21505-00-20-10-02 | Bently Nevada 8 mm Proximity Probe

Introduction: The 21505-00-20-10-02 in Action

When rotating machinery begins to vibrate unexpectedly, the 21505-00-20-10-02 from Bently Nevada helps you detect the problem early. This 8 mm proximity probe is engineered for continuous vibration and position monitoring in critical industrial environments. With a calibrated range of 80 mils (2.0 mm) and a scale factor of 200 mV/mil, it provides reliable data for condition monitoring systems.

Part of the 7200 proximity transducer system, this probe is designed to work with Bently Nevada monitors. Its rugged construction and stainless steel lead armor make it suitable for harsh conditions. Whether you are monitoring turbines, compressors, or pumps, the 21505-00-20-10-02 delivers the accuracy you need.

Key Features and Technical Specifications

• Model: 21505-00-20-10-02 – Bently Nevada 7200 proximity probe
• Diameter: 8 mm probe tip
• Total Length: 1.0 metre (39 inches), with tolerance of +0.25 m / -0.10 m
• Power: -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 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 when calibrated as a system
• Frequency Response: 0 to 10 kHz (0 to 600,000 cpm)
• 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; Probe and extension cable: -30°F to +350°F
• Relative Humidity: Up to 95%, noncondensing
• System Weight: 1.3 lbs (0.59 kg)

One distinctive feature is the 200 mV/mil scale factor, which offers high sensitivity for detecting small changes in vibration. This makes the probe ideal for early fault detection in rotating equipment.

Real-World Applications

In petrochemical plants, the 21505-00-20-10-02 monitors shaft vibration on large motors and pumps. By providing continuous data, it helps operators identify misalignment or bearing wear before they cause downtime.

Similarly, in power generation, this probe is used on steam turbines to track rotor vibration. Its frequency response up to 10 kHz covers most machinery vibration signatures, enabling effective condition monitoring.

Additionally, the probe's corrosion resistance to air, water, lube oil, and certain chemicals makes it suitable for harsh environments. This durability reduces the need for frequent replacements, saving both time and money.

Installation and Setup

Proper installation is critical for accurate readings. The probe features 3/8-24 threads, allowing secure mounting into standard probe holders. Ensure the probe face is positioned within the calibrated gap range, approximately 10 mils (0.25 mm) from the target surface.

Connect the probe to a compatible Bently Nevada proximitor, following the manufacturer's guidelines. The stainless steel lead armor protects the cable from mechanical damage, but avoid sharp bends during routing. After installation, verify the system calibration to ensure the scale factor and linearity meet specifications.

Maintenance and Reliability

Regular inspection of the probe and cable is recommended to ensure reliable operation. Check for any physical damage or wear, especially at connection points. Keep the probe face clean and free of debris, as contamination can affect measurement accuracy.

Because the probe is exposed to environmental factors, periodic verification of the system's performance is advised. This proactive approach helps maintain measurement integrity and extends the service life of the probe.

Compatibility and Integration

The 21505-00-20-10-02 is part of the Bently Nevada 7200 proximity transducer system. It is designed to work with Bently Nevada monitors that accept proximity probe inputs. When integrated as a system, the calibrated range and scale factor are optimized for accurate readings.

For new installations, ensure the monitor is configured to match the probe's sensitivity. This compatibility ensures seamless data acquisition and reliable condition monitoring.

Troubleshooting Common Issues

If you notice erratic readings, first check the probe gap and cable connections. A loose connection can cause signal noise. Also, verify that the probe tip is not damaged or worn.

Temperature variations can affect the scale factor. The probe's temperature sensitivity is typically -3% at +150°F, so account for this in high-temperature environments. If readings drift significantly, recalibrate the system according to Bently Nevada guidelines.

FAQ about the 21505-00-20-10-02

What is the calibrated range of the 21505-00-20-10-02?

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

What power supply does the 21505-00-20-10-02 require?

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

What is the frequency response of this probe?

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

Can the 21505-00-20-10-02 be used in high-humidity environments?

Yes, it can operate in relative humidity up to 95%, noncondensing.

Product Support and Availability

The 21505-00-20-10-02 is available from Petro Auto Tech, a trusted industrial automation parts supplier. It comes in new, original factory packing with a 12-month warranty. Contact Petro Auto Tech for current availability and ordering information.