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This paper presents a study to investigate response of adjustable speed drives due to voltage sags. A small ASD of 0.39 kW, 50/60 Hz, and 400-480 V was used for testing how drives will respond to voltage sag types; A, B, C and D. The drive response is influenced by sag magnitude, sag duration and phase angle shift. Behavior of the diodes rectifier for conducting is influenced by sag magnitude and phase angle shift represented by sag of types C and D. The diodes rectifiers are reverse biased when it was supplied by voltage sags. Even though there are no charging currents to dc bus capacitor during voltage sags, the drives did not directly trip to certain sag magnitude and sag duration. Sensitivity of the ASD to voltage sag types is presented in voltage tolerance curve. Sag of type A produces highest sensitivity on the ASD and it trips for sag magnitude of 62.5% and 250 milliseconds in duration.

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This work proposes the dual axis solar tracker with mirror reflection for optimum output of solar panel by using arduino unoR3 as the control unit. The objectives of this work are to track and optimize the maximum output power of the solar panel by designing and developing a dual axis solar tracker with mirror reflection. The system includes a 10 watt solar panel, an arduino unoR3 and a customized mechanical body to carry the solar panel. This system will track and detect the angle of the sun to locate the surface of solar panel at the position and the angle where it can get maximum amount of energy. The sensors will detect the position of the sun and servo motors act as free moving neck to make it easier to move freely depending on the angle detected. The Light Depending Resistor (LDR) will be used in tracking system. These LDR will detect the existence of sunlight and therefore the mechanical hardware will move horizontal and vertical axis depending on the value of LDR detected to follow the angular degree of sun in order to get maximum and best result of absorbing energy. The final result obtained from dual axis solar tracker showed that the output power has been maximized compared to stationary panel. Based on the experimental result, it show that the designed system successful improve the performance of the solar panel.

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