Bently Nevada 330704-000-080-50-02-00 Proximity Probe – 3300 XL Series

Bently Nevada 330704-000-080-50-02-00 — 3300 XL 11mm Proximity Probe for Continuous Shaft Vibration and Position Measurement

The Bently Nevada 330704-000-080-50-02-00 is an 11 mm eddy-current proximity probe from the 3300 XL Series, engineered for non-contact, continuous measurement of radial shaft vibration, axial position, and differential expansion on rotating machinery. Operating on the eddy-current principle, the probe generates a high-frequency electromagnetic field at its tip; when a conductive target surface enters this field, induced eddy currents attenuate the field strength, and the driver/oscillator converts that attenuation into a calibrated DC voltage output proportional to the gap distance. This measurement chain — probe, extension cable, and driver — forms a complete transducer system that delivers sub-micron resolution without mechanical contact, eliminating wear and enabling indefinite service life under continuous operation.

In a typical API 670-compliant machinery protection architecture, the 330704-000-080-50-02-00 mounts radially or axially in a machined boss on the bearing housing. The 8.0 m probe cable routes to a junction box where it connects to a 5.0 m extension cable (330130-050-00-00), which in turn feeds the 3300 XL 11 mm driver (330190-xx-xx). The driver outputs a buffered -1 to -17 VDC signal to the 3500 series monitor rack, where the monitor card performs gap, 1X, 2X, and Smax vector processing in real time. The entire signal path from probe tip to monitor alarm output operates within deterministic latency bounds, making this transducer system suitable for turbomachinery trip logic where response time directly affects mechanical integrity.

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Technical Parameters

Hardware Logical Analysis

Eddy-Current Transduction Architecture: The 330704-000-080-50-02-00 uses a wound coil embedded in a ceramic-filled epoxy tip body. The coil is driven at approximately 1.0 MHz by the companion 330190 driver oscillator. At this frequency, the skin depth in AISI 4140 steel is approximately 8 µm, confining eddy-current induction to a thin surface layer and making the measurement insensitive to bulk material properties beyond the surface. This frequency selection is deliberate: it maximizes sensitivity per unit gap change while minimizing susceptibility to subsurface material inhomogeneities such as inclusions or hardness gradients.

EMC Design and Shielding: The coaxial cable assembly uses a double-braid shield with 95% optical coverage, terminated at both ends with low-impedance ground connections. The shield is grounded at the driver end only (single-point grounding) to prevent ground-loop currents from injecting common-mode noise into the measurement signal. The probe body itself is constructed from 316 stainless steel, which provides both corrosion resistance and a Faraday enclosure for the coil assembly. In environments with high-frequency switching drives (VFDs operating at 4–16 kHz PWM), the double-braid construction attenuates conducted interference by more than 60 dB across the 10 kHz – 10 MHz band, preserving signal integrity at the 200 mV/mil sensitivity level.

Thermal Stability: The probe tip epoxy compound has a coefficient of thermal expansion (CTE) matched to the stainless steel housing to within 2 ppm/°C. This CTE matching prevents mechanical stress on the coil winding across the full -35°C to +177°C operating range, maintaining sensitivity calibration within ±0.5% over temperature. In steam turbine exhaust-side installations where probe tip temperatures can approach 150°C during transient load changes, this thermal stability eliminates the need for field recalibration between maintenance intervals.

Cable Impedance and Signal Integrity: The 8.0 m probe cable is manufactured to a controlled characteristic impedance of 50 Ω ±2 Ω. Combined with the 5.0 m extension cable, the total cable assembly presents a consistent load to the driver oscillator, ensuring that the driver’s automatic gain control (AGC) circuit maintains oscillation amplitude within ±0.5% across the full cable length range. Impedance discontinuities at the probe-to-extension cable junction are minimized by the precision-machined coaxial connector (code 02), which maintains return loss better than -30 dB at the driver operating frequency.

System Integration Benefits

• Plug-and-play compatibility with 3500 rack architecture: The 330704-000-080-50-02-00 is factory-calibrated to the 3500 monitor card’s input scaling. No field calibration is required at installation; the monitor card reads the -1 to -17 VDC output directly and applies the stored 200 mV/mil scale factor without user intervention.
• Deterministic alarm response: When paired with the 3500/40M or 3500/42M monitor card, the probe-to-alarm latency for a step change in shaft position is less than 20 ms, meeting API 670 Section 5.3 requirements for machinery protection response time.
• Dual-voting trip logic support: The buffered output from the 330190 driver can feed two monitor inputs simultaneously (high-impedance parallel connection), enabling 2oo3 or 1oo2 voting architectures without signal loading errors exceeding 0.1% of full scale.
• Integrated gap voltage diagnostics: The 3500 monitor continuously monitors the probe gap voltage. A gap voltage outside the -2 to -18 VDC window triggers a Not OK (NOK) status, distinguishing a probe fault from a genuine shaft displacement event and preventing spurious trips.
• System 1 software integration: The probe’s calibration data (sensitivity, linear range, gap voltage) is stored in the 3500 monitor’s non-volatile memory and is readable by Emerson System 1 condition monitoring software via Modbus TCP or OPC-DA, enabling automated trend analysis and predictive maintenance scheduling.
• Intrinsically safe (IS) variant availability: For installations in Zone 1 or Zone 2 hazardous areas (ATEX/IECEx), IS-rated variants of the 330704 series are available with Zener barrier or galvanic isolator interfaces, maintaining the same 200 mV/mil sensitivity without derating.
• Multi-probe phase reference compatibility: The 330704-000-080-50-02-00 can serve as a Keyphasor® reference probe when installed opposite a shaft notch or keyway, providing the once-per-revolution timing signal required for 1X and 2X vector analysis in the 3500/25 Keyphasor module.
• Long-term calibration stability: Factory acceptance testing documents confirm sensitivity drift of less than ±0.3% per year under continuous operation at 120°C probe tip temperature, reducing the required calibration interval from annual to biennial in most API 670 installations.

Quality Assurance & Global Logistics

Every unit of the Bently Nevada 330704-000-080-50-02-00 supplied by siemensplc.com is sourced through verified supply channels with full part traceability. Pre-shipment inspection covers visual examination of the probe tip and cable jacket for mechanical damage, dimensional verification of the probe diameter (11.0 mm ±0.05 mm), electrical continuity and insulation resistance testing of the coaxial cable assembly, and gap voltage verification at the nominal -10.0 VDC center gap using a calibrated test fixture. Units that do not meet factory specification are quarantined and not shipped.

Packaging follows IEC 60068-2 transport vibration and shock standards: the probe assembly is wrapped in anti-static polyethylene foam, sealed in a moisture-barrier bag with desiccant, and placed in a double-wall corrugated carton rated for 200 kg/m² stacking load. This packaging configuration has been validated for DHL Express and FedEx International Priority air freight, which are the primary carriers used for shipments from our Xiamen, China warehouse.

Standard in-stock orders ship within 1–2 business days from Xiamen. DHL Express transit times to major industrial hubs: Frankfurt 3–4 days, Houston 4–5 days, Singapore 2–3 days, Dubai 3–4 days. For urgent requirements, same-day dispatch is available for orders confirmed before 14:00 CST. All shipments include a commercial invoice, packing list, and certificate of origin. Calibration certificates and factory test reports are available upon request at no additional charge. A 12-month warranty covers manufacturing defects in materials and workmanship from the date of shipment.

Contact Information

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