Condition monitoring of cooling tower fan using K-band Doppler radar

A contactless condition monitoring technique for cooling tower fans is proposed using K-band Doppler radar. The system is realized using a commercial K-band Doppler radar module, the Hilbert transform is adopted to minimize the hardware complexity, and the Fourier transform is used to analyze the received signal. The proposed system has several advantages. First, Doppler radar is less vulnerable to the adverse effects of scattering from mist or dust, since the wavelength of a microwave is longer than that of a laser. Second, the proposed radar system can be applied to any sized fans, although it is suitable for cooling tower fans. Third, it can be easily implemented in a low-cost manner. The test results show that the RPM of the HANARO cooling tower fan agree with that of the motor in both low-speed and high-speed modes. The proposed system can be applied to the condition monitoring of cooling tower fans in thermal control systems.