
Product Overview
The Bently Nevada 21502-01 is an 8 mm Eddy Current Probe designed for non-contact measurement of shaft vibration, displacement, and position in industrial rotating machinery.
This probe is part of Bently Nevada’s eddy-current sensing technology line, providing accurate, reliable, and continuous monitoring of critical rotating equipment. Its 8 mm diameter allows for slightly larger shaft measurement ranges while maintaining high precision and stability.
Technical Specifications
| Parameter |
Details |
| Manufacturer |
Bently Nevada |
| Model |
21502-01 |
| Product Type |
Eddy Current Probe |
| Probe Diameter |
8 mm |
| Measurement Principle |
Eddy-current, non-contact sensing |
| Shipping Weight |
3 kg |
| Measurement Type |
Shaft vibration, displacement, and position |
| Linear Measurement Range |
2–3 mm (varies with system configuration) |
| Sensitivity |
200 mV/mil (typical) |
| Frequency Response |
Up to 10 kHz |
| Application |
Machinery protection, condition monitoring, and diagnostic measurement |
Function and Working Principle
The 21502-01 operates using eddy-current sensing:
- The probe tip generates a high-frequency electromagnetic field.
- When placed near a conductive target such as a rotating shaft, eddy currents are induced in the target surface.
- Variations in the gap between the probe and the target alter the electromagnetic field.
- These variations are converted into electrical signals proportional to shaft vibration and displacement.
Being non-contact, the probe ensures minimal wear and long-term reliable operation.
Key Features
- 8 mm probe diameter for larger gap applications
- Non-contact eddy-current sensing
- Accurate displacement and vibration measurement
- Wide frequency response for dynamic machinery analysis
- Rugged industrial construction
- Stable performance over long-term operation
- Suitable for continuous online monitoring
- Compatible with Bently Nevada monitoring systems
Industrial Applications
- Steam turbine shaft monitoring
- Gas turbine protection
- Compressor vibration and displacement analysis
- Pump shaft monitoring
- Generator condition monitoring
- Electric motor vibration analysis
- Gearbox diagnostics
- Oil and gas processing plants
- Power generation facilities
Installation Overview
- Mounted using probe housings or threaded fittings
- Positioned close to the shaft without contact
- Connected to extension cable and Proximitor signal conditioner
- Requires precise probe-to-shaft gap adjustment
- Suitable for radial and axial position measurements
Compatible Components
| Component |
Description |
| Bently Nevada Extension Cable |
Connects probe to signal conditioner |
| Proximitor Sensor |
Converts probe signals to electrical outputs |
| Machinery Protection System |
Provides alarm and shutdown functionality |
| Probe Housing Assembly |
Mechanical protection and mounting |
| Diagnostic Software |
Condition monitoring and analysis |
Alternative Models
| Model |
Description |
| 21500-00-08-10-02 |
5 mm Eddy Current Probe |
| 21500-00-12-05-02 |
5 mm Eddy Current Probe |
| 21502-02 |
8 mm Eddy Current Probe (variant) |
| 21502-03 |
8 mm Eddy Current Probe (variant with extended range) |
Key Advantages
- Accurate non-contact shaft measurement
- Reliable operation in critical machinery
- Larger 8 mm diameter for wider measurement gap
- Rugged and durable construction
- Supports predictive maintenance programs
- Long operational life
- Reduces unplanned downtime in machinery
Conclusion
The Bently Nevada 21502-01 8 mm Eddy Current Probe is a high-precision, durable, and compact device for continuous monitoring of shaft vibration, displacement, and position. Its eddy-current technology and rugged design make it ideal for industrial machinery protection and condition monitoring across turbines, compressors, pumps, and other rotating equipment.