Disclaimer: Always wear appropriate PPE when working around rotating machinery. Remove loose clothing and jewelry.
Hold the device 50mm to 500mm (2 to 20 inches) away from the rotating object. The laser spot should hit the reflective tape squarely. uni 3220
| Feature | Uni 3220 | Generic $20 Units | Fluke 931 | | :--- | :--- | :--- | :--- | | | 99,999 RPM | 30,000 RPM | 99,999 RPM | | Build Quality | Rubber armored | Hard plastic | Rubber armored | | Memory Recall | Yes (Last/Max/Min) | Usually only Max | Yes (Detailed stats) | | Price Point | $$ (Mid-range) | $ (Budget) | $$$$ (Premium) | Disclaimer: Always wear appropriate PPE when working around
Mastering the Uni 3220: The Ultimate Guide to Your Contactless Tachometer The laser spot should hit the reflective tape squarely
If you maintain industrial motors, RC cars, or even bicycle wheels, this $40-$60 tool will pay for itself the first time you diagnose a failing bearing (overheating due to high RPM) or calibrate a variable frequency drive.
Numbers keep jumping (e.g., 1500, then 3000). Fix: The sensor is seeing double reflections. Move the unit closer or cover any shiny surfaces behind the shaft with black electrical tape. Final Verdict The Uni 3220 is a workhorse. It isn't fancy, it doesn't have Bluetooth, and it won't log data to an app. But it will tell you exactly how fast something is spinning within +/- 0.05% accuracy every single time.
How to measure RPM safely, accurately, and without stopping your machines.
