The Ultimate Guide to Bently Nevada's 3300 XL 8 mm Proximity Sensor Systems

Why Choose the 8 mm Series?

The 3300 XL 8 mm series is considered the industry benchmark for rotating machinery condition monitoring. It fully complies with API 670 and is widely used worldwide in steam turbines, compressors, pumps, and generators. Its core strengths lie in accuracy, reliability, compatibility, and ease of maintenance.

As one of the most commonly used series, the 8 mm system offers long-term, reliable operation in harsh industrial environments, making it an indispensable tool in predictive maintenance programs.

System Components

1. 3300 XL 8 mm Probe

Material: Stainless steel housing, polyphenylene sulfide (PPS) tip

Linear measurement range: ±2 mm (80 mil)

Sensitivity: 200 mV/mil (7.87 V/mm)

Temperature range: -51°C to +177°C

Features: High resolution, long-term stability, unaffected by field temperature fluctuations

2. 3300 XL 8 mm Extension Cable

Optional lengths: 1 m – 9 m

Anti-interference design: Double-shielded, suitable for high-EMI environments

Connection: ClickLoc quick-connect connector, locks out

3. 3300 XL 8 mm Proximitor Senso

Purpose: Converts eddy-current probe signals to a standard voltage output

Mounting: DIN rail or panel mount

Output signal: -200 mV/mil (relative to an AISI 4140 steel target)

Power requirement: -24 VDC (typical)

Benefits: Compatible with all Bently Nevada monitoring systems (such as the 3500 Series)

Technical Specifications at a Glance

System Benefits

Fully compliant with API 670 standards

Ensures accuracy, temperature stability, and interchangeability that meet global industry regulations.

Component Interchangeability

Probes, extension cables, and sensors are fully interchangeable, reducing inventory requirements and eliminating the need for field recalibration.

Long-Term Stability

Temperature-compensated design ensures high accuracy at high or low temperatures.

Easy Installation

ClickLoc connectors ensure a secure connection and prevent loosening due to vibration.

Wide Compatibility

Integrates seamlessly with the Bently Nevada 3500 system, monitoring software, and Keyphasor applications.

Typical Applications

Steam Turbines: Monitor radial and axial displacement to prevent shaft-stator rubbing

Compressors: Keyphasor speed detection and shaft centerline analysis

Generators: Monitor bearing health in real time to avoid unplanned downtime

Pumps and Gearboxes: High-precision vibration monitoring to extend equipment life

Why choose 8 mm instead of 5 mm or 11 mm?

• Compared to the 5 mm sensor: Offers a wider linear measurement range, suitable for a wider range of machinery applications.
• Compared to the 11 mm sensor: In standard environments, the 8 mm sensor is the universal "industry gold standard" with more mounting options.

In other words:

• If you need a stable, standardized solution for most industrial applications → Choose the 8 mm sensor.
• If installation space is limited → Choose the 5 mm sensor.
• If you need a larger displacement measurement range or hazardous area certification → Choose the 11 mm sensor.

Conclusion

The 3300 XL 8 mm sensor series is the "sensor of choice" for predictive maintenance programs.

Its combination of accuracy, reliability, and versatility has made it the global benchmark for rotating machinery health monitoring. Whether in power plants, petrochemical plants, or compressor stations, the 8 mm sensor system helps users:

• Identify equipment failures early
• Improve plant operational reliability
• Reduce maintenance costs
• Avoid costly unplanned downtime.

Choosing the 3300 XL 8 mm sensor means choosing the industry standard.

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