Digital Approach to Rotational Speed Measurement Using an Electrostatic Sensor

Area of Science:

• Engineering
• Sensor Technology
• Industrial Monitoring

Background:

• Rotational speed is critical for equipment condition monitoring and fault diagnosis in industrial settings.
• Harsh conditions like high temperatures and heavy dust pose challenges for traditional rotational speed measurement methods.
• Existing methods may lack the accuracy and robustness required for demanding industrial environments.

Purpose of the Study:

• To propose and validate a digital approach for measuring rotational speed using an electrostatic sensor.
• To address the limitations of existing methods in high-temperature, dusty industrial environments.
• To compare the performance of the proposed digital method against the auto-correlation method.

Main Methods:

• A strip of charged material is attached to the rotating shaft.
• An electrostatic sensor detects fluctuations from the charged strip, generating a signal.
• Signal conversion creates a square wave proportional to rotational speed.
• The M/T and T methods are used to calculate rotational speed from the square wave.

Main Results:

• The digital approach achieved relative errors within ±4‰, outperforming the auto-correlation method (up to 3.2%).
• The linearity of the digital approach, combined with M/T or T methods, was superior to the auto-correlation method.
• The digital method demonstrated better performance in terms of standard deviations and response speed.

Conclusions:

• The proposed digital method using electrostatic sensors is highly accurate and reliable for rotational speed measurement in challenging industrial conditions.
• This approach offers significant advantages over traditional auto-correlation methods in terms of precision, linearity, and dynamic performance.
• The electrostatic sensor-based digital method provides a robust solution for equipment condition monitoring and fault diagnosis in harsh environments.