Bently Nevada 330730-080-10-00 Extension Cable – 3300 Series

Bently Nevada 330730-080-10-00: 8-Meter Armored Extension Cable for 3300 Series Proximity Measurement Loops

The Bently Nevada 330730-080-10-00 is an 8-meter (26.2 ft) armored coaxial extension cable purpose-built for the 3300 Series eddy-current proximity measurement system. Its function within the measurement loop is precise and non-negotiable: it transmits the high-frequency oscillator signal from the Proximitor® sensor to the probe tip, and returns the demodulated DC gap voltage back to the monitor — all while maintaining the 95 Ω characteristic impedance that the 3300 system’s signal conditioning circuitry depends on. Any deviation in cable impedance, shield continuity, or dielectric geometry directly corrupts the gap voltage output, producing false vibration or position readings at the monitor. The 330730-080-10-00 eliminates that risk by adhering to Bently Nevada’s OEM coaxial geometry specification across the full 8-meter run.

In rotating machinery protection systems — gas turbines, steam turbines, centrifugal compressors, and large pump trains — the extension cable occupies the most mechanically hostile segment of the measurement chain. It routes through bearing pedestals, across hot pipe racks, and through cable trays exposed to coolant mist, lubricating oil vapor, and continuous vibration. The 330730-080-10-00’s stainless steel armor braid and fluoropolymer dielectric are selected specifically for this environment, not as a general-purpose cable specification.

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Technical Parameters

Hardware Logical Analysis

The 330730-080-10-00 is not a passive conductor — it is an active element in a tuned RF circuit. The 3300 Series Proximitor® sensor drives the probe coil at approximately 1 MHz via the extension cable. The cable’s 95 Ω impedance is matched to the Proximitor’s output stage to prevent standing wave reflections that would modulate the oscillator amplitude and introduce a systematic error into the gap voltage output. Bently Nevada specifies that the total system cable length (probe cable + extension cable) must fall within a defined range for each probe/Proximitor combination; the 330730-080-10-00’s 8-meter length is one of the standard increments in that calibration matrix.

The PTFE dielectric is selected for its near-zero moisture absorption (less than 0.01% by weight per ASTM D570) and stable dielectric constant (εr ≈ 2.1) across the full operating temperature range. A cable dielectric that absorbs moisture or softens at elevated temperature will shift capacitance per unit length, altering the cable’s electrical length and detuning the oscillator — a failure mode that manifests as a slow drift in the gap voltage baseline rather than an abrupt fault, making it difficult to detect without trending data.

The stainless steel interlocked armor provides two distinct functions: mechanical protection against crush loads and rodent damage, and a secondary EMC shield layer. The inner braid shield (≥ 95% coverage) handles high-frequency interference rejection; the outer armor attenuates lower-frequency magnetic field coupling from adjacent power cables and motor drives. Together, they achieve a transfer impedance specification that keeps induced noise below the 3300 monitor’s input noise floor, preserving measurement resolution to the sub-micron level required for API 670 machinery protection.

The MIL-C-5015 style connectors use a gold-plated center pin and a precision-machined dielectric insert to maintain the 95 Ω impedance through the connector body. The coupling nut incorporates a locking feature that prevents vibration-induced loosening — a critical detail in turbine bearing housings where broadband vibration at 10–2000 Hz is continuous during operation. Connector contact resistance is specified at ≤ 5 mΩ, ensuring that the connector junction does not introduce a measurable voltage drop into the −24 VDC supply rail that powers the probe oscillator.

System Integration Benefits

• Calibrated impedance match: The 95 Ω ± 2 Ω specification ensures the Proximitor® oscillator operates at its design point, maintaining the linear gap-voltage transfer function (typically −7.87 V/mm for 8 mm probes) without recalibration when the cable is replaced.
• API 670 compliance path: The 330730-080-10-00 is part of the Bently Nevada system assembly validated against API 670 (5th edition) machinery protection requirements, simplifying compliance documentation for new installations and insurance audits.
• Zero-modification installation: OEM connectors and cable geometry allow direct replacement of existing 330730-series cables without re-termination, re-calibration, or software parameter changes at the 3500 monitor.
• Deterministic signal latency: The cable’s controlled electrical length (velocity of propagation ≈ 69% of c) is accounted for in the Proximitor’s factory calibration, ensuring group delay through the measurement chain remains within the 3500 monitor’s timing budget for real-time protection response (typically less than 20 ms trip response per API 670).
• Diagnostic transparency: A failed or degraded 330730-080-10-00 produces a characteristic signature at the 3500 monitor: the gap voltage shifts outside the −2 V to −18 V linear range, triggering a Not OK (NOK) status output. This allows maintenance teams to isolate cable faults without removing the probe from the bearing housing.
• EMC immunity in VFD-dense environments: The dual-layer shielding (braid + armor) maintains signal integrity in switchgear rooms and motor control centers where variable frequency drives generate broadband conducted and radiated interference from 2 kHz to 150 kHz.
• Thermal stability across process upsets: PTFE dielectric maintains dimensional stability from cryogenic service (LNG compressors, −40 °C) to high-temperature steam turbine pedestals (+85 °C), without the impedance drift associated with PVC or polyethylene dielectrics.
• Reduced spare parts complexity: The 8-meter length covers the majority of turbine and compressor installations where the Proximitor® is mounted on the bearing housing pedestal. Stocking a single cable length reduces warehouse SKU count and eliminates field-cutting errors that invalidate the system calibration.

Quality Assurance & Global Logistics

Every Bently Nevada 330730-080-10-00 supplied by siemensplc.com is sourced through verified industrial channels and subjected to a structured pre-shipment inspection protocol. Physical part number labels are cross-referenced against Bently Nevada’s OEM part numbering schema. Connector bodies, armor terminations, and cable jacket integrity are inspected under magnification. End-to-end coaxial continuity and shield isolation are verified on a calibrated bench fixture before packaging.

Shipments originate from our warehouse in Xiamen, China — a major export hub with direct access to international express carriers. Standard dispatch is within 1–3 business days for in-stock units. Export documentation — commercial invoice, packing list, and certificate of origin — is prepared for every shipment. HS Code 8544.42 (insulated electric conductors, fitted with connectors, for a voltage ≤ 1,000 V) applies to this product. DHL Express, FedEx International Priority, and UPS Worldwide Express are the primary carriers; sea freight consolidation is available for multi-unit project orders. Delivery to major industrial hubs in Europe, the Middle East, Southeast Asia, and the Americas typically completes within 3–7 business days via express service.

A 12-month warranty against manufacturing defects is included with every unit. DOA (dead-on-arrival) replacement is processed within 7 business days of confirmed fault report. Traceable inspection records are available on request for regulated industries (nuclear, offshore, aviation-adjacent).

Contact Information

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