Bently Nevada 330707-00-25-10-02-00 Proximity Transducer System – 3300 XL Series

Bently Nevada 330707-00-25-10-02-00 — Matched Eddy Current Proximity Transducer System for Rotating Machinery Protection

The 330707-00-25-10-02-00 is a factory-matched, three-component eddy current proximity transducer system manufactured by Bently Nevada (a Baker Hughes company) within the 3300 XL Series platform. It comprises a 25 mm diameter probe, a 10-metre armored extension cable, and a Proximitor® sensor — all calibrated as a unified measurement chain at the factory. This configuration is the most widely deployed variant in API 670-compliant machinery protection systems for steam turbines, gas turbines, centrifugal compressors, and large rotating equipment in power generation and hydrocarbon processing facilities.

The system operates on the eddy current induction principle. The probe tip houses a wound coil driven by a high-frequency oscillator circuit (nominally 1–2 MHz). When the conductive target surface — typically an AISI 4140 steel shaft journal — enters the electromagnetic field, eddy currents are induced in the target, increasing the load on the oscillator and reducing its amplitude. The Proximitor® sensor demodulates this amplitude-modulated signal into a DC-proportional voltage output ranging from –1 VDC (near gap) to –17 VDC (far gap), with a scale factor of 7.87 V/mm (200 mV/mil). This linear analog output is directly compatible with Bently Nevada 3300 Series monitor input cards and feeds into System 1® condition monitoring software for real-time alarming, trending, and predictive diagnostics.

The –02-00 output suffix designates the standard 200 mV/mil scale factor configuration, which is the default input calibration for the majority of 3300 XL Series monitor channels. The 25 mm probe diameter provides a linear measurement range of 0.25 mm to 2.25 mm (10 to 90 mil), sufficient to capture the full dynamic range of shaft radial displacement in most turbomachinery bearing clearance envelopes. The 10-metre extension cable length accommodates the physical separation between the probe mounting location at the bearing pedestal and the Proximitor® sensor housing, which is typically mounted in a junction box or instrument enclosure away from high-temperature zones.

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Technical Parameters

Hardware Logical Analysis

The 330707-00-25-10-02-00 system’s hardware architecture is built around three interdependent subsystems that must be treated as a single calibrated unit — not interchangeable components.

Probe Oscillator Circuit: The probe contains a precision-wound coil embedded in a thermally stable ceramic former. The coil forms the inductive element of an LC oscillator circuit whose resonant frequency is sensitive to the eddy current loading imposed by the target. The 25 mm probe diameter is selected to provide a field penetration depth and lateral sensitivity profile optimized for shaft diameters in the 50–300 mm range, which covers the majority of turbomachinery journal bearing applications. The ceramic former maintains dimensional stability across the full –35°C to +177°C operating range, preventing thermal drift in the coil geometry that would otherwise introduce measurement error at high bearing temperatures.

Extension Cable Signal Integrity: The 10-metre armored extension cable is not a passive conductor — it is a calibrated transmission line with a defined characteristic impedance matched to the probe oscillator output. The cable’s distributed capacitance and inductance are factored into the factory calibration. Substituting a non-matched cable of different length or construction will shift the oscillator operating point and introduce a scale factor error that cannot be corrected without recalibration. The armored outer jacket provides mechanical protection against abrasion and crush loads in cable trays, while the inner shielding suppresses radiated EMI from adjacent power cables and motor drives — a critical consideration in plant environments where variable-frequency drives (VFDs) generate broadband conducted and radiated noise in the 2–20 kHz range.

Proximitor® Demodulation and EMC Design: The Proximitor® sensor performs amplitude demodulation of the oscillator signal and converts it to the DC output voltage. Its internal circuitry includes a regulated power supply, a precision demodulator, and an output buffer amplifier. The housing is designed with a continuous conductive enclosure that provides Faraday shielding against external electric fields. The power supply input includes transient suppression rated to IEC 61000-4-5 (surge immunity), and the output circuit includes filtering to reject common-mode noise on the signal cable run to the monitor rack. The result is a measurement system with a noise floor below 25 µm pk-pk in typical plant EMC environments — sufficient to resolve sub-synchronous shaft instabilities at amplitudes that would be masked by noise in lesser-quality transducer systems.

