Bently Nevada 330780-91-05 – Proximity Extension Cable for 3300 XL Vibration/Position Monitoring

The Bently Nevada 330780-91-05 is commonly used as a 3300 XL proximity extension cable, bridging the probe to the Proximitor sensor in rotating machinery monitoring. It’s a straightforward component, but in many cases it’s the difference between clean displacement signals and noisy, unreliable readings. One thing I appreciate is how these cables are built to maintain calibration over the full cable length, which typically means hassle-free installation and quicker startups on turbines, compressors, and large pumps.

Order Placement Process & Guarantees

Key Features

• Matched-length design – Maintains system calibration when paired with the proper probe and Proximitor, typically delivering accurate -200 mV/mil (7.87 mV/µm) displacement scaling across the total cable run.
• Robust signal integrity – Low-noise coaxial construction helps preserve gap voltage accuracy and dynamic response, even in high-EMI cabinets.
• Industrial-grade jacket – Durable insulation that, in most cases, resists oils and common plant solvents, suitable for routed runs in machinery skids.
• Proven 3300 XL ecosystem compatibility – Designed to work within Bently Nevada 3300 XL proximity systems when matched to the correct probe and Proximitor model.
• Time-saving hardware – Familiar connector hardware that speeds up routings and field replacements during outages.

Technical Specifications

Application Fields

From my experience, this model shows up a lot on critical rotating assets where continuous vibration and shaft position data are non-negotiable:

• Steam and gas turbines – shaft relative vibration and axial position monitoring
• Compressors and expanders – trend stability for proximity channels in harsh environments
• Large pumps and fans – reliable cabling for protection trips and predictive analytics
• Gearboxes – displacement monitoring at bearings and critical mesh points

A maintenance lead told us their crew swapped to the 3300 XL-matched cable set during a short outage and immediately saw steadier gap voltages, which made acceptance testing go faster than expected.

Advantages & Value

• Reliability in the loop – Stable transducer wiring reduces nuisance alarms and rework during commissioning.
• Compatibility – Pairs with 3300 XL probes and Proximitor sensors, which typically means no surprise scaling errors.
• Lower lifecycle cost – Durable jacket and connectors withstand frequent maintenance cycles and routing adjustments.
• Supportable choice – Easier for site teams to maintain spares commonality across units and sites.

Installation & Maintenance

• Cabinet & routing – Use ventilated cabinets; keep signal cables away from VFD and power lines; maintain gentle bend radius (typically ≥25 mm).
• Grounding & shielding – Follow Bently Nevada grounding practice; avoid creating ground loops between machine frame and rack.
• Connectors – Hand-tighten per spec; avoid over-torque; keep connectors clean and capped when not in use.
• Periodic checks – Visual inspection for abrasion or oil ingress; verify gap voltage and channel bias during scheduled PMs.
• Firmware & calibration – While the cable itself needs no firmware, plan periodic monitor firmware updates and validation to keep the measurement chain aligned.
• Safety – De-energize the monitor channel before disconnecting; follow site lockout/tagout procedures.

Quality & Certifications

• Manufacturer quality systems typically aligned with ISO standards
• CE and RoHS conformity for most proximity components in the 3300 XL family
• Hazardous area approvals (ATEX/IECEx) available on specific options; verify against the “-91” option details if your unit is in a classified zone
• Warranty: 365 days

Note: The 330780-91-05 designation appears to indicate a 5 m extension cable variant within the Bently Nevada 3300 XL proximity system. If you’re matching to existing probes/Proximitors or a hazardous-area installation, share your BOM and we’ll confirm connector style and approvals before shipment.