The Bently Nevada 21508-02-12-05-02 is a specialized reverse configuration proximity probe. This 8 mm probe belongs to the 7200 series family. It measures shaft vibration, axial position, and rotational speed. Many maintenance engineers choose this model for confined mounting locations.
Specifically, this probe features a reverse case configuration type. The total length option 05 gives only 0.5 metre (20 inches). Tolerance for total length is +0.13 metre / -0.05 metre (+5 inches / -2 inches). A miniature male coaxial connector (option 02) provides reliable signal transmission.
Unlike standard probes, this unit has no lead armor. This design reduces weight and increases flexibility. The tip diameter remains 8 mm with 3/8-24 reverse threads. Therefore, installation works well in bearing housings and gearboxes with limited space.
Power Requirements
The system needs a DC power supply between -17.5 Vdc and -26 Vdc. Maximum current consumption stays at 12 mA.
Output Characteristics
Calibrated range reaches 80 mils (2.0 mm). Measurement begins at approximately 10 mils (0.25 mm) from the probe face. Scale factor measures 200 mV/mil (7.87 V/mm) with ±4% accuracy when calibrated as a system. Including interchangeability errors, accuracy remains within ±9.5%.
Linearity stays within 0.8 mils (0.02 mm) of a 200 mV/mil straight line for system calibration. With interchangeability, linearity holds within 2.3 mils (0.06 mm). Frequency response covers 0 to 10 kHz (0 to 600,000 cpm). At 10 kHz, response drops by only -5%.
Temperature Sensitivity
Typically, scale factor changes by -3% at +150°F (+65°C) with a 50 mil gap (1.27 mm).
Operating temperature for the Proximitor ranges from -60°F to +212°F (-51°C to +100°C). For the probe and extension cable, the range is -30°F to +350°F (-34°C to +177°C). Relative humidity can reach 95%, non-condensing.
Corrosion Resistance
For this 8 mm probe, direct contact with the following substances does not affect operation:
Air and water
Lube oil
Ammonium hydroxide
Sulfuric acid (10%)
MEK (methyl-ethyl ketone)
DMF (Dimethylformamide)
The probe tip diameter is 8 mm. Case threads follow the 3/8-24 reverse standard. Total length option 05 gives 0.5 metre (20 inches). Tolerance for total length is +0.13 metre / -0.05 metre.
Lead armor is not present on this model. The connector option 02 is a miniature male coaxial type. System weight is 1.3 lbs (0.59 kg). Reverse configuration allows mounting in areas where standard probes cannot thread properly.
First, verify the mounting hole has reverse 3/8-24 threads. Next, gently thread the 21508-02-12-05-02 probe into place. Do not force the threads or overtighten the probe body.
Furthermore, maintain the recommended gap of approximately 10 mils (0.25 mm) from the probe face to the target. Since this probe has no lead armor, handle the cable with extra care. Avoid sharp bends near the connector.
Finally, verify power supply voltage before connecting the Proximitor. Use only Bently Nevada approved extension cables with the 21508-02-12-05-02 system for accurate readings.
1 x Bently Nevada 7200 series reverse probe (21508-02-12-05-02)
1 x Miniature male coaxial connector (pre-installed)
1 x Factory packing box with foam protection
All orders ship via FedEx, UPS, or DHL. Delivery typically takes 3 to 7 business days.
1. Why does the 21508-02-12-05-02 have no lead armor?
The armor is removed to reduce weight and increase cable flexibility. This design helps install the probe in tight spaces like gearbox housings.
2. What does reverse configuration mean for this probe?
Reverse configuration means the threads are oriented opposite to standard probes. This allows mounting in holes where a standard probe cannot thread properly.
3. Can I use this 0.5 metre probe with a longer extension cable?
Yes, but the total system length must match the calibrated length. Always consult Bently Nevada documentation before adding extension cables to 21508-02-12-05-02.
4. Is this probe resistant to oil and chemicals?
Yes. The 8 mm tip resists water, lube oil, 10% sulfuric acid, MEK, and DMF. It also handles ammonium hydroxide without performance loss.
5. How do I clean the reverse probe tip before installation?
Use a soft lint-free cloth with isopropyl alcohol. Do not use abrasive materials or strong solvents. Keep the connector dry and clean at all times.
| Brand Name | Bently Nevada |
| Model No. | 21508-02-12-05-02 |
| Product Type | Proximity Probe |
| hasMerchantReturnPolicy | Adjust according to reality |
| Shippingdetails | Adjust according to reality |
