This paper presents the FFT-ApEn analysis method for the fault detection of an electric motor under different rotating speeds. Motor vibration signals are analyzed using the Fast Fourier Transform (FFT) and Approximate Entropy (ApEn) to obtain the fault factor of a motor under different rotating speeds. The effectiveness of the proposed FFT and FFT-ApEn analyses for predicting the fault is verified through the experimental data. It is found that the FFT-ApEn analysis for the vibration signal can more precisely identify the fault as compared to the conventional FFT analysis method. In addition, the magnitudes of the frequency components are extracted for the recognition of the fault modes. The frequency spectrum analysis is used for distinguishing four operating statuses, i.e., normal, carbon brush failure, abnormal noise and bearing failure. Moreover, the FFT-ApEn method can successfully discriminate four different operating statuses of a motor without removing any motor parts. Hence, the FFT-ApEn analysis method is of great significance for a motor to have a real-time monitoring ability.
Piezoelectric pumps possess many advantages such as quiet operation, quick response, simple structure, and nonelectromagnetic radiation. This paper presents a PZT (Lead zirconate titanate) liquid pump with low power, high flow rate, small size, and light weight. The liquid pump is composed of the piezoelectric ceramic, elastomer valve, and PET (Polyethylene terephthalate) pump body. The power consumption, flow rate, body size and weight of the pump are 1 W, 800 ± 5% ml min-1 , 50 × 50 × 10 mm., and 50 g, respectively. Additionly, the pump works at an exciting voltage of 50 Hz, 40 V. According to the applied voltage or frequency to a PZT pump, the flow rate of the fluid is able to be controled. Besides, the liquid pump is suitable for various fluids such as water, alcohol, soda, hydrochloric acid, etc.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.