Matched-Set Calibration Logic: Factory calibration assigns a unique calibration record to each probe/cable/Proximitor® serial number combination. The calibration verifies scale factor linearity across the full measurement range at three temperatures (–20°C, +25°C, +150°C for the probe), confirming that thermal sensitivity drift remains within ±1% of nominal scale factor across the operating envelope. This matched-set approach eliminates the field calibration step that would otherwise be required when mixing components from different production lots.

System Integration Benefits

• Direct API 670 Compliance: The 330707 system meets all transducer performance requirements of API 670 (5th Edition) for radial vibration and axial position measurement channels, eliminating the need for additional qualification testing during machinery protection system commissioning.
• Zero-Reconfiguration Rack Replacement: The –02-00 scale factor is the factory default for 3300 XL Series monitor input cards. Replacing a failed transducer system with a 330707-00-25-10-02-00 requires no changes to monitor card configuration, alarm setpoints, or System 1® database entries — reducing mean time to repair (MTTR) in critical machinery protection applications.
• DC-to-10 kHz Bandwidth for Multi-Parameter Measurement: A single channel simultaneously captures static gap (DC component for eccentricity and position), 1× and 2× running speed vibration, and subsynchronous instabilities up to 10 kHz — reducing channel count and wiring complexity compared to multi-sensor approaches.
• System 1® Native Integration: The analog output is directly compatible with Bently Nevada System 1® software without signal conditioning adapters. Historical trend data, alarm event logs, and orbit plots are available immediately upon connection to an existing System 1® server.
• High-Temperature Probe for Hot-Section Mounting: The +177°C probe rating permits direct mounting at bearing pedestals on high-pressure steam turbines and gas turbine hot sections without thermal isolation standoffs, simplifying mechanical installation and reducing probe-to-shaft gap setting complexity.
• IP67 Environmental Sealing for Wet and Oily Environments: The probe body and cable connectors are rated IP67, providing complete protection against oil mist, steam condensate, and wash-down water ingress — common in compressor train and pump environments where bearing housings are oil-flooded.
• Deterministic Analog Output for Safety System Integration: The –1 to –17 VDC analog output is a deterministic, fail-safe signal. A broken cable or failed probe drives the output to the supply rail (–24 VDC), which falls outside the normal measurement range and is interpreted by the monitor as a fault condition — providing inherent fail-safe behavior without additional logic.
• Broad Target Material Compatibility with Documented Correction Factors: While the standard calibration targets AISI 4140 steel, Bently Nevada publishes material correction factors for Inconel 718, 17-4 PH stainless, titanium alloys, and other common shaft materials, allowing the same transducer system to be used across mixed-material rotor trains with documented accuracy.

Quality Assurance & Global Logistics

Every 330707-00-25-10-02-00 unit supplied by siemensplc.com is sourced through verified industrial automation supply channels with full traceability to Bently Nevada (Baker Hughes) manufacturing records. Incoming inspection covers visual examination of probe tip, connector condition, and cable armor integrity; dimensional verification of probe tip diameter and thread form; and functional verification of Proximitor® output voltage at a known gap distance against the OEM calibration certificate. Matched probe/cable/Proximitor® serial number sets are confirmed prior to packaging — no mixed-lot assemblies are shipped.

Shipments originate from our warehouse in Xiamen, China. Xiamen is a designated free-trade port with direct access to international air freight hubs (Xiamen Gaoqi International Airport) and sea freight terminals (Xiamen Port), enabling competitive transit times to destinations across Southeast Asia, the Middle East, Europe, and the Americas. Standard export documentation — commercial invoice, packing list, certificate of origin, and certificate of conformance — is prepared for every shipment. DHL Express, FedEx International Priority, and UPI air freight options are available. Typical transit times: 3–5 business days to Europe and North America via express air; 7–14 days via standard air freight. All units are packed in anti-static foam-lined cartons with desiccant to prevent moisture ingress during transit. A 12-month warranty from the date of shipment covers manufacturing defects and functional failures under normal operating conditions.

Contact Information

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