Bently Nevada 3300 XL Proximity Probe 330850-51-CN

Overview

The Bently Nevada 330850-51-CN is a 3300 XL eddy-current proximity probe used to measure radial shaft vibration, axial position and eccentricity on rotating machinery. It is part of the 3300 XL proximity transducer system, operating with a matching 3300 XL 8 mm Proximitor module, and is supplied as a genuine Bently Nevada spare for machinery protection and condition monitoring installations. The 3300 XL system is a mature, globally deployed platform that has been the API 670 machinery protection standard across power generation, oil and gas and petrochemical industries for decades.

The 3300 XL platform supports a complete family of probes, extension cables and Proximitors, and the 330850 series is one of the established probe families within it. The 330850-51-CN is matched with a 3300 XL 8 mm Proximitor, and the whole set is documented with the standard 3300 XL sensitivity of 7.87 V/mm (200 mV/mil). The probe assembly is manufactured in the United States, and the cable is terminated with the standard 3300 XL connector so the same extension cable and Proximitor spare stock covers machines across the plant.

Engineering and Design

The probe tip contains the sensing coil of the eddy-current transducer. When the shaft approaches the tip, eddy currents in the shaft surface reduce the oscillator amplitude, and the Proximitor converts this change into a DC voltage proportional to the gap. This gives a non-contact measurement that does not wear and responds to both radial vibration and slow axial movement, making the same probe suitable for eccentricity and position measurement with the appropriate monitor.

The 330850-51-CN probe is installed through a tapped hole in the machine casing and gapped to the required static voltage using the Proximitor readback. The cable is routed to the junction box, where the extension cable connects to the Proximitor input. Because the 3300 XL system is standardised, the probe, extension cable and Proximitor must be matched to the configured system length; Seven Star verifies the combination before supply. The US-built probe assembly weighs approximately 640 g with its cable.

The probe is installed in the casing with the tip gapped to the static voltage specified for the machine. The 3300 XL system is matched by length: the probe, extension cable and Proximitor are selected so their lengths add to the system length configured for the machine, and spare components purchased separately must carry matching length options. During shutdown maintenance the probe tip is inspected for deposits, the connector joints are checked for moisture ingress and the housing threads are cleaned and greased. Because the same 3300 XL platform is used across the plant, holding a small stock of matched probe and Proximitor sets shortens the repair time when a transducer fails between shutdowns.

Key Features

• 3300 XL eddy-current proximity probe
• Measures radial vibration, axial position and eccentricity
• Non-contact measurement, no sensing element wear
• Operates with 3300 XL 8 mm Proximitor module
• API 670 machinery protection standard platform
• Matched probe, extension cable and Proximitor system
• Verified build with complete part number

Applications

The 330850 series is applied to steam and gas turbines, centrifugal compressors, large pumps, generators and motors where radial vibration, thrust position and eccentricity must be monitored continuously. The probe is used in new machine installation and as a direct replacement in existing 3300 XL transducer systems.

Specifications

Why Seven Star LLC

Seven Star LLC supplies genuine Bently Nevada 3300 XL probes and transducer components to rotating equipment programmes across Oman and the GCC. Every probe is verified against the complete part number and matched to the correct extension cable and Proximitor before your order is confirmed, and our team confirms the system length for your machine.

Why API 670 Matters

API 670 is the petroleum and chemical industry’s own specification for machinery protection systems, covering the mechanical configuration, linear measurement range, accuracy, and temperature stability required of vibration and position transducers on critical turbomachinery. A transducer system built to API 670 gives plant reliability engineers a common, auditable performance baseline across different machine trains and different vendors’ monitoring racks, which is one of the reasons the 3300 XL platform remains the de facto standard specified on new turbine, compressor, and pump trains across GCC oil & gas, petrochemical, and power generation projects even decades after its original introduction.

System Matching and Field Practice

Because the 3300 XL platform is a matched-length system, replacing a single failed component in the field — probe, extension cable, or Proximitor — requires confirming that the replacement’s length designation is compatible with the lengths already installed elsewhere in that specific measurement loop; mixing lengths from different system configurations can shift the calibrated scale factor and produce an incorrect reading even though every individual component is genuine. This is why Seven Star LLC always asks for the full part number of every component already in service on the machine, not just the failed part, before confirming a replacement quotation.

Why Seven Star LLC

Seven Star LLC supplies genuine Bently Nevada (Baker Hughes) 3300 XL transducer components to power generation, oil & gas, and petrochemical customers across Oman and the wider GCC, and cross-checks every full part number against Bently Nevada’s own ordering documentation before confirming a quotation, flagging any part-number detail that cannot be independently verified rather than assuming it is correct.

Request a Quote for Bently Nevada 3300 XL Proximity Probe 330850-51-CN

Submit a formal inquiry through our RFQ page with the probe part number 330850-51-CN, your Proximitor part number and the system length. We will confirm the correct 3300 XL transducer configuration and respond with a formal quotation. | Inquiry Form

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