Bently Nevada 330906-02-12-05-02-CN 3300 NSv Reverse Mount Probe – Compact eddy-current sensing for tight spaces and small shaft targets

The Bently Nevada 330906 3300 NSv Reverse Mount Probe is built for machines where space is tight and cable protection matters. From my experience, teams choose this probe when they need reliable shaft vibration and position signals on smaller rotors, or when a traditional front-mount just won’t fit. It pairs with the 3300 NSv Proximitor Sensor to deliver clean, stable measurements in locations that are notoriously hard to reach—think small compressors, gearboxes, and high-speed auxiliary drives.

Company’s Order Placement Process and Guarantees

• Warranty: 365 days
• Delivery: 1 week for in-stock items; no more than one month at the latest
• Payment: 50% advance payment, full payment before delivery
• Express delivery: FedEx, UPS, DHL
• Packaging: Anti-static and vibration-safe packing suitable for international transit

Key Features

• Reverse-mount design – Installs from the inside of the machine case for better cable protection and a clean external profile. You might notice fewer cable rub issues in cramped skids.
• NSv (narrow side-view) form factor – Optimized for limited radial clearance and smaller shaft diameters where a short linear range is acceptable and desirable.
• Stable eddy-current measurement – Provides precise gap and vibration data when used with the 3300 NSv Proximitor Sensor, typically with the familiar −200 mV/mil scale factor at the monitor.
• System compatibility – Works with Bently Nevada monitoring systems (e.g., 3500 series), so drop-in upgrades are straightforward in many cases.
• Industrial build – Probe materials and construction suitable for harsh, oily environments typically found around rotating equipment.
• Flexible lengths and threads – Available in common thread types and system lengths that align with standard Bently Nevada installation practices.

Technical Specifications

Brand / Model	Bently Nevada 330906-02-12-05-02-CN (3300 NSv Reverse Mount Probe)
HS Code	903180 (Measuring/Checking Instruments—Proximity/Vibration sensors)
Power Requirements	Passive probe; powered via 3300 NSv Proximitor Sensor (no direct power to the probe)
Signal Input/Output Types	Eddy-current proximity measurement; system output is a voltage proportional to gap/vibration via Proximitor (nominal −200 mV/mil typical)
Communication Interfaces	None (analog proximity system via Proximitor)
Installation Method	Reverse-mount into a prepared bore; set gap with feeler gauge/fixture; lock with jam nut per Bently Nevada practice
Dimensions & Weight	Compact reverse-mount body with slim sensing tip; overall length and thread type depend on ordered options
Compatible Components	330910 3300 NSv Proximitor Sensor; 330901 Extension Cable (system lengths typically 5 m / 7 m / 9 m)

Application Fields

This probe is used where machine envelopes are tight and measurement points are tucked away. Typical applications include:

• Small and medium centrifugal compressors (limited radial access near seals and bearings)
• Gearboxes and high-speed auxiliary drives (where standard 8 mm probes are too large)
• Pumps, fans, and blowers with compact bearing housings
• Steam and gas turbine auxiliaries, including turning gear monitors

A maintenance supervisor told us their cable damage incidents dropped after moving to reverse-mount on a compact gearbox. That kind of field feedback seems to be common with NSv setups in congested skids.

Advantages & Value

• Reliability – Reverse routing helps protect the cable run and reduces accidental snagging during maintenance.
• Compatibility – Works within the Bently Nevada 3300 NSv chain, integrating smoothly to 3500/3701 monitors already on many sites.
• Cost savings – In many cases a direct replacement that avoids re-machining the case or changing rack configurations.
• Support – Clear identification, traceability, and technical support for system setup, including gap and linear range guidance.

Installation & Maintenance

• Mounting: Prepare the bore and counterbore to the specified thread/seat; insert from the inside (reverse mount) and lock with the jam nut. Maintain the recommended standoff to the target.
• Cabinet & wiring: Route the extension cable away from high-voltage and VFD cables; maintain bend radius; ground the Proximitor and cabinet per site standards (EN/NEC).
• Gap setting: Set cold gap using a feeler gauge or target fixture; verify mid-range on the monitor during commissioning.
• Ventilation: Place the Proximitor in a ventilated panel; avoid hot zones that could drift the electronics.
• Routine care: Periodically inspect for rub marks, loose hardware, or oil ingress; clean the sensing area; verify bias voltage and scale factor during planned outages.
• Firmware/monitor checks: When tied to 3500/3701 monitors, keep configuration backups and confirm alarm setpoints after any maintenance.

Quality & Certifications

• Manufacturer quality system: ISO 9001
• Conformity: CE and RoHS compliance are typically available for 3300 NSv system components
• Warranty: 365 days from shipment

Recommended Supporting Components

• Bently Nevada 330910 – 3300 NSv Proximitor Sensor (drives the probe and conditions the signal to the monitor)
• Bently Nevada 330901 – Extension Cable (choose length to match your total system length and conduit plan)
• Mounting hardware – Jam nut and appropriate thread adapters where required

One thing I appreciate is how predictable the NSv system is once the mechanics are correct—good gap, clean routing, and it just runs. If you want us to verify the code “330906-02-12-05-02-CN” against your installed thread type and system length, send a photo of the nameplate or your existing BOM and we’ll cross-check before shipping.