21504-00-40-10-02 | Bently Nevada 8 mm Probe Proximity Vibration Transducer

What Makes the 21504-00-40-10-02 Essential for Vibration Monitoring?

When rotating machinery requires precise, real-time vibration measurement, the 21504-00-40-10-02 from Bently Nevada provides a reliable solution. This 8 mm probe proximity vibration transducer is part of the 7200 Proximity Transducer Systems family, engineered for continuous monitoring in demanding industrial environments. With a calibrated range of 80 mils (2.0 mm) and a scale factor of 200 mV/mil (7.87 V/mm), it delivers accurate data for predictive maintenance and machine protection.

Key Features & Technical Specs of the 21504-00-40-10-02

• Probe Diameter: 8 mm
• Calibrated Range: 80 mils (2.0 mm), beginning at approximately 10 mils (0.25 mm) from probe face
• Scale Factor: 200 mV/mil (7.87 V/mm), ±4% (system calibrated)
• Linearity: Within 0.8 mils (0.02 mm) of a 200 mV/mil straight line (system calibrated)
• Frequency Response: 0 to 10 kHz (0 to 600,000 cpm); -5% at 10 kHz
• Power Input: -17.5 Vdc to -26 Vdc at 12 mA maximum consumption
• Operating Temperature (Probe): -30°F to +350°F (-34°C to +177°C)
• Relative Humidity: To 95%, noncondensing
• System Weight: 1.3 lbs (0.59 kg)

One distinctive spec is the temperature sensitivity: typically -3% change in scale factor at +150°F (+65°C) at 50 mils gap (1.27 mm). This ensures consistent performance even in thermal variations common in turbine and compressor applications.

Industry Applications for the 21504-00-40-10-02

In petrochemical plants, power generation facilities, and heavy manufacturing, the 21504-00-40-10-02 monitors shaft vibration and position on critical rotating equipment. Its corrosion resistance for 8 mm probes—unaffected by air, water, lube oil, ammonium hydroxide, sulfuric acid (10%), MEK, or DMF—makes it suitable for harsh environments. The probe operates reliably in direct contact with these substances, reducing false readings and maintenance needs.

Installation & Setup Guidance

Proper mounting is crucial for accurate vibration data. The 21504-00-40-10-02 features 3/8-24 threads and a standard case. Ensure the probe face is positioned at the recommended initial gap of approximately 10 mils (0.25 mm) from the target surface. Use the miniature male coaxial connector (option 02) for secure signal transmission. Verify that the total cable length of 1.0 metre (39 inches) meets your routing requirements before final installation.

Maintenance & Reliability Tips

Regular inspection of the probe and cable assembly helps maintain measurement accuracy. Check for physical damage, corrosion, or loose connections. The system operates within -30°F to +350°F for the probe and extension cable, and up to 95% noncondensing humidity. For long-term reliability, follow Bently Nevada's recommended inspection intervals. The 12-month factory warranty provides additional assurance.

Compatibility & Integration

The 21504-00-40-10-02 integrates with Bently Nevada 7200 series monitors and other compatible vibration monitoring systems. Its 200 mV/mil output interfaces directly with standard data acquisition and protection relays. For system calibration, pair it with the corresponding Proximitor and extension cable to achieve ±4% accuracy over the full range.

Troubleshooting Common Issues

If readings drift or become erratic, first verify the probe gap is within the calibrated range (10 to 90 mils). Check the power supply for -17.5 Vdc to -26 Vdc at 12 mA maximum. Inspect the coaxial connector for damage or moisture ingress. For linearity errors beyond 0.8 mils (system calibrated), confirm the target surface is clean and the probe is securely mounted.

FAQ about the 21504-00-40-10-02

What is the calibrated range of the 21504-00-40-10-02?

The calibrated range is 80 mils (2.0 mm), starting at approximately 10 mils (0.25 mm) from the probe face.

What is the scale factor and accuracy?

The scale factor is 200 mV/mil (7.87 V/mm), with ±4% accuracy when calibrated as a system.

What temperature range can the probe withstand?

The probe and extension cable operate from -30°F to +350°F (-34°C to +177°C).

What power input does the 21504-00-40-10-02 require?

It requires -17.5 Vdc to -26 Vdc at 12 mA maximum consumption.

Is the probe resistant to chemicals?

Yes, for 8 mm probes, operation is not affected by direct contact with air, water, lube oil, ammonium hydroxide, sulfuric acid (10%), MEK, or DMF.

Product Support & Availability

The 21504-00-40-10-02 is available in new and original factory packaging from Petro Auto Tech. Each unit includes a 12-month factory warranty. Please verify current lifecycle status and availability with Petro Auto Tech before ordering.

Customer Case Scenario

Imagine a refinery experiencing unplanned downtime due to undetected bearing wear on a critical compressor. By installing the 21504-00-40-10-02 probe, the maintenance team gains continuous vibration data, enabling early detection of developing faults. This proactive approach reduces repair costs and extends equipment life.