The application scenarios of high-precision sensors

During the ultra-high-speed operation of magnetic or gas-suspended rotating shafts, testing the rotational speed of the gearless rotating shaft is a key technical issue. Here are several common testing methods and their application scenarios:

1. Electromagnetic Induction Sensor Method

Principle: The electromagnetic induction sensor detects the displacement changes on the rotating shaft surface and generates signals related to the rotational speed. These signals are processed (such as converted into square wave signals), and the rotational speed can be calculated by measuring the time interval between adjacent rising edges or the number of pulses within a fixed period.

Application: Suitable for magnetic suspension bearing systems, capable of achieving high-precision measurement, especially performing well in constant-speed conditions.-Magnetic levitation train sensors

2. Photoelectric Encoder Method

Principle: Install a photoelectric encoder on the rotating shaft to detect the changes in the grating on the encoder disc and generate pulse signals, thereby calculating the rotational speed.

Application: Suitable for scenarios requiring high precision and high response speed, such as high-speed air-floating main shafts in semiconductor processing equipment.

3. Laser Doppler Velocimetry Method

Principle: Utilize the laser Doppler effect to measure the frequency changes of reflected light to calculate the rotational speed of the shaft.

Application: Suitable for non-contact measurement, particularly suitable for rotational speed testing of ultra-high-speed shafts, such as high-performance equipment in aerospace fields.

4. Magnetic Encoder Method

Principle: Install magnetic marks on the rotating shaft and use magnetic sensors to detect the changes in the magnetic field to generate pulse signals, thereby calculating the rotational speed.

Application: Suitable for high-speed and high-precision scenarios, such as rotational speed monitoring in wind turbines or high-performance motors.

5. Vibration Spectrum Analysis Method

Principle: By analyzing the vibration spectrum during the rotation of the shaft, the frequency components related to the rotational speed are extracted, thereby indirectly calculating the rotational speed.

Application: Suitable for scenarios where sensors cannot be directly installed, such as certain enclosed high-speed rotating equipment.

In the speed testing of ultra-high-speed gearless shafts, the electro-vortex sensor method and the photoelectric encoder method are the most commonly used techniques, which are respectively applicable to magnetic levitation systems and semiconductor processing equipment. The laser Doppler velocimetry method and the magnetic encoder have advantages in high-precision and non-contact measurement. When choosing a specific method, it is necessary to comprehensively consider the working environment of the equipment, the accuracy requirements, and the installation conditions.