21508-02-12-90-02 Bently Nevada 8mm Proximity Probe

21508-02-12-90-02 Bently Nevada 8mm Reverse Mount Proximity Probe

Product Introduction

The Bently Nevada 21508-02-12-90-02 delivers precision vibration measurement for critical rotating machinery. This non-contact eddy current transducer converts physical gap distance into a proportional voltage signal. Additionally, this sensor belongs to the renowned 7200 series and works seamlessly with Bently Nevada monitoring systems. The long 9-meter cable option suits installations where the monitor resides far from the measurement point. Moreover, its reverse mounting configuration offers distinct advantages for specific mechanical housing designs. For these reasons, the Bently Nevada 21508-02-12-90-02 provides reliable data for predictive maintenance and machine health programs.

Technical Specifications

The 21508-02-12-90-02 sensor maintains accurate and stable performance across various operating conditions. Its calibrated linear range spans 80 mils (2.0 mm), beginning at approximately 10 mils (0.25 mm) from the probe face. Furthermore, the system outputs a standard scale factor of 200 mV/mil (7.87 V/mm) , which plays a critical role in interpreting vibration amplitude. When you calibrate the system as a complete assembly, the linearity stays within 0.8 mils (0.02 mm) of an ideal straight line. Additionally, the frequency response covers a broad spectrum from 0 to 10 kHz (0 to 600,000 cpm) , with only a -5% deviation at the highest frequency. The 21508-02-12-90-02 draws a maximum current of 12 mA from a power supply between -17.5 Vdc and -26 Vdc. Users should also note that the temperature sensitivity typically changes the scale factor by -3% at +150°F (+65°C) with a 50 mil gap.

Mechanical and Environmental Features

The 21508-02-12-90-02 features a rugged 8 mm diameter case with a reverse 3/8-24 thread configuration and excludes lead armor. This reverse thread design distinguishes this particular model from standard probes. It performs reliably in harsh industrial settings, with the probe and extension cable operating between -30°F to +350°F (-34°C to +177°C) . Meanwhile, the Proximitor electronics withstand temperatures ranging from -60°F to +212°F (-51°C to +100°C) . In addition, this probe resists corrosion from air, water, lube oil, ammonium hydroxide, 10% sulfuric acid, MEK, and DMF. It also functions properly in environments with up to 95% non-condensing relative humidity.

Installation and Configuration

Installing the Bently Nevada 21508-02-12-90-02 demands careful preparation of the target surface and mounting position. First, clean the target area thoroughly and verify its conductive properties for accurate readings. Next, secure the probe firmly using its 3/8-24 reverse threads, which prevents loosening due to vibration. Set the initial gap to approximately 10 mils (0.25 mm) to enter the calibrated measurement range. Meanwhile, this model provides a total cable length of 9 metres (351 inches), with a tolerance of +1.0 metre, -0.9 metre . Finally, connect the unit through its miniature male coaxial connector (Option 02) to ensure secure signal transmission.

Packaging List

The Bently Nevada 21508-02-12-90-02 arrives in its original factory packaging. This list describes only the physical components included in the box.

• 1 x 21508-02-12-90-02 Proximity Probe with integrated 9m cable

• Original factory packaging

Frequently Asked Questions (FAQ)

Q1: What is the primary application for the 21508-02-12-90-02?
A: The 21508-02-12-90-02 serves primarily for non-contact vibration and position monitoring on rotating machinery such as turbines, compressors, and pumps.

Q2: What does the "reverse mount" designation mean for this probe?
A: The reverse mount feature indicates that the 21508-02-12-90-02 uses a reverse thread (3/8-24). This design specifically addresses unique installation requirements in certain machinery housings.

Q3: What is the total cable length of this specific model?
A: This model provides a 9 metre (351 inches) cable, which the "-90" option identifies within the part number.

Q4: Can this sensor withstand contact with chemicals?
A: Yes, the 21508-02-12-90-02 resists direct contact with various chemicals, including lube oil, water, and 10% sulfuric acid.

Q5: What is the standard shipping method for this item?
A: We ship all orders via major global carriers such as FedEx, UPS, and DHL.