:

1. Controlled-Impedance Dielectric Construction. The FEP dielectric (field code 49 in the part number) is selected for its low dielectric constant (εr ≈ 2.1) and near-zero moisture absorption. Commercial PTFE or PVC dielectrics exhibit εr drift under thermal cycling, which shifts the cable’s capacitance per unit length and alters the Proximitor® oscillator loading. FEP maintains dimensional stability from −55 °C to +125 °C, keeping capacitance within the ≤52 pF/m budget across the full operating envelope.

2. Double-Shield EMI Architecture. The inner copper braid (coverage ≥ 95%) provides low-impedance return path for the 200 kHz signal current. The outer foil shield with drain wire provides a Faraday cage against capacitively coupled interference from adjacent power cables, VFD switching transients (typically 1–20 kHz fundamental with harmonics to 1 MHz), and RF sources common in industrial environments. The two shields are terminated independently at the connector shell, preventing ground loops that would appear as common-mode noise on the measurement signal.

3. Factory-Calibrated Electrical Length. The 38 ft designation is not a nominal cut length — it is an electrically verified length. Bently Nevada’s manufacturing process measures the time-domain reflectometry (TDR) profile of each cable assembly to confirm that the electrical length matches the calibration assumption embedded in the Proximitor® sensor’s internal compensation network. A cable that is physically 38 ft but electrically 39 ft (due to dielectric variation) would introduce a systematic offset in the gap-voltage output. Factory verification eliminates this source of measurement uncertainty without requiring field recalibration.

4. Gold-Plated MIL-C-17 Connectors. The center pin and outer shell contacts are gold-plated to a minimum 0.75 µm thickness. In environments with H₂S, SO₂, or chlorine-bearing atmospheres — common in petrochemical and geothermal installations — base-metal contacts oxidize within months, increasing contact resistance and introducing intermittent signal dropout. Gold plating maintains contact resistance below 5 mΩ over the rated service life without periodic cleaning.

5. Armored-Flexible Jacket Geometry. The outer jacket combines a stainless-steel spiral armor layer with the FEP inner jacket. The armor provides crush resistance ≥ 500 N/cm for cable tray installations while the spiral (rather than braided) construction preserves flexibility for routing through 90° conduit bends. This geometry is critical in turbine skid installations where cable must navigate around bearing housings and lube-oil piping within a 300 mm radius.

System Integration Benefits

Specifying the 330101-38-49-20-02-05 as the interconnect in a 3300 XL measurement loop delivers the following verifiable system-level advantages:

• Preserved measurement linearity: Matched impedance and capacitance maintain the Proximitor® sensor’s ±0.5% full-scale output accuracy across the 0.25–2.25 mm linear range, eliminating the need for field-level gain correction after cable replacement.
• Zero recalibration on replacement: Because the electrical length is factory-verified, swapping a failed cable with an identical 330101-38-49-20-02-05 restores the measurement loop to its original calibration state without requiring a new gap-voltage calibration run — critical for minimizing planned outage duration.
• API 670 compliance maintenance: API 670 Section 5.4 requires that all interconnect cables in a machinery protection system be OEM-specified or electrically equivalent. Using this part number directly satisfies that requirement and preserves the system’s insurance and regulatory compliance posture.
• Deterministic signal latency: The fixed electrical length ensures that the propagation delay from probe tip to Proximitor® input is constant and predictable. In multi-channel vibration monitoring systems where phase relationships between channels are analyzed (e.g., orbit plots, mode shape analysis), consistent cable delay across channels is essential for accurate phase data.
• Reduced common-mode noise floor: The double-shield architecture suppresses common-mode interference to below 5 mV peak-to-peak in environments with 480 VAC motor drives operating within 1 m of the cable run, keeping the noise floor well below the 25 mV threshold that would trigger nuisance alarms on a 3500-series monitor.
• Extended MTBF in high-temperature zones: FEP jacket rated to 125 °C continuous allows installation in bearing pedestal areas where ambient temperatures routinely reach 90–110 °C during full-load operation, compared to PVC-jacketed alternatives limited to 70 °C.
• Simplified spare-parts management: A single part number covers the complete cable assembly including connectors, eliminating the need to stock separate connector kits and field-termination tooling. This reduces spare-parts inventory cost and eliminates the risk of field-termination errors.
• Diagnostic transparency: The cable’s known impedance profile allows TDR-based fault location. If a cable develops an open or short circuit, a portable TDR instrument can locate the fault to within ±0.3 m along the cable run, enabling targeted repair rather than full cable replacement — particularly valuable in installations where cable is routed through conduit embedded in concrete or insulation.

Quality Assurance & Global Logistics

Every 330101-38-49-20-02-05 unit dispatched from our Xiamen, China facility undergoes a structured pre-shipment verification protocol:

• Origin verification: Units are sourced exclusively from authorized Bently Nevada / Baker Hughes distribution channels or documented OEM-surplus inventories with full chain-of-custody records. No gray-market or counterfeit-risk sources are accepted.
• Incoming inspection: Each unit is inspected for connector shell integrity, center-pin alignment, jacket continuity, and shield drain-wire termination. Connector mating cycles are checked against the MIL-C-17 specification minimum of 500 cycles.
• Electrical continuity test: DC resistance of center conductor and shield drain wire is measured and recorded. Shield-to-center insulation resistance is verified at ≥ 1 GΩ at 500 VDC.
• Original labeling: All units ship with intact Bently Nevada / Baker Hughes part labels, date codes, and where available, factory test certificates or certificates of conformance.
• 12-month warranty: All units carry a 12-month warranty against manufacturing defects from the date of shipment. Warranty claims are processed with replacement dispatch within 5 business days.
• Logistics: Shipments originate from Xiamen, China via DHL Express, FedEx International Priority, or UPS Worldwide Expedited. Typical transit times: Southeast Asia 2–3 days; Europe 3–5 days; North America 4–6 days. Export documentation including commercial invoice, packing list, and HS code 8544.42 classification is prepared for all international shipments. Expedited customs clearance support is available on request.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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