Product Overview
The Bently Nevada 330191-40-75-50-CN is a 3300 XL 8 mm ETR proximity probe designed for precise vibration and position monitoring in critical rotating machinery. This model features a 3/8-24 UNF thread without armor, a 4.0-inch unthreaded length, 7.5-inch overall case length, and a 5.0-meter (16.4 ft) total probe length. It incorporates patented TipLoc molding and CableLoc pull strength of 330 N (75 lbf) to prevent common failure modes such as probe tip separation and cable breakage. An optional FluidLoc cable prevents oil leaks through the cable interior, enhancing reliability in harsh environments.
Technical Specifications
| Parameter |
Value |
| Power Requirement |
-17.5 Vdc to -26 Vdc (nonincendive), -23 Vdc to -26 Vdc with barriers; 12 mA max consumption |
| Supply Sensitivity |
Less than 2 mV change per volt change in input voltage |
| Output Resistance |
50 Ω |
| Probe DC Resistance (5.0 m) |
8.73 ± 0.50 Ω |
| Probe Tip Material |
Polyphenylene sulfide (PPS) |
| Probe Case Material |
AISI 303 or 304 stainless steel |
| Cable Type |
75 Ω triaxial, FEP insulated (standard) or PFA (extended temperature) |
| Maximum Connector Torque |
0.565 N·m (5 in·lbf) |
| Probe Weight |
323 g/m (11.4 oz) |
| Temperature Range (Probe Only) |
-55°C to +232°C (T1 classification) |
All specifications are derived from the product datasheet. The 330191-40-75-50-CN is designed for use with the 5-meter Proximitor sensor only.
Failure Mode Analysis & Enhanced Reliability
Traditional proximity probes often suffer from tip detachment, cable fatigue, and oil ingress. The Bently Nevada 330191-40-75-50-CN addresses these issues through several patented innovations. The TipLoc molding method creates a robust bond between the probe tip and body, eliminating separation under vibration. The CableLoc design provides 330 N (75 lbf) tensile strength at the probe case-to-lead and 270 N (60 lbf) at the connectors, reducing cable pull-out risks. For applications with oil leakage, the FluidLoc optional cable prevents liquid migration through the cable interior. The 8 mm probe diameter provides thicker PPS encapsulation and a stronger stainless steel case, offering superior resistance to physical abuse compared to smaller probes.
Industry Applications
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Steam Turbines & Compressors: The 330191-40-75-50-CN provides reliable shaft vibration monitoring in high-temperature environments (up to 232°C ambient). Its robust construction withstands continuous exposure to heat and contaminants.
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Pumps & Fans: The FluidLoc cable option makes this probe ideal for applications where oil or water leakage could compromise measurement integrity, such as in lubrication systems or wet process areas.
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Generators & Gearboxes: The extended temperature range cable (PFA insulated) allows operation in extreme conditions, ensuring uninterrupted data collection in critical power generation assets.
By choosing the Bently Nevada 330191-40-75-50-CN, operators reduce unexpected downtime caused by sensor failures, directly improving overall equipment effectiveness.
Installation & Setup Guidance
Mount the 330191-40-75-50-CN using the 3/8-24 UNF thread with a maximum thread engagement of 0.563 inches. Apply the Viton O-ring (pre-installed) to seal differential pressure between probe tip and case. Tighten connectors to no more than 0.565 N·m to avoid damage. For 5-meter systems, connect directly to the 5-meter Proximitor sensor — no extension cable is needed. Ensure power supply meets the -17.5 Vdc to -26 Vdc requirement (or -23 Vdc to -26 Vdc with barriers). Avoid operating at voltages more positive than -23.5 Vdc to maintain full linear range.
Maintenance & Reliability
Inspect probe cables periodically for wear, especially at stress points near connectors. The standard FEP insulated cable is rated for general environments; use the PFA option for higher temperatures. Verify thread engagement and O-ring condition during each overhaul. The probe is not pressure tested prior to shipment, so test seals during commissioning if required. With proper installation, the 330191-40-75-50-CN delivers long service life with minimal maintenance, contributing to lower total cost of ownership.
Selection Guide & Purchasing Advice
Verify that the total probe length (5.0 meters) matches your application requirements — this model is intended for use with the matching Proximitor sensor only. The Country Specific Approval (CN) option ensures compliance with local regulations. For reliable sourcing, PLC Source PRO stocks this Bently Nevada 330191-40-75-50-CN as new and original in factory packing with a 12-month warranty. Confirm thread type and cable options before ordering.