Bently Nevada 330904-00-16-50-02-00 Proximity Transducer – 3300 XL NSv

Bently Nevada 330904-00-16-50-02-00 — Eddy-Current Proximity Transducer for API 670 Machinery Protection

The 330904-00-16-50-02-00 is a three-component eddy-current proximity transducer assembly within Bently Nevada’s 3300 XL NSv (Non-Standard Voltage) platform. It is configured with a 16 mm probe tip, a 5.0 m (50 dm) armored extension cable, and a 2.0 m (20 dm) driver cable. The assembly delivers a calibrated DC voltage output proportional to the gap between the probe face and a conductive target shaft, enabling continuous, non-contact measurement of radial vibration, axial position, and differential expansion in rotating machinery operating under API 670 4th Edition requirements.

This transducer is deployed across steam turbines, gas turbines, centrifugal compressors, large electric motors, and expanders in power generation, LNG, refinery, and petrochemical service. Its NSv output architecture allows direct channel-for-channel replacement in existing 3300 XL monitor installations without reconfiguring monitor bias voltage thresholds — a critical operational advantage during planned maintenance windows where downtime must be minimized.

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

Technical Parameters

Hardware Logical Analysis

The 330904-00-16-50-02-00 operates on the principle of electromagnetic induction impedance variation. The probe coil, driven by the oscillator circuit inside the driver module at a carrier frequency typically between 500 kHz and 2 MHz, generates a focused electromagnetic field at the probe tip. When a conductive target enters this field, eddy currents are induced on the target surface, loading the probe coil and reducing its effective impedance. The driver’s demodulator circuit converts this impedance shift into a proportional DC voltage — the output signal that monitor input cards interpret as a gap measurement.

EMC Design Architecture: The coaxial cable assembly uses a double-shielded construction with a braided outer shield bonded to the driver chassis ground. This configuration attenuates common-mode noise from adjacent power cables and variable-frequency drives (VFDs), which are prevalent in compressor and pump motor installations. The shield termination at the driver end — not at the probe end — prevents ground loop formation that would otherwise introduce 50/60 Hz interference into the displacement signal.

Thermal Stability: The probe body is constructed from 316 stainless steel with a PEEK (polyether ether ketone) tip insert. PEEK’s low thermal expansion coefficient (50 × 10⁻⁶ /°C) relative to the stainless housing minimizes thermally induced dimensional changes at the probe face, preserving calibration accuracy across the full −35 °C to +121 °C operating envelope. This is particularly relevant in steam turbine bearing housings where ambient temperatures can cycle significantly during startup and shutdown sequences.

Cable Signal Integrity: The 5.0 m extension cable is specified with a characteristic impedance matched to the driver’s input network. Impedance mismatch at the cable-driver junction would introduce reflections at high carrier frequencies, degrading the linearity of the demodulated output. Bently Nevada’s matched-set calibration — where probe, cable, and driver are calibrated as a system — ensures the sensitivity specification of 7.87 V/mm is maintained across the full linear range without field recalibration when the assembly is replaced as a unit.

Redundancy Compatibility: In dual-voting machinery protection architectures (2oo3 or 1oo2D logic), two or three 330904-series transducers are mounted at 90° intervals around the shaft. The NSv output level (−18 VDC nominal) is consistent across all channels, allowing the 3300 XL monitor’s internal comparator logic to perform gap-difference arbitration without offset correction — a requirement for reliable trip/alarm discrimination in high-speed turbomachinery.

System Integration Benefits

• Direct 3300 XL NSv Monitor Compatibility: The −18 VDC output maps directly to the NSv input channel range of the 3300 XL monitor family. No jumper changes, no bias resistor modifications, and no software scaling adjustments are required during replacement.
• 3500 Rack System Interoperability: The assembly interfaces with Bently Nevada 3500/40M Proximitor I/O modules and 3500/42M Proximitor/Velomitor I/O modules, enabling integration into the 3500 rack’s deterministic 5 ms scan cycle for real-time vibration alarming.
• System 1 Software Integration: Output data feeds into Bently Nevada System 1 condition monitoring software via the 3500 rack’s Ethernet gateway, enabling trend logging, spectrum analysis, and orbit plot generation without additional signal conditioning hardware.
• API 670 Compliance Out of Box: The assembly meets all API 670 4th Edition requirements for proximity transducer systems, including sensitivity tolerance (±0.5%), temperature coefficient, and cable length specifications — eliminating the need for site-level compliance verification.
• Sub-Synchronous Instability Detection: The DC-to-10 kHz frequency response captures oil whirl (typically 0.43–0.48× running speed) and oil whip phenomena in journal-bearing machines, providing early warning of rotor dynamic instabilities before they escalate to destructive vibration levels.
• Axial Position and Differential Expansion Measurement: Beyond radial vibration, the same transducer assembly can be configured for thrust position monitoring (axial gap measurement) and differential expansion measurement on multi-stage steam turbines, reducing the number of distinct spare part types required in a plant’s MRO inventory.
• Minimal Downtime Replacement: The matched-set design allows field replacement without recalibration of the monitor. Maintenance personnel replace the probe-cable-driver assembly as a single unit, restore the gap to the specified 1.0–1.5 mm operating range, and return the machine to service — a procedure executable within a standard 4-hour maintenance window.
• Diagnostic Transparency via Gap Voltage Monitoring: The raw DC output voltage is accessible at the driver output connector, allowing maintenance technicians to verify probe gap with a standard voltmeter (−18 VDC ± 2 V at correct gap) without removing the probe from the bearing housing — a non-intrusive diagnostic step that confirms transducer health during online operation.

Quality Assurance & Global Logistics

Every 330904-00-16-50-02-00 unit dispatched from our Xiamen, China facility is a genuine Bently Nevada OEM assembly sourced through verified distribution and authenticated surplus channels. Prior to shipment, each unit undergoes a structured inspection protocol: visual examination of probe tip, connector, and cable jacket integrity; coaxial connector continuity and insulation resistance check; and label verification against Bently Nevada OEM marking specifications including font, part number format, and date code structure. Units that do not pass all inspection criteria are quarantined and not offered for sale.

A 12-month operational warranty covers manufacturing defects from the date of shipment. Certificate of conformance documentation is available on request. NIST-traceable calibration reports can be arranged for applications requiring documented metrology traceability.

Logistics from Xiamen are executed via DHL Express, FedEx International Priority, and UPS Worldwide Expedited, with typical transit times of 3–5 business days to Europe, North America, and Southeast Asia. Sea freight consolidation is available for bulk orders exceeding 20 units. Commercial invoice, packing list, and HS code documentation are prepared for all shipments to facilitate customs clearance. Same-day or next-business-day dispatch is standard for in-stock units confirmed at time of order.

Contact Information

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