Bently Nevada 330930-040-00-00 Proximitor Extension Cable – 3300 XL Series

Bently Nevada 330930-040-00-00 Proximitor Extension Cable — Signal Transmission Architecture in Eddy-Current Measurement Loops

The Bently Nevada 330930-040-00-00 is a 40 ft (12.19 m) factory-terminated coaxial extension cable engineered for the 3300 XL proximity transducer system. Its primary function is to bridge the physical gap between the proximity probe tip and the Proximitor® sensor housing, completing the three-component eddy-current measurement chain: probe → extension cable → Proximitor® sensor. Within this chain, the extension cable is not a passive conductor — it is a precision transmission line whose characteristic impedance, distributed capacitance, and dielectric properties are tightly controlled to preserve the 1 MHz carrier signal generated by the Proximitor® oscillator circuit.

In rotating machinery protection applications governed by API 670, the extension cable must maintain a stable electrical environment across the full operating temperature range. Any deviation in cable capacitance per unit length directly shifts the Proximitor® output voltage-to-gap calibration curve, introducing systematic measurement error into radial vibration, axial position, and eccentricity channels. The 330930-040-00-00 is manufactured to Bently Nevada’s internal cable specification, ensuring matched impedance with the 3300 XL probe series and eliminating the need for field recalibration when replacing a like-for-like unit.

Real-time Stock & RFQ: [email protected] | WhatsApp: +86 18359268345

Technical Parameters

Hardware Logical Analysis

The 330930-040-00-00 operates as a controlled-impedance transmission line within a 1 MHz carrier-frequency measurement loop. The Proximitor® sensor drives a sinusoidal oscillator signal down the cable to the probe coil. The probe coil generates an alternating magnetic field; when a conductive target (rotor shaft) enters the field, eddy currents are induced, loading the coil and reducing the oscillator amplitude. The Proximitor® demodulates this amplitude change into a DC voltage proportional to the air gap — typically –200 mV/mil (–7.87 V/mm) for 8 mm probes.

For this signal chain to remain accurate, the extension cable must satisfy three simultaneous electrical constraints:

1. Impedance Continuity: The cable’s 50 Ω characteristic impedance must be maintained from connector to connector without discontinuities. Any impedance mismatch at the connector interface creates a partial signal reflection at 1 MHz, introducing standing-wave distortion that manifests as a static offset error in the gap voltage output. Bently Nevada’s factory-crimped connectors are dimensionally controlled to maintain the 50 Ω geometry through the connector transition zone.

2. Capacitance Budget Management: The Proximitor® sensor’s oscillator circuit is tuned to a specific total cable capacitance (probe cable + extension cable combined). The 330930-040-00-00 is manufactured with a tightly controlled capacitance per foot, ensuring the total system capacitance remains within the Proximitor® sensor’s rated operating window. Exceeding this window shifts the oscillator frequency, compressing the linear output range and reducing sensitivity.

3. EMC Shielding Integrity: Industrial machinery environments expose cables to high-intensity electromagnetic interference from variable-frequency drives (VFDs), motor starters, and high-current bus bars. The 330930-040-00-00’s braided copper shield (≥95% optical coverage) provides a continuous Faraday enclosure around the inner conductor. The shield is grounded at the Proximitor® sensor end only (single-point grounding), preventing ground-loop currents from injecting common-mode noise into the measurement signal. This architecture maintains signal-to-noise ratios sufficient to resolve vibration amplitudes below 0.5 mil pk-pk in the presence of ambient EMI fields exceeding 10 V/m.

The PTFE dielectric insulation on the inner conductor provides a stable permittivity (εr ≈ 2.1) across the full –55°C to +125°C operating range. Unlike PVC-insulated cables, PTFE does not exhibit significant permittivity drift with temperature, which would otherwise cause the cable capacitance — and therefore the Proximitor® calibration — to shift as the machine reaches operating temperature.

System Integration Benefits

• Zero-recalibration replacement: Substituting a 330930-040-00-00 for a failed unit of identical length requires no Proximitor® gap voltage re-verification, reducing machinery downtime to the physical cable swap time only.
• Deterministic measurement latency: The matched-impedance transmission line eliminates signal reflection delays that would otherwise introduce phase error in synchronous vibration (1X) amplitude and phase measurements used for balancing and alignment diagnostics.
• Diagnostic transparency: The cable’s low-loss construction preserves the full dynamic range of the Proximitor® output, allowing the 3500 monitor to resolve both slow-roll runout vectors and high-frequency sub-synchronous instability events without signal compression.
• API 670 compliance path: Using OEM-specified cables is a prerequisite for demonstrating API 670 compliance during machinery protection system audits. Third-party cables with uncontrolled capacitance specifications invalidate the system’s certified calibration.
• Temperature-stable calibration: PTFE dielectric maintains capacitance within ±2% from ambient to 125°C, ensuring the Proximitor® output scale factor remains within the ±1% accuracy specification across the full machine operating envelope.
• Reduced common-mode noise floor: Single-point shield grounding architecture suppresses 50/60 Hz power-frequency interference and VFD switching harmonics, maintaining the noise floor below 25 mV pk-pk — well within the 3500 monitor’s alarm setpoint resolution of 0.1 mil.
• Mechanical durability in harsh installations: The armored outer jacket resists abrasion, hydrocarbon fluid exposure, and mechanical impact in turbine enclosures and compressor trains where cable routing is constrained and maintenance access is limited.
• Interoperability with System 1 software: When used within a fully OEM-specified cable set, the 3500 monitor’s System 1 Evolution integration provides accurate gap voltage trending, enabling predictive maintenance workflows based on long-term shaft centerline position drift analysis.

Quality Assurance & Global Logistics

Every unit of the 330930-040-00-00 supplied by siemensplc.com is sourced through verified channels and subjected to incoming inspection prior to dispatch. Connector continuity, shield integrity, and outer jacket condition are verified for each unit. Original manufacturer packaging and documentation — including certificate of conformance where available — are retained and supplied with the shipment.

Our logistics operations are based in Xiamen, China, a major international port city with direct air freight connections to Singapore, Dubai, Frankfurt, Los Angeles, and Tokyo. Standard international shipments are dispatched within 1–3 business days of order confirmation. Expedited air freight options are available for urgent plant maintenance requirements. All export shipments are accompanied by a commercial invoice, packing list, and HS code declaration (HS 8544.42) to facilitate smooth customs clearance in destination countries. We support DDP (Delivered Duty Paid) terms for select destinations — contact us to confirm availability for your country.

A 12-month warranty covers all units against manufacturing defects. Warranty claims are processed with replacement dispatch within 5 business days of defect confirmation. Our technical team, with direct experience in Bently Nevada 3300 XL and 3500 series systems, is available to assist with installation verification, cable length selection, and system compatibility confirmation before purchase.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
© 2026 siemensplc.com. All rights reserved.