When Vibration Data Has to Be Right the First Time
A turbine train on a remote gas compression skid starts showing erratic radial vibration readings. The maintenance team suspects the probe, but the real problem is the environment: heat, oil mist, and a cable run that crosses a wash-down zone. The replacement has to fit the same 1/2-14 NPT mounting thread, reach the same 2.0 m system length, and carry the hazardous-area approvals the site already documents. That is exactly the job the 173688-01-20-12-05 is built for.
This Bently Nevada 3300 XL 8 mm proximity probe is a direct replacement for radial vibration and position measurement on rotating machinery. It combines a polyphenylene sulfide (PPS) probe tip with an AISI 303 or 304 stainless steel case, so it stands up to the chemical and thermal load of oil and gas service. The miniature ClickLoc coaxial connector with FluidLoc cable option keeps the signal path sealed where moisture ingress is a real risk.
Key Parameters That Drive the Selection
| Specification | Value |
|---|---|
| Mounting Thread | 1/2-14 NPT |
| Unthreaded Length | 0.1 in |
| Overall Case Length | 2.0 in |
| System Length | 2.0 m (6.6 ft) |
| Connector / Cable | Miniature ClickLoc coaxial, FluidLoc cable |
| Agency Approvals | CSA, ATEX, IECEx |
| Probe Tip Material | Polyphenylene sulfide (PPS) |
| Probe Case Material | AISI 303 or 304 stainless steel |
| Weight | 0.323 kg |
Three specs matter most in practice. The 1/2-14 NPT thread matches the standard mounting provision on most 3300 XL installations, so the probe drops into existing hardware without an adapter. The 2.0 m system length sets the total cable run from probe tip to extension cable, and getting it wrong changes the calibrated response. The FluidLoc cable option adds a sealed cable construction for wet or wash-down areas, though Bently Nevada notes it is not necessary on the vast majority of 330105 and 330106 installations because the probe sleeve already provides protection. Review the application before specifying FluidLoc.
Where This Probe Fits
In oil and gas, this probe typically monitors compressor and pump shafts where a trip on false vibration data costs production. The CSA, ATEX, and IECEx approvals let it go into classified areas without a separate approval project. In power generation, the same probe supports steam and gas turbine radial vibration monitoring, where the PPS tip and stainless case resist long-term exposure to hot lube oil. Industrial automation users choose it for continuous position feedback on high-value rotating assets, where a 0.323 kg probe with a sealed connector simplifies the cable routing.
Installation and Maintenance Notes
Mount the probe through the 1/2-14 NPT threaded port and confirm the unthreaded length of 0.1 in seats correctly against the machine housing. Keep the overall case length of 2.0 in clear of nearby hardware. Route the FluidLoc cable away from high-temperature sources and sharp edges, and secure it so vibration does not fatigue the connector. During planned outages, inspect the probe tip for deposits, check the connector for moisture, and verify the cable jacket. Follow the manufacturer’s safety manual for all work in hazardous areas. For spares when you need them, Oil AutoTech offers fast dispatch, worldwide.
Verify Before You Order
Confirm the system length, connector type, and agency approval option match your existing installation. Please verify current lifecycle status and availability with Oil AutoTech before ordering. Contact Oil AutoTech today for pricing and availability.
