Bently Nevada 330903-00-25-05-02-00 Proximity Probe – 3300 XL Series

Bently Nevada 330903-00-25-05-02-00 — 8mm Eddy-Current Proximity Probe for Continuous Shaft Vibration Monitoring

The Bently Nevada 330903-00-25-05-02-00 is an 8 mm eddy-current proximity probe belonging to the 3300 XL Proximity Transducer System. It is engineered for continuous, non-contact measurement of radial shaft vibration and axial position displacement in rotating machinery operating under demanding industrial conditions. The probe delivers a DC-coupled analog output that is directly proportional to the gap between the probe tip and the conductive target surface, enabling real-time machinery protection and condition monitoring without mechanical contact or wear.

In a closed-loop machinery protection architecture, this probe functions as the primary sensing element. Its output feeds into a Bently Nevada oscillator-demodulator driver — typically the 330180 or 330185 series — which converts the raw impedance change into a calibrated DC voltage signal. That signal is then processed by a 3500-series monitor rack to generate alarm and trip outputs. The deterministic signal chain from probe tip to relay output is what makes the 3300 XL system the reference standard for API 670-compliant turbomachinery protection worldwide.

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

Technical Parameters

Hardware Logical Analysis

The 330903-00-25-05-02-00 operates on the principle of high-frequency eddy-current induction. The probe tip houses a wound coil driven by an oscillator within the paired 330180/330185 driver at a carrier frequency of approximately 1.0 MHz. When the conductive target surface enters the electromagnetic field generated by the coil, eddy currents are induced in the target, loading the coil and reducing its effective inductance and Q-factor. The driver’s demodulator circuit converts this impedance shift into a linear DC voltage output with a calibrated slope of 200 mV/mil (7.87 V/mm).

EMC and Shielding Architecture: The integral armored cable between the probe body and the driver is a triaxial construction — inner signal conductor, driven shield at oscillator potential, and outer grounded armor. This driven-shield topology eliminates capacitive coupling between the signal conductor and ground, preserving signal integrity across the full 5 m cable run without sensitivity degradation. The outer armor provides mechanical protection against abrasion, hydraulic fluid, and process chemical exposure typical in turbomachinery environments.

Thermal Stability: The probe coil assembly is encapsulated in a thermally stable polymer compound rated to 177 °C. The coil winding uses a controlled-expansion bobbin material to minimize sensitivity drift across the operating temperature range. Factory calibration is performed at 25 °C against an AISI 4140 target, and the system-level temperature coefficient is specified to remain within ±0.5% of full-scale output across the rated thermal envelope when used with the matched driver.

Mechanical Mounting: The probe body is threaded M10 × 1.0 mm for direct installation into standard proximity probe mounting brackets. The 25 mm integral extension positions the probe tip at the correct standoff distance from the shaft surface, establishing the nominal gap voltage of approximately –10.4 VDC at a 1.0 mm air gap. This nominal gap point sits at the center of the linear range, providing symmetric measurement headroom for both inward and outward shaft displacement events.

Hazardous Area Compliance: At the system level, the 3300 XL assembly carries ATEX Ex ia IIC T4 certification and FM/CSA intrinsic safety approvals, permitting installation in Zone 1 / Division 1 classified areas. The intrinsic safety barrier is implemented within the driver module, not the probe itself, which means the probe cable and tip can be routed through hazardous zones without additional conduit sealing requirements beyond those mandated by local electrical codes.

System Integration Benefits

• Direct API 670 compliance: The 330903-00-25-05-02-00 is a listed component within the Bently Nevada 3300 XL system qualification, satisfying API 670 Section 5 requirements for proximity transducer systems without additional field calibration or documentation burden.
• Deterministic signal latency: The DC-coupled output path from probe tip through driver to monitor input introduces less than 100 µs of signal latency, ensuring that the protection system can respond to shaft excursions within the monitor’s configured response time — typically 20 ms for a 3500-series rack.
• Plug-compatible with existing 3300 infrastructure: The coaxial connector and cable impedance characteristics are identical across the 3300 XL probe family, allowing direct substitution into existing cable runs and driver inputs without re-termination or re-calibration of the driver.
• Dual-use measurement capability: A single probe installation simultaneously provides radial vibration (AC component) and average shaft centerline position (DC component) data to the monitor, eliminating the need for separate displacement sensors and reducing penetration count through the bearing housing.
• Wide frequency bandwidth for sub-synchronous detection: The DC–10,000 Hz flat response captures not only 1× and 2× running-speed vibration but also sub-synchronous instability phenomena such as oil whirl (typically 0.43–0.48×) and oil whip, which are critical failure precursors in fluid-film bearing machines.
• Integral extension eliminates field-assembly error: The 25 mm extension is factory-assembled and calibrated as a unit with the probe body. This eliminates the connector resistance variability and mechanical misalignment that can occur when field-assembled probe-plus-extension combinations are used, improving measurement repeatability across installations.
• Diagnostic transparency via gap voltage monitoring: The –10.4 VDC nominal gap voltage is continuously observable at the driver output terminal. Deviations from this nominal value during operation indicate shaft centerline migration, bearing wear, or probe mounting shift — providing a passive diagnostic channel that requires no additional instrumentation.
• Long-term calibration stability: The eddy-current sensing mechanism has no moving parts, no contact wear, and no optical degradation mechanisms. Field experience across the 3300 XL product generation documents sensitivity drift of less than 1% over 10-year service intervals in clean industrial environments, supporting extended calibration intervals under IEC 61511 functional safety management programs.

Quality Assurance & Global Logistics

Every unit of the Bently Nevada 330903-00-25-05-02-00 supplied through siemensplc.com is sourced from verified distribution channels with full traceability documentation. Prior to dispatch, each probe undergoes a pre-shipment inspection protocol covering physical integrity of the probe body and tip, continuity and insulation resistance of the armored cable, connector condition and coaxial impedance check, and verification of the part number label against the order specification.

Units are packaged in anti-static foam-lined cartons with desiccant inserts to prevent moisture ingress during transit. Export documentation — including commercial invoice, packing list, and certificate of origin — is prepared in compliance with Chinese customs regulations and the import requirements of the destination country. HS Code 9031.80 applies to proximity transducer systems for most jurisdictions.

Shipments originate from our warehouse in Xiamen, China. Standard international delivery is executed via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, with transit times of 3–7 business days to most destinations in North America, Europe, Southeast Asia, and the Middle East. For time-critical plant shutdowns or emergency replacements, same-day dispatch is available for in-stock units when orders are confirmed before 14:00 CST. All shipments are fully insured and tracked from dispatch to delivery confirmation.

A 12-month warranty from the date of shipment covers manufacturing defects and performance deviations from the published specification. Warranty claims are processed with replacement unit dispatch within 5 business days of defect confirmation, minimizing plant downtime exposure.

Contact Information

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