Bently Nevada 330106 Reverse Mount Non-armored Probes

The Bently Nevada 330106 is a reverse mount probe with metric M10×1 thread and without armor from the 3300 XL series 8 mm eddy current transducer system. This system is a global benchmark for condition monitoring of rotating machinery, widely used for vibration, displacement, speed, and Keyphasor measurements on turbines, compressors, fans, pumps, generators, and other critical equipment.

The 3300 XL 8 mm system is renowned for its advanced performance, high reliability, and complete interchangeability. The 330106 probe features M10×1 metric thread and is designed for reverse mounting – i.e., the probe is installed from inside the machine outward through the mounting hole, secured using the threads or a lock nut at the front of the probe body. This mounting style is particularly suited for applications with limited installation space or where the cable must exit from the inside. The probe is supplied without armor (standard FEP insulated triaxial cable), offering excellent flexibility and temperature resistance. Its metric thread design makes it perfectly compatible with equipment built to metric standards, especially in Europe, Asia, and other metric‑region machinery manufacturers and end users.

This product fully complies with the American Petroleum Institute (API) 670 Standard for mechanical configuration, linear range, accuracy, and temperature stability. All 3300 XL 8 mm system components (probes, extension cables, and Proximitor sensors) are fully interchangeable, eliminating the need for matching or bench calibration of individual components – greatly simplifying field maintenance and spare parts management.

2. System Components

A complete 3300 XL 8 mm eddy current transducer system consists of three core components, with the 330106 probe being the key sensing element:

1. 330106 3300 XL 8 mm Metric Thread Reverse Mount Probe – Directly senses the distance to the conductive surface (e.g., shaft). Its reverse mount design and M10×1 thread fit metric mounting holes and are ideal for installations from inside the machine outward.

2. 3300 XL Extension Cable – Connects the probe to the Proximitor sensor. The total system length (probe cable length + extension cable length) must match the Proximitor sensor’s rated length (e.g., 5 m or 9 m). The 330106 probe can be used with standard, armored, or FluidLoc extension cables (e.g., 330130 series).

3. 3300 XL Proximitor Sensor – Supplies a high‑frequency carrier signal to the probe, demodulates and amplifies the gap voltage. The output is a negative DC voltage proportional to the gap (typically -0 Vdc to -18 Vdc or -24 Vdc linear range) and can drive monitors or analyzers. Common model: 330180 series.

Important Notes:

• 1‑meter systems do not use an extension cable; the probe connects directly to the Proximitor.

• Factory default calibration target material is AISI 4140 steel. Calibration to other target materials is available upon request.

• The 330106 is electrically and physically identical to the imperial thread reverse mount model 330105, except for the thread specification.

• Reverse mount probes are not available with armor or connector protector options (see datasheet page 14 and Figure 15, note 4).

3. Key Features and Advantages

The 330106 probe incorporates many advanced designs from the 3300 XL series, while offering both metric threads and reverse mount convenience.

3.1 Robust Mechanical Design

• TipLoc™ Molding – Patented probe tip molding provides a robust bond between the probe tip and body, preventing loosening or rotation, significantly improving vibration and shock resistance.

• CableLoc™ Design – The cable‑to‑probe body connection uses the patented CableLoc design, with pull strength up to 330 N (75 lbf), ensuring the cable does not detach under high stress.

• Reverse Mount Configuration – The probe body has M10×1 threads near the tip. It is installed from inside the machine outward and secured with a lock nut. This avoids handling long cables outside the machine and simplifies installation in confined spaces, while allowing the probe tip to be positioned very close to the target surface.

• Metric M10×1 Thread – Thread size M10×1 conforms to international metric standards, allowing direct installation in metric mounting holes without adapters. Thread engagement characteristics are optimized for 8 mm probes.

3.2 Reliable Electrical Connection

• ClickLoc™ Gold‑Plated Connectors – Corrosion‑resistant ClickLoc connectors between probe and extension cable require only finger tightening (an audible “click” indicates full engagement). The special locking mechanism prevents loosening due to vibration, and no special tools are needed.

• Connector Protectors – Although reverse mount probes themselves do not include connector protectors (the datasheet explicitly states they are not available), users may purchase and install connector protectors on the extension cable side (e.g., accessory 40180-02) for environmental protection.

3.3 High RFI/EMI Immunity

• The 3300 XL Proximitor sensor and probe system exhibit high immunity to radio frequency and electromagnetic interference. Even when installed in fiberglass housings, nearby radio signals cause no adverse effects. The improved immunity meets European CE mark requirements without special shielded conduit or metal housings, reducing installation cost and complexity.

3.4 Easy Installation and Maintenance

• SpringLoc Terminal Strips – The Proximitor sensor’s SpringLoc terminal strips require no special tools. They provide fast, robust, vibration‑resistant wiring connections, eliminating screw‑type clamps that can loosen.

• Complete Interchangeability – 3300 XL 8 mm components (including the 330106 probe) are both electrically and physically interchangeable with non‑XL 3300 series 5 mm and 8 mm components. However, mixing XL and non‑XL components limits system performance to the non‑XL specifications.

4. Installation Considerations

1. Thread Engagement Length – For M10×1 metric threads, the maximum recommended engagement length is 5 mm (see datasheet page 8 table). Because the reverse mount probe has a case length of only 30 mm, care should be taken not to over‑tighten or engage too many threads. Bently Nevada does not replace probes damaged by excessive thread engagement.

2. Mounting Torque – The recommended mounting torque for reverse mount probes is 7.5 N·m (66 in·lbf); the maximum allowed torque is 22.6 N·m (200 in·lbf). Use a torque wrench to avoid over‑tightening.

3. Lock Nut – Optional M10×1 probe lock nut with safety wire holes (part number 04301008) is available to secure the probe.

4. Connector Protectors – Although the reverse probe itself does not include a connector protector option, it is recommended to use connector protectors at the probe‑to‑extension cable connection (available as accessory 40180-02). Silicone tape is not recommended for connections exposed to turbine oil.

5. Minimum Bend Radius – The minimum cable bend radius is 25.4 mm (1.0 in). Excessive bending may damage the internal cable structure.

6. Metric/Imperial Mixing – The 330106’s M10×1 thread cannot be used with imperial mounting holes or lock nuts. Ensure the mounting base also has M10×1 threads.

7. Reverse Mount Specifics – When installing, the probe passes from inside the machine outward. Ensure sufficient clearance for gap adjustment. The probe cable should be properly secured to avoid fatigue from vibration.

5. Typical Applications

The 330106 metric reverse mount probe is particularly suited for:

• Metric‑standard rotating machinery – Turbines, compressors, generators manufactured in Europe, Asia, etc., with M10×1 mounting holes requiring reverse mounting.

• Limited installation space – Where bearing housings are too cramped for standard forward mount probes; reverse mounting from inside saves space.

• Applications requiring the probe tip to be very close to the target – The short case length of reverse mount probes allows the tip to be positioned near the shaft.

• High cable flexibility needs – Non‑armored cable is more flexible for routing through tight or curved paths.

• Standard industrial environments without severe abrasion risk – Where cable armor is not required.

6. Comparison with Related Models