Bently Nevada 330980-50-CN 3300 XL NSv Proximitor Sensor

Product Overview

The Bently Nevada 330980-50-CN is a high-precision Proximitor Sensor designed for the 3300 XL NSv (Narrow Side view) Transducer System. This specialized proximity sensor is engineered for machinery with restricted installation space or small target diameters, where standard 8 mm sensors are physically too large. It functions as the primary signal conditioner, generating a radio frequency (RF) signal to detect shaft vibration or position and converting the return signal into a linear -200 mV/mil voltage output. The 330980-50-CN is frequently deployed in centrifugal compressors, small steam turbines, and aero-derivative gas turbines to monitor radial vibration and axial thrust. The CN designation ensures compliance with country-specific agency approvals required for hazardous area operation in the Chinese industrial market.

Suffix Breakdown

The model number 330980-50-CN defines the specific electrical calibration and regional certification for the Proximitor:

• 330980: Base part number for the 3300 XL NSv Proximitor Sensor.

• 50: System Length Option designating 5.0 meters. This requires the combined length of the probe and extension cable to equal 5.0 meters to maintain the calibrated scale factor.

• CN: Agency Approval Option for China, facilitating legal installation in regulated hazardous industrial zones.

Technical Specifications

FAQs

What is the difference between 3300 XL and 3300 XL NSv Proximitors?

The NSv (Narrow Side view) series is specifically calibrated for targets as small as 0.25 inches (6.35 mm) in diameter. Standard 3300 XL sensors require a much larger target area to maintain linearity. The 330980-50-CN must only be used with NSv-specific probes and cables.

Can I use a 7.0m extension cable with a 5.0m Proximitor?

No. The 330980-50-CN is calibrated for a total system length of 5.0 meters. Using a 7.0m cable will cause a significant shift in the Gap Voltage and non-linearities in the vibration reading, potentially leading to false trips or missed alarms.

How do I troubleshoot a "High Vibration" reading on a new installation?

First, verify the Gap Voltage. If the Gap Voltage is within the -9 VDC to -11 VDC range but vibration is high, check for electrical noise (EMI) caused by poor shielding or proximity to high-power VFD cables. Ensure the Proximitor is electrically isolated from the mounting rail if required.

Engineering & Installation Guide

Mechanical Mounting and Isolation

The 330980-50-CN should be mounted in a weatherproof, hazardous-area-rated enclosure. To ensure signal integrity, the Proximitor base must be electrically isolated from the machine ground to prevent ground loops. Use the provided fiberglass isolation washers and mounting rail insulators. Failure to isolate the sensor often results in a "noisy" vibration signal that can interfere with DCS or PLC monitoring.

Field Wiring and Shielding Protocols

For the field wiring (from Proximitor to Monitor/DCS), use high-quality shielded twisted-pair cable. Connect the shield at the monitor end only. At the Proximitor end, the shield should be trimmed back and insulated with heat-shrink tubing to prevent accidental contact with the Proximitor case or the junction box. This "single-point ground" strategy is critical for high-fidelity TSI (Turbine Supervisory Instrumentation) data.

Connection Maintenance

The 330980-50-CN utilizes gold-plated ClickLoc connectors. These connectors are designed to be vibration-resistant but are sensitive to dirt and moisture. Always clean the coaxial connectors with a non-residue electronic cleaner before mating. Hand-tighten the connectors until they "click"—do not use pliers or excessive torque, as this will damage the internal dielectric and lead to signal attenuation.