21500-00-12-10-02 | Bently Nevada 200 mV/mil Proximity Probe

Solving Vibration Monitoring Challenges with the 21500-00-12-10-02

When rotating machinery demands precise vibration measurement under harsh conditions, the 21500-00-12-10-02 from Bently Nevada provides a proven solution. This proximity probe offers a calibrated range of 80 mils (2.0 mm) and a scale factor of 200 mV/mil (7.87 V/mm), ensuring accurate data for predictive maintenance. Engineers rely on this sensor to detect early signs of bearing wear, shaft misalignment, and unbalance before they cause costly downtime.

Key Features and Technical Specifications

• Calibrated Range: 80 mils (2.0 mm) starting at approximately 10 mils (0.25 mm) from the probe face.
• Scale Factor: 200 mV/mil (7.87 V/mm) with ±4% accuracy when calibrated as a system.
• Linearity: Within 0.8 mils (0.02 mm) of a 200 mV/mil straight line when calibrated as a system.
• Frequency Response: 0 to 10 kHz (0 to 600,000 cpm) with -5% at 10 kHz.
• Power Input: -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).

The standout spec is the 200 mV/mil scale factor, which provides high sensitivity for detecting subtle shaft vibrations. This feature makes the 21500-00-12-10-02 ideal for critical rotating equipment where early fault detection is paramount.

Real-World Applications

This proximity probe excels in turbomachinery, compressors, and large pumps where shaft vibration monitoring is essential. For example, in a steam turbine application, the sensor's 0 to 10 kHz frequency response captures both low-speed run-up vibrations and high-speed operational data. Additionally, its corrosion resistance (for 8 mm probes) ensures reliable performance in environments with lube oil, water, or mild chemical exposure.

Installation and Setup Guidance

Mount the probe with the 1/4-28 thread into a rigid bracket or housing, ensuring the tip is positioned within the calibrated range. The unthreaded length option of 0 mm and overall case length of 1.2 in simplify alignment. Connect the miniature male coaxial connector to the proximitor using the 1.0 metre (39 inches) cable. Verify the power supply delivers -17.5 Vdc to -26 Vdc at 12 mA maximum before energizing the system.

Maintenance and Reliability

Regularly inspect the probe tip and cable for physical damage or contamination. The system operates reliably in up to 95% noncondensing relative humidity. For long-term accuracy, recalibrate the sensor as a system per Bently Nevada guidelines. This proactive approach minimizes unplanned downtime and extends equipment life.

Compatibility and Integration

The 21500-00-12-10-02 integrates with Bently Nevada 7200 Proximity Transducer Systems (model 21504). It works seamlessly with standard monitoring racks and data acquisition platforms that accept 200 mV/mil inputs. For system-level calibration, pair the probe with a compatible proximitor and extension cable to achieve the specified ±4% accuracy.

Troubleshooting Common Issues

If output readings drift, check the gap voltage and ensure the probe tip is within the calibrated range (10 to 90 mils). Verify the power supply voltage is stable between -17.5 Vdc and -26 Vdc. For intermittent signals, inspect the coaxial connector for loose connections or cable damage. Always refer to the official Bently Nevada manual for detailed diagnostics.

Frequently Asked Questions

What is the calibrated range of the 21500-00-12-10-02?

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

What is the scale factor of this proximity probe?

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

What power supply does the 21500-00-12-10-02 require?

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

What is the frequency response of the sensor?

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

What is the operating temperature range for the probe and cable?

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

Product Support and Availability

The Bently Nevada 21500-00-12-10-02 is available in stock at Petro Auto Tech. Contact our team for pricing and lead time. We provide factory-sealed units with a 12-month warranty.