Bently Nevada 21504-04-12-05-02 Proximity Probe 8mm

Bently Nevada 21504-04-12-05-02 7200 Proximity Transducer System

Product Introduction

The Bently Nevada 21504-04-12-05-02 is a factory-new proximity vibration probe from the trusted 7200 series. It is specifically engineered for non-contact displacement and vibration measurement on rotating machinery. This model features an 8 mm tip diameter and a standard 3/8-24 thread configuration. Its overall case length is 120mm, with a 40mm unthreaded tip section. The system includes a 0.5-meter integral cable terminated with a miniature male coaxial connector. This sensor provides reliable performance over a calibrated range of 80 mils (2.0 mm), beginning at just 10 mils from the probe face. It is an ideal choice for monitoring shaft vibration, thrust position, and eccentricity in turbines, compressors, and pumps.

Technical Specifications

The Bently Nevada 21504 operates on a DC power input ranging from -17.5 Vdc to -26 Vdc, with a maximum current consumption of 12 mA. Its output is calibrated to a standard scale factor of 200 mV/mil (7.87 V/mm) with a system accuracy of ±4%. The linearity is within 0.8 mils (0.02 mm) when calibrated as a complete system. Frequency response is flat from 0 to 10 kHz (0 to 600,000 cpm), with a -5% deviation at the upper limit. The temperature sensitivity typically shows a -3% change in scale factor at +150°F (+65°C) when measured at a 50-mil gap. Furthermore, the system offers interchangeability within ±9.5%, maintaining linearity within 2.3 mils. This high level of precision ensures the 21504-04-12-05-02 delivers consistent data for predictive maintenance and machine protection.

Mechanical & Environmental Limits

This proximity probe system is built for harsh industrial environments. The Proximitor can operate in temperatures from -60°F to +212°F (-51°C to +100°C). Meanwhile, the probe and extension cable withstand temperatures from -30°F to +350°F (-34°C to +177°C). It is also rated for up to 95% relative humidity, non-condensing. Additionally, the 8 mm probe resists direct contact with air, water, lube oil, ammonium hydroxide, 10% sulfuric acid, MEK, and DMF. This robust construction makes the Bently Nevada 21504 suitable for use in chemical plants, oil refineries, and power generation facilities. The total system weight is only 1.3 lbs (0.59 kg), making it lightweight and easy to handle during installation.

Installation Guidelines

Before installing the 21504-04-12-05-02, ensure the target surface is clean and within the specified runout tolerances. First, mount the probe using the 3/8-24 thread, ensuring the unthreaded length of 40mm provides the correct standoff distance. Next, connect the miniature coaxial connector to the extension cable or directly to the Proximitor. The total length option of 0.5 meters (with a tolerance of +0.13m, -0.05m) offers flexibility for routing. For optimal accuracy, perform a system calibration using a certified target and micrometer. After that, secure all connections to prevent loosening due to vibration. Finally, verify the output voltage at the initial gap to confirm the probe is operating within its linear range. Always refer to the factory manual for detailed mounting torque and gap voltage settings.

Packaging List

• 1 x Bently Nevada 21504-04-12-05-02 Proximity Probe with integral cable

• 1 x Miniature male coaxial connector (pre-installed)

• 1 x Installation instruction sheet

• 1 x Factory calibration tag

Note: The Proximitor is sold separately unless specified as a complete system.

Shipping Information

All orders are dispatched via FedEx, UPS, or DHL with full tracking. Delivery times vary by destination, but standard express shipping typically takes 3–5 business days.

Frequently Asked Questions (FAQ)

1. What is the calibrated range of the 21504-04-12-05-02?
The Bently Nevada 21504-04-12-05-02 has a calibrated range of 80 mils (2.0 mm), starting at approximately 10 mils from the probe face.

2. Can this probe be used in a high-humidity environment?
Yes, this 8 mm probe operates reliably in relative humidity up to 95% non-condensing. Its corrosion resistance also covers many chemicals, including water and lube oil.

3. What is the scale factor and its accuracy?
The scale factor is 200 mV/mil (7.87 V/mm). When calibrated as a system, accuracy is within ±4%. Including interchangeability errors, it remains within ±9.5%.

4. Does the 0.5-meter cable length have a tolerance?
Yes, the total length option 05 is 0.5 metre with a tolerance of +0.13 metre and -0.05 metre (+5 inches, -2 inches).

5. What is the frequency response of this transducer?
The 21504 model offers a frequency response from 0 to 10 kHz (0 to 600,000 cpm), with a -5% deviation at 10 kHz. This suits most high-speed rotating machinery.