330703-00-100-10-11-CN | Bently Nevada | 3300 XL 11 mm Proximity Probes

Technical Overview

The Bently Nevada 330703-00-100-10-11-CN is an 11 mm eddy current proximity probe designed for non-contact displacement and vibration measurement on rotating machinery. It functions as a core component of the 3300 XL 11 mm Transducer System, which also includes a matched extension cable and a 3300 XL 11 mm Proximitor Sensor. The system operates on the eddy current principle, where the Proximitor Sensor emits a high-frequency radio frequency (RF) signal through the probe and extension cable. This signal radiates from the probe tip, creating an electromagnetic field. When a conductive target, such as a machine shaft, enters this field, eddy currents are induced on its surface. These currents create a secondary magnetic field that opposes the primary field, causing a measurable change in the RF signal’s impedance. The Proximitor Sensor demodulates this signal to produce a DC voltage directly proportional to the gap between the probe tip and the target surface. This analog voltage signal is then transmitted to a monitoring system, such as the Bently Nevada 3500 series, for real-time analysis of radial vibration, axial position, and shaft speed. The 330703-00-100-10-11-CN features a robust stainless steel case and a chemically resistant Polyphenylene Sulfide (PPS) tip, ensuring reliability in harsh industrial environments.

Detailed Specifications

Operational Capabilities

The 330703-00-100-10-11-CN proximity probe is engineered for high reliability in demanding industrial applications, particularly within Oil & Gas and Power Generation sectors. Its 11 mm tip provides a larger linear measurement range and is well-suited for monitoring large shaft diameters or applications requiring a greater standoff distance. The probe’s construction ensures operational integrity across a wide temperature range, with the probe tip rated for -51 °C to +177 °C (-60 °F to +351 °F). The 3300 XL system design provides enhanced immunity to radio frequency interference (RFI/EMI), minimizing the risk of signal corruption from nearby motors, generators, or radio sources. The gold-plated ClickLoc™ connector ensures a secure, corrosion-resistant connection that prevents intermittent signals caused by vibration. When installed and maintained according to manufacturer specifications, the system demonstrates high Mean Time Between Failures (MTBF) and is a critical component for machinery protection systems (MPS) and condition monitoring programs, compliant with standards such as API 670.

Applications

• Steam and gas turbines for power generation
• Large centrifugal and reciprocating compressors in oil & gas processing
• Boiler feed water pumps and other critical pump applications
• Large electric motors and generators
• Gearboxes and other industrial rotating machinery with fluid-film bearings
• Integration into predictive maintenance and machinery protection systems (MPS)
• Axial (thrust) position and radial vibration monitoring

Technical FAQ

Q: What systems is the 330703-00-100-10-11-CN compatible with?
A: The 330703-00-100-10-11-CN probe must be used as part of a complete Bently Nevada 3300 XL 11 mm Transducer System. This requires a matching 3300 XL 11 mm Proximitor Sensor (e.g., part number 330780) and a 3300 XL 11 mm extension cable. It is not interchangeable with components from 5 mm or 8 mm transducer systems, as the scale factor and linear range are different. The complete transducer system provides a voltage output compatible with Bently Nevada monitoring systems, including the 3500 and 3300 series, as well as third-party PLCs, DCS, and data acquisition systems designed to accept a 3-wire, -24 Vdc powered eddy current probe input.

Q: What are the installation requirements?
A: Proper installation is critical for accurate measurements. The probe must be mounted perpendicular to the observed shaft surface using a rigid bracket. The target area on the shaft must be smooth (typically 0.4 to 0.8 µm / 16 to 32 µin Ra), free of chrome or other non-conductive plating, and clear of any residual magnetism or electrical runout. The probe must be gapped correctly by adjusting its distance to the shaft until the Proximitor Sensor output voltage is at the center of the linear range, typically -10.0 Vdc. The probe case locknut should be torqued to the specified value to prevent loosening. The integral cable and any extension cable should be secured to avoid strain on the connectors and routed away from high-voltage power cables to minimize interference.