21504-00-28-10-02 | Bently Nevada 8 mm Proximity Probe Vibration Transducer

Introduction to the Bently Nevada 21504-00-28-10-02

When reliable vibration monitoring is critical, the 21504-00-28-10-02 from Bently Nevada provides accurate, real-time data. This 8 mm proximity probe is part of the 7200 series, designed for industrial machinery protection. It measures shaft vibration and position with a calibrated range of 80 mils (2.0 mm) and a scale factor of 200 mV/mil (7.87 V/mm).

Key Features and Technical Specifications

• Power input: -17.5 Vdc to -26 Vdc at 12 mA maximum consumption.
• Calibrated range: 80 mils (2.0 mm), beginning at approximately 10 mils (0.25 mm) from the 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 (system calibrated), or within 2.3 mils (0.06 mm) including interchangeability errors.
• Frequency response: 0 to 10 kHz (0 to 600,000 cpm); -5% at 10 kHz.
• Temperature sensitivity: Typically -3% change in scale factor at +150°F (+65°C) at 50 mils gap (1.27 mm).
• Operating temperature: Proximitor -60°F to +212°F (-51°C to +100°C); probe and cable -30°F to +350°F (-34°C to +177°C).
• Relative humidity: Up to 95%, noncondensing.
• System weight: 1.3 lbs (0.59 kg).
• Probe diameter: 8 mm, with 3/8-24 threads and standard case.

Performance Insight: Scale Factor Accuracy

The 21504-00-28-10-02 offers a scale factor of 200 mV/mil with ±4% accuracy when calibrated as a system. This precision ensures reliable vibration measurements, reducing false alarms and improving machine protection. Even with interchangeability errors, linearity remains within 2.3 mils, maintaining consistent performance across multiple probes.

Applications and Use Cases

Engineers use the 21504-00-28-10-02 in rotating machinery such as turbines, compressors, and pumps. It monitors shaft vibration and position, helping prevent unplanned downtime. The probe resists direct contact with air, water, lube oil, ammonium hydroxide, sulfuric acid (10%), MEK, and DMF, making it suitable for harsh environments.

Installation and Setup

Proper installation ensures accurate readings. Mount the probe with 3/8-24 threads, maintaining a gap of approximately 10 mils (0.25 mm) from the target surface. The total cable length is 1.0 meter (39 inches) with a miniature male coaxial connector. Use the specified unthreaded length of 0 mm and overall case length of 2.8 inches.

Maintenance and Reliability

Regular inspection of the probe and cable helps maintain performance. The system operates reliably in temperatures from -60°F to +350°F (-51°C to +177°C) and humidity up to 95% noncondensing. For long-term accuracy, verify the scale factor periodically using a calibrated target.

Comparison with Similar Proximity Probes

Compared to other 8 mm probes, the 21504-00-28-10-02 offers a wider calibrated range (80 mils vs. typical 40 mils) and a higher frequency response (10 kHz). Its linearity of 0.8 mils (system calibrated) outperforms many standard probes, which often exceed 1.5 mils. The corrosion resistance to chemicals like MEK and DMF also sets it apart for industrial use.

Frequently Asked Questions

What is the power requirement for the 21504-00-28-10-02?

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

What is the calibrated range of this probe?

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

What is the frequency response of the 21504-00-28-10-02?

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

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.

What is the total cable length?

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

Product Support and Availability

The Bently Nevada 21504-00-28-10-02 is available as new and original in factory packing from Petro Auto Tech. Please verify current lifecycle status and availability before ordering.