21504-12-28-10-02 | Bently Nevada 8 mm Probe Proximity Vibration

Solving Vibration Monitoring Challenges with the 21504-12-28-10-02

When unplanned downtime threatens production targets, the 21504-12-28-10-02 from Bently Nevada provides reliable proximity vibration measurement. This 8 mm probe transducer system captures shaft vibration data with a calibrated range of 80 mils (2.0 mm), starting at approximately 10 mils (0.25 mm) from the probe face. Engineers trust this model for consistent performance in rotating machinery protection.

Key Features & Technical Specs of the 21504-12-28-10-02

• Scale Factor: 200 mV/mil (7.87 V/mm), ±4% when calibrated as a system.
• 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.
• Linearity: Within 0.8 mils (0.02 mm) of a 200 mV/mil straight line if calibrated as a system.
• Temperature Sensitivity: Typically -3% change in scale factor at +150°F (+65°C) at 50 mils gap (1.27 mm).
• Operating Temperature (Probe): -30°F to +350°F (-34°C to +177°C).
• System Weight: 1.3 lbs (0.59 kg).

One standout feature is the 200 mV/mil scale factor, which allows precise gap voltage monitoring for early detection of shaft vibration changes, reducing false alarms.

Real-World Applications

In oil and gas refineries, the 21504-12-28-10-02 monitors centrifugal compressor shaft vibration. Its corrosion resistance to air, water, lube oil, and chemicals like ammonium hydroxide ensures reliable operation in harsh environments. Similarly, power generation facilities use this probe for turbine vibration monitoring, benefiting from its wide frequency response up to 10 kHz.

Installation Guide

Mount the 8 mm probe with 3/8-24 threads into a standard mounting hole. Ensure the unthreaded length of 120 mm and overall case length of 2.8 inches match the installation clearance. Connect the miniature male coaxial connector (option 02) to the proximitor. Verify the total cable length of 1.0 metre (39 inches) with tolerance of +0.25 m, -0.10 m.

Routine Care & Reliability

Periodically inspect the probe tip and cable for physical damage. The system operates in relative humidity up to 95% noncondensing. For 8 mm probes, direct contact with common industrial fluids does not affect operation. Regular calibration checks maintain the ±4% scale factor accuracy, extending service life and reducing replacement costs.

Compatibility & Integration

The 21504-12-28-10-02 integrates with Bently Nevada 7200 Proximity Transducer Systems. It works with standard monitoring racks and software for continuous vibration analysis. No additional communication protocols are specified; refer to the system manual for interface details.

Troubleshooting Common Issues

If output voltage drifts, check the power supply for stable -17.5 Vdc to -26 Vdc. Verify the probe gap is within the calibrated range (10 to 80 mils). For frequency response deviations, inspect cable connections for intermittent shorts. Temperature sensitivity of -3% at 150°F may require compensation in high-heat applications.

FAQs about the 21504-12-28-10-02

Q: What is the scale factor of the 21504-12-28-10-02?

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

Q: What is the operating temperature range for the probe?

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

Q: What power supply does the 21504-12-28-10-02 require?

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

Q: What is the calibrated range of this proximity probe?

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 frequency response of the 21504-12-28-10-02?

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

Product Support & Availability

The 21504-12-28-10-02 is available in new and original factory packing from Petro Auto Tech. Please verify current lifecycle status and availability before ordering.