21504-00-08-10-02 | Bently Nevada 8 mm Probe Proximity Vibration Sensor

Introduction to the 21504-00-08-10-02 Bently Nevada Probe

When unplanned vibration threatens critical rotating machinery, the 21504-00-08-10-02 from Bently Nevada provides precise, real-time displacement measurements. This 8 mm probe proximity vibration sensor is part of the trusted 7200 Proximity Transducer Systems family, engineered for continuous monitoring in harsh industrial environments. With a calibrated range of 80 mils (2.0 mm) starting at approximately 10 mils (0.25 mm) from the probe face, it offers the sensitivity needed for early fault detection.

Key Features and Technical Specifications

• Calibrated Range: 80 mils (2.0 mm) begins at approximately 10 mils (0.25 mm) from probe face.
• Scale Factor: 200 mV/mil (7.87 V/mm), ±4% when calibrated as a system.
• Linearity: Within 0.8 mils (0.02 mm) of a 200 mV/mil straight line if calibrated as a system.
• Frequency Response: 0 to 10 kHz (0 to 600,000 cpm); -5% at 10 kHz.
• Input Power: -17.5 Vdc to -26 Vdc at 12 mA maximum consumption.
• Operating Temperature (Proximitor): -60°F to +212°F (-51°C to +100°C).
• Probe and Extension Cable Temperature: -30°F to +350°F (-34°C to +177°C).
• System Weight: 1.3 lbs (0.59 kg).
• Total Length: 1.0 metre (39 inches) tolerance: +0.25 m, -0.10 m.

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 means engineers must account for thermal drift in high-temperature applications to maintain measurement accuracy.

Applications and Use Cases

Industries rely on the 21504-00-08-10-02 for vibration monitoring of turbines, compressors, pumps, and motors. In oil and gas facilities, it helps detect shaft misalignment and bearing wear before catastrophic failure occurs. Similarly, power generation plants use this probe to track rotor dynamics and ensure operational safety. The probe's corrosion resistance to air, water, lube oil, ammonium hydroxide, sulfuric acid (10%), MEK, and DMF makes it suitable for chemical processing environments.

Installation and Setup Guidance

Proper mounting is critical for accurate readings. Install the probe so the target surface is perpendicular to the probe axis. Maintain the recommended gap range of approximately 10 to 90 mils (0.25 to 2.29 mm) from the probe face. Use the miniature male coaxial connector for secure signal transmission. Always follow the Bently Nevada 7200 system manual for wiring and calibration procedures.

Maintenance and Reliability Tips

Regularly inspect the probe tip and cable for physical damage or contamination. Verify the system's scale factor and linearity periodically using a calibration fixture. Because the probe operates in temperatures from -30°F to +350°F, ensure the cable jacket remains intact and free of cuts. Following these steps extends service life and reduces unplanned downtime.

Compatibility and Integration

The 21504-00-08-10-02 integrates with Bently Nevada 7200 series monitors and software. It is designed as a system component, typically paired with a Proximitor and extension cable. For best performance, use the probe with Bently Nevada's recommended signal conditioning modules. Refer to the official datasheet for full compatibility details.

Frequently Asked Questions

Q: What is the calibrated range of the 21504-00-08-10-02?

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

Q: What is the scale factor tolerance?

A: The scale factor is 200 mV/mil (7.87 V/mm) with ±4% tolerance when calibrated as a system, and within ±9.5% including interchangeability errors.

Q: What power supply does this probe require?

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

Q: What is the frequency response of the 21504-00-08-10-02?

A: The frequency response is 0 to 10 kHz (0 to 600,000 cpm) with -5% at 10 kHz.

Q: What is the total length of the probe cable?

A: The total length is 1.0 metre (39 inches) with a tolerance of +0.25 m, -0.10 m.

Product Support and Availability

The 21504-00-08-10-02 is available as new and original in factory packing from Petro Auto Tech. It comes with a 12-month factory warranty. Please verify current lifecycle status and availability with Petro Auto Tech before ordering.