Bently Nevada 330104-00-08-50-02-CN Proximity Transducer – 3300 XL

Bently Nevada 330104-00-08-50-02-CN: 8 mm Eddy Current Proximity Transducer in Rotating Machinery Protection Loops

The Bently Nevada 330104-00-08-50-02-CN is an 8 mm non-contact eddy current proximity transducer forming the sensing front-end of the 3300 XL Proximity Transducer System. In a machinery protection loop, this probe converts the physical gap between its tip and a conductive target shaft into a proportional DC voltage signal — nominally –18 VDC at the calibrated midpoint — which is then conditioned by a matched Proximitor oscillator/demodulator before being processed by a 3500 Series monitor rack. The transducer’s role is therefore deterministic: it is the primary signal source for radial shaft vibration (dynamic), axial shaft position (static), differential expansion, and rotational speed (keyphasor) measurements on critical rotating assets including gas turbines, centrifugal compressors, steam turbines, and high-speed pumps.

The suffix breakdown of 330104-00-08-50-02-CN encodes the full mechanical and electrical configuration: probe series 330104, standard mounting thread (00), 8 mm tip diameter (08), 5.0 m extension cable (50), 2.0 m integral cable (02), and standard temperature/connector variant (CN). This configuration is among the most widely deployed in the 3300 XL family, covering the majority of API 670-compliant installations where cable runs between the probe and the Proximitor are in the 5-metre range — typical for compressor trains and turbine pedestals where the junction box is mounted at mid-height on the machine skid.

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Technical Parameters

Hardware Logical Analysis

The 330104-00-08-50-02-CN operates on the principle of high-frequency eddy current induction. The probe tip houses a wound coil driven by the Proximitor at a carrier frequency of approximately 1.0 MHz. When the probe tip approaches a conductive target, eddy currents are induced on the target surface, loading the coil and reducing its Q-factor. The Proximitor’s demodulator circuit converts this impedance change into a linear DC output voltage proportional to the probe-to-target gap. The 8 mm tip geometry is optimized for a linear range of 0.25 mm to 2.26 mm — a window that accommodates both the static installation gap (typically set at 1.0–1.27 mm, or 40–50 mil) and the full dynamic vibration excursion expected on API 670-class machinery.

EMC Design: The coaxial cable architecture of the 330104 series provides inherent shielding against radiated electromagnetic interference. The outer braid of the integral and extension cables is grounded at the Proximitor end only (single-point grounding), preventing ground loop currents that would otherwise introduce 50/60 Hz noise into the measurement signal. In environments with high-frequency switching drives (VFDs operating at 2–16 kHz), the cable’s characteristic impedance and the Proximitor’s input filtering maintain signal integrity without additional shielding conduit in most installations.

Thermal Stability: The probe body’s 316 stainless steel construction and the PTFE-insulated integral cable maintain dimensional and electrical stability across the rated –35 °C to +177 °C range. Thermal expansion of the probe body is accounted for in the calibration curve, ensuring that temperature-induced gap changes do not introduce measurement offset beyond the ±0.5% linearity specification. For installations near exhaust casings or bearing housings where temperatures exceed 150 °C, the CN suffix configuration is the appropriate standard selection; high-temperature variants (HT suffix) are available for applications exceeding 177 °C.

Extension Cable Impedance Matching: The 5.0 m extension cable (330130 series, matched) is electrically characterized to maintain the system’s calibrated scale factor of 7.87 V/mm. Substituting non-matched cables — even of the same physical length — will shift the scale factor and introduce linearity errors that cannot be corrected by monitor rack gain adjustments alone. The CN suffix also specifies the connector type at the Proximitor interface, ensuring mechanical and electrical compatibility with standard 3300 XL Proximitor housings without adapter hardware.

System Integration Benefits

• Drop-in API 670 Compliance: The 330104-00-08-50-02-CN meets API 670 5th Edition requirements for proximity transducer systems, allowing direct use in new installations and like-for-like replacements without re-engineering the protection loop or resubmitting for third-party compliance review.
• Deterministic Real-Time Response: With a flat frequency response from DC to 10,000 Hz (–3 dB), the transducer faithfully captures sub-synchronous, synchronous, and super-synchronous vibration components up to the 10th harmonic of a 1,000 RPM machine — essential for accurate orbit plot generation and rotor dynamic diagnostics in 3500 Series monitors.
• Zero Mechanical Wear on Target: Non-contact measurement eliminates probe-to-shaft contact, removing any risk of shaft scoring or probe tip wear during high-vibration transient events such as startup, shutdown, or surge. This is particularly significant on compressor trains where shaft surface finish is critical to seal performance.
• Dual-Use Static and Dynamic Measurement: The DC-coupled output simultaneously carries the static gap (axial position or radial centerline shift) and the dynamic vibration signal. A single probe installation therefore provides both position trending data for alignment monitoring and vibration amplitude data for protection — reducing the total probe count per measurement plane.
• Diagnostic Transparency via Gap Voltage Monitoring: The –18 VDC nominal output at the calibrated gap allows maintenance engineers to verify probe installation gap without a separate gap meter. Monitoring the DC bias voltage at the Proximitor output directly confirms whether the probe is within its linear range, simplifying commissioning and periodic verification.
• Seamless 3500 Series Monitor Integration: When paired with the 3300 XL 8 mm Proximitor (e.g., 330180 series), the system integrates directly into 3500/22M, 3500/40M, and 3500/42M monitor modules. The monitor’s internal transducer health check continuously verifies that the Proximitor output is within the expected voltage window, generating a transducer not OK (TNK) alert if the probe is open-circuit, short-circuit, or out of gap — providing continuous self-diagnostic coverage without additional hardware.
• Keyphasor Compatibility: The 330104-00-08-50-02-CN can be configured as a Keyphasor transducer by targeting a once-per-revolution notch or projection on the shaft. The resulting pulse train provides the phase reference required for synchronous averaging, 1X/2X vector analysis, and balancing calculations in System 1 software — enabling full rotor dynamic analysis from a single transducer type.
• Reduced Commissioning Time: Factory calibration of the matched probe-cable-Proximitor system eliminates field calibration requirements. The system is shipped as a pre-characterized set; the commissioning engineer sets the installation gap to the specified midpoint and verifies the DC output voltage — a procedure that typically takes under 15 minutes per measurement plane.

Quality Assurance & Global Logistics

Every Bently Nevada 330104-00-08-50-02-CN unit supplied by siemensplc.com is sourced through documented supply channels with full part number and revision traceability. Prior to dispatch from our Xiamen, China facility, each unit undergoes physical inspection covering probe body integrity, cable jacket condition, connector seating, and part number label verification against the order specification. Units are packaged in anti-static, moisture-resistant packaging with foam cushioning to protect the probe tip geometry and cable terminations during international transit.

Shipping is arranged via DHL Express, FedEx International Priority, or UCP depending on destination and urgency. Standard transit times from Xiamen to major industrial hubs are 3–5 business days to Southeast Asia, 5–7 business days to Europe and the Middle East, and 5–8 business days to North America. For emergency maintenance situations, same-day dispatch is available for in-stock units when orders are confirmed before 14:00 CST. All shipments include full tracking and commercial invoice documentation for customs clearance. A 12-month warranty covers manufacturing defects; units are replaced or credited upon return and inspection.

Contact Information

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